当前目录：android/ijkplayer/ijkplayer-armv7a/src/main/jni/
ijkmedia/ijkplayer/android/ijkplayer_jni.c
头部：
#include <assert.h>
#include <string.h>
#include <pthread.h>
#include <jni.h>
#include <unistd.h>
#include "j4a/class/java/util/ArrayList.h"
#include "j4a/class/android/os/Bundle.h"
#include "j4a/class/tv/danmaku/ijk/media/player/IjkMediaPlayer.h"
#include "j4a/class/tv/danmaku/ijk/media/player/misc/IMediaDataSource.h"
#include "j4a/class/tv/danmaku/ijk/media/player/misc/IAndroidIO.h"
#include "ijksdl/ijksdl_log.h"
#include "../ff_ffplay.h"
#include "ffmpeg_api_jni.h"
#include "ijkplayer_android_def.h"
#include "ijkplayer_android.h"
#include "ijksdl/android/ijksdl_android_jni.h"
#include "ijksdl/android/ijksdl_codec_android_mediadef.h"
#include "ijkavformat/ijkavformat.h"
#define JNI_MODULE_PACKAGE "tv/danmaku/ijk/media/player"
#define JNI_CLASS_IJKPLAYER "tv/danmaku/ijk/media/player/IjkMediaPlayer"
#define JNI_IJK_MEDIA_EXCEPTION "tv/danmaku/ijk/media/player/exceptions/IjkMediaException"
#define IJK_CHECK_MPRET_GOTO(retval, env, label) \
JNI_CHECK_GOTO((retval != EIJK_INVALID_STATE), env, "java/lang/IllegalStateException", NULL, label); \
JNI_CHECK_GOTO((retval != EIJK_OUT_OF_MEMORY), env, "java/lang/OutOfMemoryError", NULL, label); \
JNI_CHECK_GOTO((retval == 0), env, JNI_IJK_MEDIA_EXCEPTION, NULL, label);
static JavaVM* g_jvm;
typedef struct player_fields_t {
pthread_mutex_t mutex;
jclass clazz;
} player_fields_t;
static player_fields_t g_clazz;
初始化：
static JNINativeMethod g_methods[] = {
{
"_setDataSource",
"(Ljava/lang/String;[Ljava/lang/String;[Ljava/lang/String;)V",
(void *) IjkMediaPlayer_setDataSourceAndHeaders
},
{ "_setDataSourceFd", "(I)V", (void *) IjkMediaPlayer_setDataSourceFd },
{ "_setDataSource", "(Ltv/danmaku/ijk/media/player/misc/IMediaDataSource;)V", (void *)IjkMediaPlayer_setDataSourceCallback },
{ "_setAndroidIOCallback", "(Ltv/danmaku/ijk/media/player/misc/IAndroidIO;)V", (void *)IjkMediaPlayer_setAndroidIOCallback },
{ "_setVideoSurface", "(Landroid/view/Surface;)V", (void *) IjkMediaPlayer_setVideoSurface },
{ "_prepareAsync", "()V", (void *) IjkMediaPlayer_prepareAsync },
{ "_start", "()V", (void *) IjkMediaPlayer_start },
{ "_stop", "()V", (void *) IjkMediaPlayer_stop },
{ "seekTo", "(J)V", (void *) IjkMediaPlayer_seekTo },
{ "_pause", "()V", (void *) IjkMediaPlayer_pause },
{ "isPlaying", "()Z", (void *) IjkMediaPlayer_isPlaying },
{ "getCurrentPosition", "()J", (void *) IjkMediaPlayer_getCurrentPosition },
{ "getDuration", "()J", (void *) IjkMediaPlayer_getDuration },
{ "_release", "()V", (void *) IjkMediaPlayer_release },
{ "_reset", "()V", (void *) IjkMediaPlayer_reset },
{ "setVolume", "(FF)V", (void *) IjkMediaPlayer_setVolume },
{ "getAudioSessionId", "()I", (void *) IjkMediaPlayer_getAudioSessionId },
{ "native_init", "()V", (void *) IjkMediaPlayer_native_init },
{ "native_setup", "(Ljava/lang/Object;)V", (void *) IjkMediaPlayer_native_setup },
{ "native_finalize", "()V", (void *) IjkMediaPlayer_native_finalize },
{ "_setOption", "(ILjava/lang/String;Ljava/lang/String;)V", (void *) IjkMediaPlayer_setOption },
{ "_setOption", "(ILjava/lang/String;J)V", (void *) IjkMediaPlayer_setOptionLong },
{ "_getColorFormatName", "(I)Ljava/lang/String;", (void *) IjkMediaPlayer_getColorFormatName },
{ "_getVideoCodecInfo", "()Ljava/lang/String;", (void *) IjkMediaPlayer_getVideoCodecInfo },
{ "_getAudioCodecInfo", "()Ljava/lang/String;", (void *) IjkMediaPlayer_getAudioCodecInfo },
{ "_getMediaMeta", "()Landroid/os/Bundle;", (void *) IjkMediaPlayer_getMediaMeta },
{ "_setLoopCount", "(I)V", (void *) IjkMediaPlayer_setLoopCount },
{ "_getLoopCount", "()I", (void *) IjkMediaPlayer_getLoopCount },
{ "_getPropertyFloat", "(IF)F", (void *) ijkMediaPlayer_getPropertyFloat },
{ "_setPropertyFloat", "(IF)V", (void *) ijkMediaPlayer_setPropertyFloat },
{ "_getPropertyLong", "(IJ)J", (void *) ijkMediaPlayer_getPropertyLong },
{ "_setPropertyLong", "(IJ)V", (void *) ijkMediaPlayer_setPropertyLong },
{ "_setStreamSelected", "(IZ)V", (void *) ijkMediaPlayer_setStreamSelected },
{ "native_profileBegin", "(Ljava/lang/String;)V", (void *) IjkMediaPlayer_native_profileBegin },
{ "native_profileEnd", "()V", (void *) IjkMediaPlayer_native_profileEnd },
{ "native_setLogLevel", "(I)V", (void *) IjkMediaPlayer_native_setLogLevel },
{ "_setFrameAtTime", "(Ljava/lang/String;JJII)V", (void *) IjkMediaPlayer_setFrameAtTime },
};
JNIEXPORT jint JNI_OnLoad(JavaVM *vm, void *reserved)
{
JNIEnv* env = NULL;
g_jvm = vm;
if ((*vm)->GetEnv(vm, (void**) &env, JNI_VERSION_1_4) != JNI_OK) {
return -1;
}
assert(env != NULL);
pthread_mutex_init(&g_clazz.mutex, NULL );
// FindClass returns LocalReference
IJK_FIND_JAVA_CLASS(env, g_clazz.clazz, JNI_CLASS_IJKPLAYER);
(*env)->RegisterNatives(env, g_clazz.clazz, g_methods, NELEM(g_methods) );
ijkmp_global_init();
ijkmp_global_set_inject_callback(inject_callback);
FFmpegApi_global_init(env);
return JNI_VERSION_1_4;
}
�
JNIEXPORT void JNI_OnUnload(JavaVM *jvm, void *reserved)
{
ijkmp_global_uninit();
pthread_mutex_destroy(&g_clazz.mutex);
}
首先分析 JNI_OnLoad
JNIEXPORT jint JNI_OnLoad(JavaVM *vm, void *reserved)
{
JNIEnv* env = NULL;
g_jvm = vm;
if ((*vm)->GetEnv(vm, (void**) &env, JNI_VERSION_1_4) != JNI_OK) {
return -1;
}
assert(env != NULL);
pthread_mutex_init(&g_clazz.mutex, NULL );
// FindClass returns LocalReference
IJK_FIND_JAVA_CLASS(env, g_clazz.clazz, JNI_CLASS_IJKPLAYER);
(*env)->RegisterNatives(env, g_clazz.clazz, g_methods, NELEM(g_methods) );
ijkmp_global_init();
ijkmp_global_set_inject_callback(inject_callback);
FFmpegApi_global_init(env);
return JNI_VERSION_1_4;
}
g_jvm = vm; 定义在：
ijkmedia/ijksdl/android/ijksdl_android_jni.c
static JavaVM *g_jvm;
static pthread_key_t g_thread_key;
static pthread_once_t g_key_once = PTHREAD_ONCE_INIT;
pthread_mutex_init(&g_clazz.mutex, NULL); 是定义在 ffmpeg 中的，ffmpeg 在 ijkplayer 根目录的 extra/ 里。该函数定义在 ffmpeg/compat/os2threads.h 或是 ffmpeg/compat/w32pthreads.h 中，用于适配不同的底层。然后封装在 ffmpeg/libavutil/thread.h 里统一调用。
IJK_FIND_JAVA_CLASS(env, g_clazz.clazz, JNI_CLASS_IJKPLAYER); 定义在：
ijkmedia/ijksdl/android/ijksdl_android_jni.h
#define IJK_FIND_JAVA_CLASS(env__, var__, classsign__) \
do { \
jclass clazz = (*env__)->FindClass(env__, classsign__); \
if (J4A_ExceptionCheck__catchAll(env) || !(clazz)) { \
ALOGE("FindClass failed: %s", classsign__); \
return -1; \
} \
var__ = (*env__)->NewGlobalRef(env__, clazz); \
if (J4A_ExceptionCheck__catchAll(env) || !(var__)) { \
ALOGE("FindClass::NewGlobalRef failed: %s", classsign__); \
(*env__)->DeleteLocalRef(env__, clazz); \
return -1; \
} \
(*env__)->DeleteLocalRef(env__, clazz); \
} while(0);
通过 classsign__ 和 env__ 得到 jvm 中 class 的实例引用，并以 GlobalRef 的方式赋予 var__。对于 GlobalRef 和 LocalRef 的详细讲解，可参考 Google 文档 和 java 文档
注册 g_methods 中的所有 Native 方法。方法详解
之后的 Java 和 Native 的方法表便可从 g_methods 中查找。
ijkmp_global_init(); 实现在：ijkmedia/ijkplayer/ijkplayer.c 中
void ijkmp_global_init()
{
ffp_global_init();
}
ffp_global_init(); 实现在：ijkmedia/ijkplayer/ff_ffplay.c 中
static AVPacket flush_pkt;
static bool g_ffmpeg_global_inited = false;
// lock manager 的回调
static int lockmgr(void **mtx, enum AVLockOp op)
{
switch (op) {
case AV_LOCK_CREATE:
*mtx = SDL_CreateMutex();
if (!*mtx) {
av_log(NULL, AV_LOG_FATAL, "SDL_CreateMutex(): %s\n", SDL_GetError());
return 1;
}
return 0;
case AV_LOCK_OBTAIN:
return !!SDL_LockMutex(*mtx);
case AV_LOCK_RELEASE:
return !!SDL_UnlockMutex(*mtx);
case AV_LOCK_DESTROY:
SDL_DestroyMutex(*mtx);
return 0;
}
return 1;
}
// av_log_set_call_back 的回调
static void ffp_log_callback_brief(void *ptr, int level, const char *fmt, va_list vl)
{
if (level > av_log_get_level())
return;
int ffplv __unused = log_level_av_to_ijk(level);
VLOG(ffplv, IJK_LOG_TAG, fmt, vl);
}
void ffp_global_init()
{
if (g_ffmpeg_global_inited)
return;
ALOGD("ijkmediaplayer version : %s", ijkmp_version());
/* register all codecs, demux and protocols */
avcodec_register_all();
#if CONFIG_AVDEVICE
avdevice_register_all();
#endif
#if CONFIG_AVFILTER
avfilter_register_all();
#endif
av_register_all();
ijkav_register_all();
avformat_network_init();
av_lockmgr_register(lockmgr);
av_log_set_callback(ffp_log_callback_brief);
av_init_packet(&flush_pkt);
flush_pkt.data = (uint8_t *)&flush_pkt;
g_ffmpeg_global_inited = true;
}
依然逐句分析
avcodec_register_all()，注册所有的 codec 方法，方法详解。
之后是两个配制：
#if CONFIG_AVDEVICE
...
#endif
#if CONFIG_AVFILTER
...
#endif
定义位于 ffmpeg/libffmpeg/config.h：
/* Automatically generated by configure - do not modify! */
#define CONFIG_AVDEVICE 0
#define CONFIG_AVFILTER 0
可见是通过配制文件生成的。
之后是avdevice_register_all()，注册所有的硬件方法，方法详解。
avfilter_register_all();，注册所有的 filter 方法，方法详解。
av_register_all();，初始化 libavformat 并注册所有的 muxers，demuxers，和 protocols，方法详解。
ijkav_register_all();，注册所有 ijkplayer 自定的一些协议，方法详解。
avformat_network_init();，初始化网络的内容，方法详解。
av_lockmgr_register(lockmgr);，注册一个用户提供的锁 lock manager，方法详解。
av_log_set_callback(ffp_log_callback_brief);，设置 logging 的回调，方法详解。
av_init_packet(&flush_pkt);，初始化一个 packet，方法详解。
flush_pkt.data = (uint8_t *)&flush_pkt;，截 flush_pkt 的前 8 位作 data。
g_ffmpeg_global_inited = true;，标记初始化完成。
将之赋予类型为 FFPlayer 的 app_ctx->func_on_app_event 上，在对应 app_event 发生变化时便可及时获取回调。
回调的实现在 ijkplayer_ini.c 中：
// NOTE: support to be called from read_thread
static int
inject_callback(void *opaque, int what, void *data, size_t data_size)
{
JNIEnv *env = NULL;
jobject jbundle = NULL;
int ret = -1;
SDL_JNI_SetupThreadEnv(&env);
jobject weak_thiz = (jobject) opaque;
if (weak_thiz == NULL )
goto fail;
switch (what) {
case AVAPP_CTRL_WILL_HTTP_OPEN:
case AVAPP_CTRL_WILL_LIVE_OPEN:
case AVAPP_CTRL_WILL_CONCAT_SEGMENT_OPEN: {
AVAppIOControl *real_data = (AVAppIOControl *)data;
real_data->is_handled = 0;
jbundle = J4AC_Bundle__Bundle__catchAll(env);
if (!jbundle) {
ALOGE("%s: J4AC_Bundle__Bundle__catchAll failed for case %d\n", __func__, what);
goto fail;
}
J4AC_Bundle__putString__withCString__catchAll(env, jbundle, "url", real_data->url);
J4AC_Bundle__putInt__withCString__catchAll(env, jbundle, "segment_index", real_data->segment_index);
J4AC_Bundle__putInt__withCString__catchAll(env, jbundle, "retry_counter", real_data->retry_counter);
real_data->is_handled = J4AC_IjkMediaPlayer__onNativeInvoke(env, weak_thiz, what, jbundle);
if (J4A_ExceptionCheck__catchAll(env)) {
goto fail;
}
J4AC_Bundle__getString__withCString__asCBuffer(env, jbundle, "url", real_data->url, sizeof(real_data->url));
if (J4A_ExceptionCheck__catchAll(env)) {
goto fail;
}
ret = 0;
break;
}
case AVAPP_EVENT_WILL_HTTP_OPEN:
case AVAPP_EVENT_DID_HTTP_OPEN:
case AVAPP_EVENT_WILL_HTTP_SEEK:
case AVAPP_EVENT_DID_HTTP_SEEK: {
AVAppHttpEvent *real_data = (AVAppHttpEvent *) data;
jbundle = J4AC_Bundle__Bundle__catchAll(env);
if (!jbundle) {
ALOGE("%s: J4AC_Bundle__Bundle__catchAll failed for case %d\n", __func__, what);
goto fail;
}
J4AC_Bundle__putString__withCString__catchAll(env, jbundle, "url", real_data->url);
J4AC_Bundle__putLong__withCString__catchAll(env, jbundle, "offset", real_data->offset);
J4AC_Bundle__putInt__withCString__catchAll(env, jbundle, "error", real_data->error);
J4AC_Bundle__putInt__withCString__catchAll(env, jbundle, "http_code", real_data->http_code);
J4AC_Bundle__putLong__withCString__catchAll(env, jbundle, "file_size", real_data->filesize);
J4AC_IjkMediaPlayer__onNativeInvoke(env, weak_thiz, what, jbundle);
if (J4A_ExceptionCheck__catchAll(env))
goto fail;
ret = 0;
break;
}
case AVAPP_CTRL_DID_TCP_OPEN:
case AVAPP_CTRL_WILL_TCP_OPEN: {
AVAppTcpIOControl *real_data = (AVAppTcpIOControl *)data;
jbundle = J4AC_Bundle__Bundle__catchAll(env);
if (!jbundle) {
ALOGE("%s: J4AC_Bundle__Bundle__catchAll failed for case %d\n", __func__, what);
goto fail;
}
J4AC_Bundle__putInt__withCString__catchAll(env, jbundle, "error", real_data->error);
J4AC_Bundle__putInt__withCString__catchAll(env, jbundle, "family", real_data->family);
J4AC_Bundle__putString__withCString__catchAll(env, jbundle, "ip", real_data->ip);
J4AC_Bundle__putInt__withCString__catchAll(env, jbundle, "port", real_data->port);
J4AC_Bundle__putInt__withCString__catchAll(env, jbundle, "fd", real_data->fd);
J4AC_IjkMediaPlayer__onNativeInvoke(env, weak_thiz, what, jbundle);
if (J4A_ExceptionCheck__catchAll(env))
goto fail;
ret = 0;
break;
}
default: {
ret = 0;
}
}
fail:
SDL_JNI_DeleteLocalRefP(env, &jbundle);
return ret;
}
该方法声明在 ijkmedia/ijkplayer/android/ffmpeg_api_jni.h 中：
int FFmpegApi_global_init(JNIEnv *env);
实现在 ijkmedia/ijkplayer/android/ffmpeg_api_jni.c 中：
#define JNI_CLASS_FFMPEG_API "tv/danmaku/ijk/media/player/ffmpeg/FFmpegApi"
int FFmpegApi_global_init(JNIEnv *env)
{
int ret = 0;
IJK_FIND_JAVA_CLASS(env, g_clazz.clazz, JNI_CLASS_FFMPEG_API);
(*env)->RegisterNatives(env, g_clazz.clazz, g_methods, NELEM(g_methods));
return ret;
}
将 FFmpegApi 的 JAVA 类加载到 JVM 当中。
返回 JNI_VERSION_1_4。
声明在 ijkmedia/ijkplayer/ijkplayer.h 中：
typedef struct IjkMediaPlayer IjkMediaPlayer;
实现在 ijkmedia/ijkplayer/ijkplayer_internal.h 中：
#ifndef IJKPLAYER_ANDROID__IJKPLAYER_INTERNAL_H
#define IJKPLAYER_ANDROID__IJKPLAYER_INTERNAL_H
#include <assert.h>
#include "ijksdl/ijksdl.h"
#include "ff_fferror.h"
#include "ff_ffplay.h"
#include "ijkplayer.h"
struct IjkMediaPlayer {
volatile int ref_count;
pthread_mutex_t mutex;
FFPlayer *ffplayer;
int (*msg_loop)(void*);
SDL_Thread *msg_thread;
SDL_Thread _msg_thread;
int mp_state;
char *data_source;
void *weak_thiz;
int restart;
int restart_from_beginning;
int seek_req;
long seek_msec;
};
#endif
于 ijkmedia/ijkplayer/android/ijkplayer_jni.c 中：
static int message_loop(void *arg);
static int message_loop(void *arg)
{
MPTRACE("%s\n", __func__);
JNIEnv *env = NULL;
if (JNI_OK != SDL_JNI_SetupThreadEnv(&env)) {
ALOGE("%s: SetupThreadEnv failed\n", __func__);
return -1;
}
IjkMediaPlayer *mp = (IjkMediaPlayer*) arg;
JNI_CHECK_GOTO(mp, env, NULL, "mpjni: native_message_loop: null mp", LABEL_RETURN);
message_loop_n(env, mp);
LABEL_RETURN:
ijkmp_dec_ref_p(&mp);
MPTRACE("message_loop exit");
return 0;
}
前面是一些初始化和空判断，后面是引用的释放。中间 message_loop_n(env, mp); 是重点函数。
static void message_loop_n(JNIEnv *env, IjkMediaPlayer *mp)
{
jobject weak_thiz = (jobject) ijkmp_get_weak_thiz(mp);
JNI_CHECK_GOTO(weak_thiz, env, NULL, "mpjni: message_loop_n: null weak_thiz", LABEL_RETURN);
while (1) {
AVMessage msg;
int retval = ijkmp_get_msg(mp, &msg, 1);
if (retval < 0)
break;
// block-get should never return 0
assert(retval > 0);
switch (msg.what) {
case FFP_MSG_FLUSH:
MPTRACE("FFP_MSG_FLUSH:\n");
post_event(env, weak_thiz, MEDIA_NOP, 0, 0);
break;
case FFP_MSG_ERROR:
MPTRACE("FFP_MSG_ERROR: %d\n", msg.arg1);
post_event(env, weak_thiz, MEDIA_ERROR, MEDIA_ERROR_IJK_PLAYER, msg.arg1);
break;
case FFP_MSG_PREPARED:
MPTRACE("FFP_MSG_PREPARED:\n");
post_event(env, weak_thiz, MEDIA_PREPARED, 0, 0);
break;
case FFP_MSG_COMPLETED:
MPTRACE("FFP_MSG_COMPLETED:\n");
post_event(env, weak_thiz, MEDIA_PLAYBACK_COMPLETE, 0, 0);
break;
case FFP_MSG_VIDEO_SIZE_CHANGED:
MPTRACE("FFP_MSG_VIDEO_SIZE_CHANGED: %d, %d\n", msg.arg1, msg.arg2);
post_event(env, weak_thiz, MEDIA_SET_VIDEO_SIZE, msg.arg1, msg.arg2);
break;
case FFP_MSG_SAR_CHANGED:
MPTRACE("FFP_MSG_SAR_CHANGED: %d, %d\n", msg.arg1, msg.arg2);
post_event(env, weak_thiz, MEDIA_SET_VIDEO_SAR, msg.arg1, msg.arg2);
break;
case FFP_MSG_VIDEO_RENDERING_START:
MPTRACE("FFP_MSG_VIDEO_RENDERING_START:\n");
post_event(env, weak_thiz, MEDIA_INFO, MEDIA_INFO_VIDEO_RENDERING_START, 0);
break;
case FFP_MSG_AUDIO_RENDERING_START:
MPTRACE("FFP_MSG_AUDIO_RENDERING_START:\n");
post_event(env, weak_thiz, MEDIA_INFO, MEDIA_INFO_AUDIO_RENDERING_START, 0);
break;
case FFP_MSG_VIDEO_ROTATION_CHANGED:
MPTRACE("FFP_MSG_VIDEO_ROTATION_CHANGED: %d\n", msg.arg1);
post_event(env, weak_thiz, MEDIA_INFO, MEDIA_INFO_VIDEO_ROTATION_CHANGED, msg.arg1);
break;
case FFP_MSG_AUDIO_DECODED_START:
MPTRACE("FFP_MSG_AUDIO_DECODED_START:\n");
post_event(env, weak_thiz, MEDIA_INFO, MEDIA_INFO_AUDIO_DECODED_START, 0);
break;
case FFP_MSG_VIDEO_DECODED_START:
MPTRACE("FFP_MSG_VIDEO_DECODED_START:\n");
post_event(env, weak_thiz, MEDIA_INFO, MEDIA_INFO_VIDEO_DECODED_START, 0);
break;
case FFP_MSG_OPEN_INPUT:
MPTRACE("FFP_MSG_OPEN_INPUT:\n");
post_event(env, weak_thiz, MEDIA_INFO, MEDIA_INFO_OPEN_INPUT, 0);
break;
case FFP_MSG_FIND_STREAM_INFO:
MPTRACE("FFP_MSG_FIND_STREAM_INFO:\n");
post_event(env, weak_thiz, MEDIA_INFO, MEDIA_INFO_FIND_STREAM_INFO, 0);
break;
case FFP_MSG_COMPONENT_OPEN:
MPTRACE("FFP_MSG_COMPONENT_OPEN:\n");
post_event(env, weak_thiz, MEDIA_INFO, MEDIA_INFO_COMPONENT_OPEN, 0);
break;
case FFP_MSG_BUFFERING_START:
MPTRACE("FFP_MSG_BUFFERING_START:\n");
post_event(env, weak_thiz, MEDIA_INFO, MEDIA_INFO_BUFFERING_START, msg.arg1);
break;
case FFP_MSG_BUFFERING_END:
MPTRACE("FFP_MSG_BUFFERING_END:\n");
post_event(env, weak_thiz, MEDIA_INFO, MEDIA_INFO_BUFFERING_END, msg.arg1);
break;
case FFP_MSG_BUFFERING_UPDATE:
// MPTRACE("FFP_MSG_BUFFERING_UPDATE: %d, %d", msg.arg1, msg.arg2);
post_event(env, weak_thiz, MEDIA_BUFFERING_UPDATE, msg.arg1, msg.arg2);
break;
case FFP_MSG_BUFFERING_BYTES_UPDATE:
break;
case FFP_MSG_BUFFERING_TIME_UPDATE:
break;
case FFP_MSG_SEEK_COMPLETE:
MPTRACE("FFP_MSG_SEEK_COMPLETE:\n");
post_event(env, weak_thiz, MEDIA_SEEK_COMPLETE, 0, 0);
break;
case FFP_MSG_ACCURATE_SEEK_COMPLETE:
MPTRACE("FFP_MSG_ACCURATE_SEEK_COMPLETE:\n");
post_event(env, weak_thiz, MEDIA_INFO, MEDIA_INFO_MEDIA_ACCURATE_SEEK_COMPLETE, msg.arg1);
break;
case FFP_MSG_PLAYBACK_STATE_CHANGED:
break;
case FFP_MSG_TIMED_TEXT:
if (msg.obj) {
jstring text = (*env)->NewStringUTF(env, (char *)msg.obj);
post_event2(env, weak_thiz, MEDIA_TIMED_TEXT, 0, 0, text);
J4A_DeleteLocalRef__p(env, &text);
}
else {
post_event2(env, weak_thiz, MEDIA_TIMED_TEXT, 0, 0, NULL);
}
break;
case FFP_MSG_GET_IMG_STATE:
if (msg.obj) {
jstring file_name = (*env)->NewStringUTF(env, (char *)msg.obj);
post_event2(env, weak_thiz, MEDIA_GET_IMG_STATE, msg.arg1, msg.arg2, file_name);
J4A_DeleteLocalRef__p(env, &file_name);
}
else {
post_event2(env, weak_thiz, MEDIA_GET_IMG_STATE, msg.arg1, msg.arg2, NULL);
}
break;
case FFP_MSG_VIDEO_SEEK_RENDERING_START:
MPTRACE("FFP_MSG_VIDEO_SEEK_RENDERING_START:\n");
post_event(env, weak_thiz, MEDIA_INFO, MEDIA_INFO_VIDEO_SEEK_RENDERING_START, msg.arg1);
break;
case FFP_MSG_AUDIO_SEEK_RENDERING_START:
MPTRACE("FFP_MSG_AUDIO_SEEK_RENDERING_START:\n");
post_event(env, weak_thiz, MEDIA_INFO, MEDIA_INFO_AUDIO_SEEK_RENDERING_START, msg.arg1);
break;
default:
ALOGE("unknown FFP_MSG_xxx(%d)\n", msg.what);
break;
}
msg_free_res(&msg);
}
LABEL_RETURN:
;
}
int retval = ijkmp_get_msg(mp, &msg, 1); 得到当前发送的 msg。方法详解
FFP_MSG_FLUSH 等一系列 EVENT 的声明详解
对于每个 msg，都有或是 post_event 方法，或是 post_event2，用来传 event。
inline static void post_event(JNIEnv *env, jobject weak_this, int what, int arg1, int arg2)
{
// MPTRACE("post_event(%p, %p, %d, %d, %d)", (void*)env, (void*) weak_this, what, arg1, arg2);
J4AC_IjkMediaPlayer__postEventFromNative(env, weak_this, what, arg1, arg2, NULL);
// MPTRACE("post_event()=void");
}
inline static void post_event2(JNIEnv *env, jobject weak_this, int what, int arg1, int arg2, jobject obj)
{
// MPTRACE("post_event2(%p, %p, %d, %d, %d, %p)", (void*)env, (void*) weak_this, what, arg1, arg2, (void*)obj);
J4AC_IjkMediaPlayer__postEventFromNative(env, weak_this, what, arg1, arg2, obj);
// MPTRACE("post_event2()=void");
}
可看到，都会走一个统一的回调方法 J4AC_IjkMediaPlayer__postEventFromNative，方法声明在 ijkmedia/ijkj4a/j4a/class/tv/danmaku/ijk/media/player/IjkMediaPlayer.h 中：
#define J4AC_IjkMediaPlayer__postEventFromNative J4AC_tv_danmaku_ijk_media_player_IjkMediaPlayer__postEventFromNative
实现在对应的 ijkmedia/ijkj4a/j4a/class/tv/danmaku/ijk/media/player/IjkMediaPlayer.c 中：
typedef struct J4AC_tv_danmaku_ijk_media_player_IjkMediaPlayer {
jclass id;
jfieldID field_mNativeMediaPlayer;
jfieldID field_mNativeMediaDataSource;
jfieldID field_mNativeAndroidIO;
jmethodID method_postEventFromNative;
jmethodID method_onSelectCodec;
jmethodID method_onNativeInvoke;
} J4AC_tv_danmaku_ijk_media_player_IjkMediaPlayer;
static J4AC_tv_danmaku_ijk_media_player_IjkMediaPlayer class_J4AC_tv_danmaku_ijk_media_player_IjkMediaPlayer;
void J4AC_tv_danmaku_ijk_media_player_IjkMediaPlayer__postEventFromNative(JNIEnv *env, jobject weakThiz, jint what, jint arg1, jint arg2, jobject obj)
{
(*env)->CallStaticVoidMethod(env, class_J4AC_tv_danmaku_ijk_media_player_IjkMediaPlayer.id, class_J4AC_tv_danmaku_ijk_media_player_IjkMediaPlayer.method_postEventFromNative, weakThiz, what, arg1, arg2, obj);
}
其中，method_postEventFromNative 的初始化：
int J4A_loadClass__J4AC_tv_danmaku_ijk_media_player_IjkMediaPlayer(JNIEnv *env)
{
...
sign = "tv/danmaku/ijk/media/player/IjkMediaPlayer";
class_J4AC_tv_danmaku_ijk_media_player_IjkMediaPlayer.id = J4A_FindClass__asGlobalRef__catchAll(env, sign);
if (class_J4AC_tv_danmaku_ijk_media_player_IjkMediaPlayer.id == NULL)
goto fail;
...
class_id = class_J4AC_tv_danmaku_ijk_media_player_IjkMediaPlayer.id;
name = "postEventFromNative";
sign = "(Ljava/lang/Object;IIILjava/lang/Object;)V";
class_J4AC_tv_danmaku_ijk_media_player_IjkMediaPlayer.method_postEventFromNative = J4A_GetStaticMethodID__catchAll(env, class_id, name, sign);
if (class_J4AC_tv_danmaku_ijk_media_player_IjkMediaPlayer.method_postEventFromNative == NULL)
goto fail;
...
}
可知，是对应着 tv/danmaku/ijk/media/player/IjkMediaPlayer.Java 中的 postEventFromNative 方法。下面来分析一下 android/ijkplayer/ijkplayer-java/src/main/java/tv/danmaku/ijk/media/player/IjkMediaPlayer.java：
/*
* Called from native code when an interesting event happens. This method
* just uses the EventHandler system to post the event back to the main app
* thread. We use a weak reference to the original IjkMediaPlayer object so
* that the native code is safe from the object disappearing from underneath
* it. (This is the cookie passed to native_setup().)
*/
@CalledByNative
private static void postEventFromNative(Object weakThiz, int what,
int arg1, int arg2, Object obj) {
if (weakThiz == null)
return;
@SuppressWarnings("rawtypes")
IjkMediaPlayer mp = (IjkMediaPlayer) ((WeakReference) weakThiz).get();
if (mp == null) {
return;
}
if (what == MEDIA_INFO && arg1 == MEDIA_INFO_STARTED_AS_NEXT) {
// this acquires the wakelock if needed, and sets the client side
// state
mp.start();
}
if (mp.mEventHandler != null) {
Message m = mp.mEventHandler.obtainMessage(what, arg1, arg2, obj);
mp.mEventHandler.sendMessage(m);
}
}
这样就和 Java 的代码联系在一起了。然后再看 mEventHandler 声明：
private EventHandler mEventHandler;
初始化：
private void initPlayer(IjkLibLoader libLoader) {
loadLibrariesOnce(libLoader);
initNativeOnce();
Looper looper;
if ((looper = Looper.myLooper()) != null) {
mEventHandler = new EventHandler(this, looper);
} else if ((looper = Looper.getMainLooper()) != null) {
mEventHandler = new EventHandler(this, looper);
} else {
mEventHandler = null;
}
/*
* Native setup requires a weak reference to our object. It's easier to
* create it here than in C++.
*/
native_setup(new WeakReference<IjkMediaPlayer>(this));
}
EventHandler 是 IjkMediaPlayer 中的静态内部类，主要看 handleMessage 方法：
@Override
public void handleMessage(Message msg) {
IjkMediaPlayer player = mWeakPlayer.get();
if (player == null || player.mNativeMediaPlayer == 0) {
DebugLog.w(TAG,
"IjkMediaPlayer went away with unhandled events");
return;
}
switch (msg.what) {
case MEDIA_PREPARED:
player.notifyOnPrepared();
return;
case MEDIA_PLAYBACK_COMPLETE:
player.stayAwake(false);
player.notifyOnCompletion();
return;
case MEDIA_BUFFERING_UPDATE:
long bufferPosition = msg.arg1;
if (bufferPosition < 0) {
bufferPosition = 0;
}
long percent = 0;
long duration = player.getDuration();
if (duration > 0) {
percent = bufferPosition * 100 / duration;
}
if (percent >= 100) {
percent = 100;
}
// DebugLog.efmt(TAG, "Buffer (%d%%) %d/%d", percent, bufferPosition, duration);
player.notifyOnBufferingUpdate((int)percent);
return;
case MEDIA_SEEK_COMPLETE:
player.notifyOnSeekComplete();
return;
case MEDIA_SET_VIDEO_SIZE:
player.mVideoWidth = msg.arg1;
player.mVideoHeight = msg.arg2;
player.notifyOnVideoSizeChanged(player.mVideoWidth, player.mVideoHeight,
player.mVideoSarNum, player.mVideoSarDen);
return;
case MEDIA_ERROR:
DebugLog.e(TAG, "Error (" + msg.arg1 + "," + msg.arg2 + ")");
if (!player.notifyOnError(msg.arg1, msg.arg2)) {
player.notifyOnCompletion();
}
player.stayAwake(false);
return;
case MEDIA_INFO:
switch (msg.arg1) {
case MEDIA_INFO_VIDEO_RENDERING_START:
DebugLog.i(TAG, "Info: MEDIA_INFO_VIDEO_RENDERING_START\n");
break;
}
player.notifyOnInfo(msg.arg1, msg.arg2);
// No real default action so far.
return;
case MEDIA_TIMED_TEXT:
if (msg.obj == null) {
player.notifyOnTimedText(null);
} else {
IjkTimedText text = new IjkTimedText(new Rect(0, 0, 1, 1), (String)msg.obj);
player.notifyOnTimedText(text);
}
return;
case MEDIA_NOP: // interface test message - ignore
break;
case MEDIA_SET_VIDEO_SAR:
player.mVideoSarNum = msg.arg1;
player.mVideoSarDen = msg.arg2;
player.notifyOnVideoSizeChanged(player.mVideoWidth, player.mVideoHeight,
player.mVideoSarNum, player.mVideoSarDen);
break;
default:
DebugLog.e(TAG, "Unknown message type " + msg.what);
}
}
每种回调可以慢慢分析，此不赘述。但是可以看出，这里的信息定义与之前的相比并不完整，MEDIA_PREPARED 等的声明详解，此处可以扩展以获得更多的信息。
通过 g_method，可以找到 "native_init", "()V", (void *) IjkMediaPlayer_native_init，这是在 example 中 IjkMediaPlayer.java 的构造方法中调用的。
native 方法实现在 ijkmedia/ijkplayer/android/ijkplayer_jni.c 中：
static void
IjkMediaPlayer_native_init(JNIEnv *env)
{
MPTRACE("%s\n", __func__);
}
仅仅是一个日志。
通过 g_method，可以找到 "native_setup", "(Ljava/lang/Object;)V", (void *) IjkMediaPlayer_native_setup，这是在 example 中 IjkMediaPlayer.java 的构造方法中调用的。
native 方法实现在 ijkmedia/ijkplayer/android/ijkplayer_jni.c 中：
static void IjkMediaPlayer_native_setup(JNIEnv *env, jobject thiz, jobject weak_this);
static void
IjkMediaPlayer_native_setup(JNIEnv *env, jobject thiz, jobject weak_this)
{
MPTRACE("%s\n", __func__);
IjkMediaPlayer *mp = ijkmp_android_create(message_loop);
JNI_CHECK_GOTO(mp, env, "java/lang/OutOfMemoryError", "mpjni: native_setup: ijkmp_create() failed", LABEL_RETURN);
jni_set_media_player(env, thiz, mp);
ijkmp_set_weak_thiz(mp, (*env)->NewGlobalRef(env, weak_this));
ijkmp_set_inject_opaque(mp, ijkmp_get_weak_thiz(mp));
ijkmp_set_ijkio_inject_opaque(mp, ijkmp_get_weak_thiz(mp));
ijkmp_android_set_mediacodec_select_callback(mp, mediacodec_select_callback, ijkmp_get_weak_thiz(mp));
LABEL_RETURN:
ijkmp_dec_ref_p(&mp);
}
逐步分析：
IjkMediaPlayer *mp = ijkmp_android_create(message_loop); 创建一个 IjkMediaPlayer 的 Android 下的实例。方法详解
JNI_CHECK_GOTO(mp, env, "java/lang/OutOfMemoryError", "mpjni: native_setup: ijkmp_create() failed", LABEL_RETURN);
判空。
jni_set_media_player(env, thiz, mp); 存储 mp 的引用。方法详解
ijkmp_set_weak_thiz(mp, (*env)->NewGlobalRef(env, weak_this)); 让 IjkMediaPlayer 得到 this 的引用。方法详解
ijkmp_set_inject_opaque(mp, ijkmp_get_weak_thiz(mp)); 注入 opaque。方法详解
ijkmp_set_ijkio_inject_opaque(mp, ijkmp_get_weak_thiz(mp)); 注入 ijkio 的 opaque。方法详解
ijkmp_android_set_mediacodec_select_callback(mp,
mediacodec_select_callback, ijkmp_get_weak_thiz(mp));
设置 media codec 选择之后的回调。方法详解
ijkmp_dec_ref_p(&mp); 最后释放 mp 的引用。
mediacodec_select_callback 的实现是：
static bool mediacodec_select_callback(void *opaque, ijkmp_mediacodecinfo_context *mcc)
{
JNIEnv *env = NULL;
jobject weak_this = (jobject) opaque;
const char *found_codec_name = NULL;
if (JNI_OK != SDL_JNI_SetupThreadEnv(&env)) {
ALOGE("%s: SetupThreadEnv failed\n", __func__);
return -1;
}
found_codec_name = J4AC_IjkMediaPlayer__onSelectCodec__withCString__asCBuffer(env, weak_this, mcc->mime_type, mcc->profile, mcc->level, mcc->codec_name, sizeof(mcc->codec_name));
if (J4A_ExceptionCheck__catchAll(env) || !found_codec_name) {
ALOGE("%s: onSelectCodec failed\n", __func__);
goto fail;
}
fail:
return found_codec_name;
}
会在回调中返回 codec 的名称。
通过 ijkmedia/ijkplayer/android/ijkplayer_jni.c 的 g_method 表，可以看到 setDataSource 对应几个 native 方法。
static JNINativeMethod g_methods[] = {
{
"_setDataSource",
"(Ljava/lang/String;[Ljava/lang/String;[Ljava/lang/String;)V",
(void *) IjkMediaPlayer_setDataSourceAndHeaders
},
{ "_setDataSourceFd", "(I)V", (void *) IjkMediaPlayer_setDataSourceFd },
{ "_setDataSource", "(Ltv/danmaku/ijk/media/player/misc/IMediaDataSource;)V", (void *)IjkMediaPlayer_setDataSourceCallback },
...
}
先看第三个方法，IjkMediaPlayer_setDataSourceCallback，因为在 Example 中，封装的 setDataSource，包含 url 和 path，最后指向的都是这个方法。
前面的两个方法的基本流程都是一样的：
static void IjkMediaPlayer...setDataSource...(JNIEnv *env, jobject thiz, jstring path, ...)
{
...
IjkMediaPlayer *mp = jni_get_media_player(env, thiz);
...
retval = ijkmp_set_data_source(mp, c_path);
...
ijkmp_dec_ref_p(&mp);
}
下面再详细分析第三个方法。
IjkMediaPlayer_setDataSourceCallback 实现在 ijkmedia/ijkplayer/android/ijkplayer_jni.c :
static void
IjkMediaPlayer_setDataSourceCallback(JNIEnv *env, jobject thiz, jobject callback)
{
MPTRACE("%s\n", __func__);
int retval = 0;
char uri[128];
int64_t nativeMediaDataSource = 0;
IjkMediaPlayer *mp = jni_get_media_player(env, thiz);
JNI_CHECK_GOTO(callback, env, "java/lang/IllegalArgumentException", "mpjni: setDataSourceCallback: null fd", LABEL_RETURN);
JNI_CHECK_GOTO(mp, env, "java/lang/IllegalStateException", "mpjni: setDataSourceCallback: null mp", LABEL_RETURN);
nativeMediaDataSource = jni_set_media_data_source(env, thiz, callback);
JNI_CHECK_GOTO(nativeMediaDataSource, env, "java/lang/IllegalStateException", "mpjni: jni_set_media_data_source: NewGlobalRef", LABEL_RETURN);
ALOGV("setDataSourceCallback: %"PRId64"\n", nativeMediaDataSource);
snprintf(uri, sizeof(uri), "ijkmediadatasource:%"PRId64, nativeMediaDataSource);
retval = ijkmp_set_data_source(mp, uri);
IJK_CHECK_MPRET_GOTO(retval, env, LABEL_RETURN);
LABEL_RETURN:
ijkmp_dec_ref_p(&mp);
}
依然逐步分析：
IjkMediaPlayer *mp = jni_get_media_player(env, thiz);，获得 IjkMediaPlayer 的引用，方法详解。
JNI_CHECK_GOTO(condition__, env__, exception__, msg__, label__)，判空检查，若为空，则抛出异常，跳转到 label__ 处，方法详解。
nativeMediaDataSource = jni_set_media_data_source(env, thiz, callback);，设置视频的 MediaDataSource。方法详解。
retval = ijkmp_set_data_source(mp, uri);，方法详解。
IJK_CHECK_MPRET_GOTO(retval, env, LABEL_RETURN); 检查返回值，判断 set_data_source 是否成功。
ijkmp_dec_ref_p(&mp); 对应释放对 mp 的引用。方法详解。
通过 ijkmedia/ijkplayer/android/ijkplayer_jni.c 的 g_method 表，可以看到 prepareAsync 对应几个 native 方法：
static JNINativeMethod g_methods[] = {
...
{ "_prepareAsync", "()V", (void *) IjkMediaPlayer_prepareAsync },
...
}
实现：
static void
IjkMediaPlayer_prepareAsync(JNIEnv *env, jobject thiz)
{
MPTRACE("%s\n", __func__);
int retval = 0;
IjkMediaPlayer *mp = jni_get_media_player(env, thiz);
JNI_CHECK_GOTO(mp, env, "java/lang/IllegalStateException", "mpjni: prepareAsync: null mp", LABEL_RETURN);
retval = ijkmp_prepare_async(mp);
IJK_CHECK_MPRET_GOTO(retval, env, LABEL_RETURN);
LABEL_RETURN:
ijkmp_dec_ref_p(&mp);
}
方法 int jni_prepare_async(IjkMediaPlayer *mp) 声明和实现都在 ijkmedia/ijkplayer/ijkplayer.c 中：
int ijkmp_prepare_async(IjkMediaPlayer *mp)
{
assert(mp);
MPTRACE("ijkmp_prepare_async()\n");
pthread_mutex_lock(&mp->mutex);
int retval = ijkmp_prepare_async_l(mp);
pthread_mutex_unlock(&mp->mutex);
MPTRACE("ijkmp_prepare_async()=%d\n", retval);
return retval;
}
static int ijkmp_prepare_async_l(IjkMediaPlayer *mp)
{
assert(mp);
MPST_RET_IF_EQ(mp->mp_state, MP_STATE_IDLE);
// MPST_RET_IF_EQ(mp->mp_state, MP_STATE_INITIALIZED);
MPST_RET_IF_EQ(mp->mp_state, MP_STATE_ASYNC_PREPARING);
MPST_RET_IF_EQ(mp->mp_state, MP_STATE_PREPARED);
MPST_RET_IF_EQ(mp->mp_state, MP_STATE_STARTED);
MPST_RET_IF_EQ(mp->mp_state, MP_STATE_PAUSED);
MPST_RET_IF_EQ(mp->mp_state, MP_STATE_COMPLETED);
// MPST_RET_IF_EQ(mp->mp_state, MP_STATE_STOPPED);
MPST_RET_IF_EQ(mp->mp_state, MP_STATE_ERROR);
MPST_RET_IF_EQ(mp->mp_state, MP_STATE_END);
assert(mp->data_source);
ijkmp_change_state_l(mp, MP_STATE_ASYNC_PREPARING);
msg_queue_start(&mp->ffplayer->msg_queue);
// released in msg_loop
ijkmp_inc_ref(mp);
mp->msg_thread = SDL_CreateThreadEx(&mp->_msg_thread, ijkmp_msg_loop, mp, "ff_msg_loop");
// msg_thread is detached inside msg_loop
// TODO: 9 release weak_thiz if pthread_create() failed;
int retval = ffp_prepare_async_l(mp->ffplayer, mp->data_source);
if (retval < 0) {
ijkmp_change_state_l(mp, MP_STATE_ERROR);
return retval;
}
return 0;
}
依然逐步分析：
MPST_RET_IF_EQ(mp->mp_state, MP_STATE_IDLE);
// MPST_RET_IF_EQ(mp->mp_state, MP_STATE_INITIALIZED);
...
// MPST_RET_IF_EQ(mp->mp_state, MP_STATE_STOPPED);
MPST_RET_IF_EQ(mp->mp_state, MP_STATE_ERROR);
MPST_RET_IF_EQ(mp->mp_state, MP_STATE_END);
第一部分是用于状态机的检查，只有在 MP_STATE_INITIALIZED 和 MP_STATE_STOPPED 这两种状态时才能够执行 prepare_async。
ijkmp_change_state_l(mp, MP_STATE_ASYNC_PREPARING);
这里是改变状态为 MP_STATE_ASYNC_PREPAREING。方法详解
msg_queue_start(&mp->ffplayer->msg_queue);
在上面的方法详解中已经介绍过这个方法了。这个会激活 mp->ffplayer->msg_queue，并在 msg_queue 中加入一个类型为 FFP_MSG_FLUSH 的 Message。
mp->msg_thread = SDL_CreateThreadEx(&mp->_msg_thread, ijkmp_msg_loop, mp, "ff_msg_loop");
用于创建一个新的 Thread。方法详解
int retval = ffp_prepare_async_l(mp->ffplayer, mp->data_source);
这里是真正实现 prepare_async 逻辑的方法，在 ijkmedia/ijkplayer/ff_ffplay.c 中：
int ffp_prepare_async_l(FFPlayer *ffp, const char *file_name)
{
assert(ffp);
assert(!ffp->is);
assert(file_name);
if (av_stristart(file_name, "rtmp", NULL) ||
av_stristart(file_name, "rtsp", NULL)) {
// There is total different meaning for 'timeout' option in rtmp
av_log(ffp, AV_LOG_WARNING, "remove 'timeout' option for rtmp.\n");
av_dict_set(&ffp->format_opts, "timeout", NULL, 0);
}
/* there is a length limit in avformat */
if (strlen(file_name) + 1 > 1024) {
av_log(ffp, AV_LOG_ERROR, "%s too long url\n", __func__);
if (avio_find_protocol_name("ijklongurl:")) {
av_dict_set(&ffp->format_opts, "ijklongurl-url", file_name, 0);
file_name = "ijklongurl:";
}
}
av_log(NULL, AV_LOG_INFO, "===== versions =====\n");
ffp_show_version_str(ffp, "ijkplayer", ijk_version_info());
ffp_show_version_str(ffp, "FFmpeg", av_version_info());
ffp_show_version_int(ffp, "libavutil", avutil_version());
ffp_show_version_int(ffp, "libavcodec", avcodec_version());
ffp_show_version_int(ffp, "libavformat", avformat_version());
ffp_show_version_int(ffp, "libswscale", swscale_version());
ffp_show_version_int(ffp, "libswresample", swresample_version());
av_log(NULL, AV_LOG_INFO, "===== options =====\n");
ffp_show_dict(ffp, "player-opts", ffp->player_opts);
ffp_show_dict(ffp, "format-opts", ffp->format_opts);
ffp_show_dict(ffp, "codec-opts ", ffp->codec_opts);
ffp_show_dict(ffp, "sws-opts ", ffp->sws_dict);
ffp_show_dict(ffp, "swr-opts ", ffp->swr_opts);
av_log(NULL, AV_LOG_INFO, "===================\n");
av_opt_set_dict(ffp, &ffp->player_opts);
if (!ffp->aout) {
ffp->aout = ffpipeline_open_audio_output(ffp->pipeline, ffp);
if (!ffp->aout)
return -1;
}
#if CONFIG_AVFILTER
if (ffp->vfilter0) {
GROW_ARRAY(ffp->vfilters_list, ffp->nb_vfilters);
ffp->vfilters_list[ffp->nb_vfilters - 1] = ffp->vfilter0;
}
#endif
VideoState *is = stream_open(ffp, file_name, NULL);
if (!is) {
av_log(NULL, AV_LOG_WARNING, "ffp_prepare_async_l: stream_open failed OOM");
return EIJK_OUT_OF_MEMORY;
}
ffp->is = is;
ffp->input_filename = av_strdup(file_name);
return 0;
}
逐步分析：
if (av_stristart(file_name, "rtmp", NULL) ||
av_stristart(file_name, "rtsp", NULL)) {
...
}
av_stristart 的声明在 android/contrib/ffmpeg-arm64/libavutil/avstring.h 中：
/**
* Return non-zero if pfx is a prefix of str independent of case. If
* it is, *ptr is set to the address of the first character in str
* after the prefix.
*
* @param str input string
* @param pfx prefix to test
* @param ptr updated if the prefix is matched inside str
* @return non-zero if the prefix matches, zero otherwise
*/
int av_stristart(const char *str, const char *pfx, const char **ptr);
判断一个字符串的前缀是否是给定的字符串。在此处就是判断是 rtmp 或 rtsp。
// There is total different meaning for 'timeout' option in rtmp
av_log(ffp, AV_LOG_WARNING, "remove 'timeout' option for rtmp.\n");
av_dict_set(&ffp->format_opts, "timeout", NULL, 0);
通过注释可知，timeout 的选项对 rtmp 来说意义各别的不一样，所以就设置 timeout 项为 NULL。方法详解
/* there is a length limit in avformat */
if (strlen(file_name) + 1 > 1024) {
av_log(ffp, AV_LOG_ERROR, "%s too long url\n", __func__);
if (avio_find_protocol_name("ijklongurl:")) {
av_dict_set(&ffp->format_opts, "ijklongurl-url", file_name, 0);
file_name = "ijklongurl:";
}
}
对于 avformat 有长度限制为 1024，利用一个叫做 "ijklongurl" 的协议来对过长的文件名进行适配。
if (avio_find_protocol_name("ijklongurl:")) {
...
}
检查是否支持了 ijklongurl 协议。方法详解
av_dict_set(&ffp->format_opts, "ijklongurl-url", file_name, 0);
设置 "ijklongurl-url" 选项为 file_name。
file_name = "ijklongurl:";
再将 file_name 设为 "ijklongurl:"。可以推测是将文件名替换为 "ijklongurl:"，之后在播放时，从 ffp->format_opts 中找到真实的文件名，去请求播放。
av_log(NULL, AV_LOG_INFO, "===== versions =====\n");
ffp_show_version_str(ffp, "ijkplayer", ijk_version_info());
ffp_show_version_str(ffp, "FFmpeg", av_version_info());
ffp_show_version_int(ffp, "libavutil", avutil_version());
ffp_show_version_int(ffp, "libavcodec", avcodec_version());
ffp_show_version_int(ffp, "libavformat", avformat_version());
ffp_show_version_int(ffp, "libswscale", swscale_version());
ffp_show_version_int(ffp, "libswresample", swresample_version());
打印版本信息。
av_log(NULL, AV_LOG_INFO, "===== options =====\n");
ffp_show_dict(ffp, "player-opts", ffp->player_opts);
ffp_show_dict(ffp, "format-opts", ffp->format_opts);
ffp_show_dict(ffp, "codec-opts ", ffp->codec_opts);
ffp_show_dict(ffp, "sws-opts ", ffp->sws_dict);
ffp_show_dict(ffp, "swr-opts ", ffp->swr_opts);
av_log(NULL, AV_LOG_INFO, "===================\n");
打印选项信息。
av_opt_set_dict(ffp, &ffp->player_opts);
将 ffp->player_opts 设置到选项当中。方法详解
if (!ffp->aout) {
ffp->aout = ffpipeline_open_audio_output(ffp->pipeline, ffp);
if (!ffp->aout)
return -1;
}
对 ffp->aout 判空，若为空，则为其打开一个新的 Audio 输出管道。若创建失败，则返回 -1。创建 Audio 管道的方法详解。
#if CONFIG_AVFILTER
if (ffp->vfilter0) {
GROW_ARRAY(ffp->vfilters_list, ffp->nb_vfilters);
ffp->vfilters_list[ffp->nb_vfilters - 1] = ffp->vfilter0;
}
#endif
如果配制了 CONFIG_AVFILTER，则先判断 ffp->vfilter0 是否为空，若不为空，先为 ffp->vfilters_list 扩展长度为 ffp->nb_vfilters 的空间，之后再将 ffp->vfilter0 放入 ffp->nb_vfilters 的末尾。GROW_ARRAY 的声明在 extra/ffmpeg/cmdutils.h 中：
/**
* Realloc array to hold new_size elements of elem_size.
* Calls exit() on failure.
*
* @param array array to reallocate
* @param elem_size size in bytes of each element
* @param size new element count will be written here
* @param new_size number of elements to place in reallocated array
* @return reallocated array
*/
void *grow_array(void *array, int elem_size, int *size, int new_size);
#define GROW_ARRAY(array, nb_elems)\
array = grow_array(array, sizeof(*array), &nb_elems, nb_elems + 1)
用于扩展 array 的长度。
VideoState *is = stream_open(ffp, file_name, NULL);
打开数据流，得到状态。方法详解
if (!is) {
av_log(NULL, AV_LOG_WARNING, "ffp_prepare_async_l: stream_open failed OOM");
return EIJK_OUT_OF_MEMORY;
}
对 is 进行判空报错。
ffp->is = is;
ffp->input_filename = av_strdup(file_name);
return 0;
将返回的 is 状态设给 ffp，接着给 ffp->input_filename 设置文件名，最后返回 0。
至此，prepareAsync 就分析完毕。
通过 ijkmedia/ijkplayer/android/ijkplayer_jni.c 的 g_method 表，可以看到 _start 对应 native 方法：
static JNINativeMethod g_methods[] = {
...
{ "_start", "()V", (void *) IjkMediaPlayer_start },
...
}
static void
IjkMediaPlayer_start(JNIEnv *env, jobject thiz)
{
MPTRACE("%s\n", __func__);
IjkMediaPlayer *mp = jni_get_media_player(env, thiz);
JNI_CHECK_GOTO(mp, env, "java/lang/IllegalStateException", "mpjni: start: null mp", LABEL_RETURN);
ijkmp_start(mp);
LABEL_RETURN:
ijkmp_dec_ref_p(&mp);
}
逐步分析：
IjkMediaPlayer *mp = jni_get_media_player(env, thiz);
得到 IjkMediaPlayer 的引用。
ijkmp_start(mp);
开始播放，方法声明在 ijkmedia/ijkplayer/ijkplayer.h 中：
int ijkmp_start(IjkMediaPlayer *mp);
方法实现在 ijkmedia/ijkplayer/ijkplayer.c 中：
static int ikjmp_chkst_start_l(int mp_state)
{
MPST_RET_IF_EQ(mp_state, MP_STATE_IDLE);
MPST_RET_IF_EQ(mp_state, MP_STATE_INITIALIZED);
MPST_RET_IF_EQ(mp_state, MP_STATE_ASYNC_PREPARING);
// MPST_RET_IF_EQ(mp_state, MP_STATE_PREPARED);
// MPST_RET_IF_EQ(mp_state, MP_STATE_STARTED);
// MPST_RET_IF_EQ(mp_state, MP_STATE_PAUSED);
// MPST_RET_IF_EQ(mp_state, MP_STATE_COMPLETED);
MPST_RET_IF_EQ(mp_state, MP_STATE_STOPPED);
MPST_RET_IF_EQ(mp_state, MP_STATE_ERROR);
MPST_RET_IF_EQ(mp_state, MP_STATE_END);
return 0;
}
static int ijkmp_start_l(IjkMediaPlayer *mp)
{
assert(mp);
MP_RET_IF_FAILED(ikjmp_chkst_start_l(mp->mp_state));
ffp_remove_msg(mp->ffplayer, FFP_REQ_START);
ffp_remove_msg(mp->ffplayer, FFP_REQ_PAUSE);
ffp_notify_msg1(mp->ffplayer, FFP_REQ_START);
return 0;
}
int ijkmp_start(IjkMediaPlayer *mp)
{
assert(mp);
MPTRACE("ijkmp_start()\n");
pthread_mutex_lock(&mp->mutex);
int retval = ijkmp_start_l(mp);
pthread_mutex_unlock(&mp->mutex);
MPTRACE("ijkmp_start()=%d\n", retval);
return retval;
}
先看最开始的状态检测：
MPST_RET_IF_EQ(mp_state, MP_STATE_IDLE);
MPST_RET_IF_EQ(mp_state, MP_STATE_INITIALIZED);
MPST_RET_IF_EQ(mp_state, MP_STATE_ASYNC_PREPARING);
// MPST_RET_IF_EQ(mp_state, MP_STATE_PREPARED);
// MPST_RET_IF_EQ(mp_state, MP_STATE_STARTED);
// MPST_RET_IF_EQ(mp_state, MP_STATE_PAUSED);
// MPST_RET_IF_EQ(mp_state, MP_STATE_COMPLETED);
MPST_RET_IF_EQ(mp_state, MP_STATE_STOPPED);
MPST_RET_IF_EQ(mp_state, MP_STATE_ERROR);
MPST_RET_IF_EQ(mp_state, MP_STATE_END);
只有在视频处于 MP_STATE_PREPARED，MP_STATE_STARTED，MP_STATE_PAUSED 和 MP_STATE_COMPLETED 的状态下才可执行 start 方法。
ffp_remove_msg(mp->ffplayer, FFP_REQ_START);
ffp_remove_msg(mp->ffplayer, FFP_REQ_PAUSE);
ffp_notify_msg1(mp->ffplayer, FFP_REQ_START);
移除之前的状态 FFP_REQ_START 和 FFP_REQ_PAUSE，并发送状态消息 FFP_REQ_START。
接着在收到消息之后，之前讲过状态机方法，声明在 ijkmedia/ijkplayer/ijkplayer.h 中：
/* return < 0 if aborted, 0 if no packet and > 0 if packet. */
/* need to call msg_free_res for freeing the resouce obtained in msg */
int ijkmp_get_msg(IjkMediaPlayer *mp, AVMessage *msg, int block);
实现在 ijkmedia/ijkplayer/ijkplayer.c 中，现只看 case FFP_REQ_START: 部分：
/* need to call msg_free_res for freeing the resouce obtained in msg */
int ijkmp_get_msg(IjkMediaPlayer *mp, AVMessage *msg, int block)
{
...
while (1) {
...
case FFP_REQ_START:
MPTRACE("ijkmp_get_msg: FFP_REQ_START\n");
continue_wait_next_msg = 1;
pthread_mutex_lock(&mp->mutex);
if (0 == ikjmp_chkst_start_l(mp->mp_state)) {
// FIXME: 8 check seekable
if (mp->restart) {
if (mp->restart_from_beginning) {
av_log(mp->ffplayer, AV_LOG_DEBUG, "ijkmp_get_msg: FFP_REQ_START: restart from beginning\n");
retval = ffp_start_from_l(mp->ffplayer, 0);
if (retval == 0)
ijkmp_change_state_l(mp, MP_STATE_STARTED);
} else {
av_log(mp->ffplayer, AV_LOG_DEBUG, "ijkmp_get_msg: FFP_REQ_START: restart from seek pos\n");
retval = ffp_start_l(mp->ffplayer);
if (retval == 0)
ijkmp_change_state_l(mp, MP_STATE_STARTED);
}
mp->restart = 0;
mp->restart_from_beginning = 0;
} else {
av_log(mp->ffplayer, AV_LOG_DEBUG, "ijkmp_get_msg: FFP_REQ_START: start on fly\n");
retval = ffp_start_l(mp->ffplayer);
if (retval == 0)
ijkmp_change_state_l(mp, MP_STATE_STARTED);
}
}
pthread_mutex_unlock(&mp->mutex);
break;
case FFP_REQ_PAUSE:
MPTRACE("ijkmp_get_msg: FFP_REQ_PAUSE\n");
continue_wait_next_msg = 1;
pthread_mutex_lock(&mp->mutex);
if (0 == ikjmp_chkst_pause_l(mp->mp_state)) {
int pause_ret = ffp_pause_l(mp->ffplayer);
if (pause_ret == 0)
ijkmp_change_state_l(mp, MP_STATE_PAUSED);
}
pthread_mutex_unlock(&mp->mutex);
break;
...
if (continue_wait_next_msg) {
msg_free_res(msg);
continue;
}
return retval;
}
return -1;
}
continue_wait_next_msg = 1，标记状态机继续运行为 true。
pthread_mutex_lock(&mp->mutex);，加锁。
if (0 == ikjmp_chkst_start_l(mp->mp_state)) {，当前播放器的状态检查，同上。
if (mp->restart) {，判断是否是重播。
若是重播：
if (mp->restart_from_beginning) {，判断是否从头重播。
若是从头重播：
retval = ffp_start_from_l(mp->ffplayer, 0); 从头开始播放。方法详解
if (retval == 0)
ijkmp_change_state_l(mp, MP_STATE_STARTED);
若从头开始播放的返回码是无错的，那么改变播放器状态为已经开始。
else {
retval = ffp_start_l(mp->ffplayer);
if (retval == 0)
ijkmp_change_state_l(mp, MP_STATE_STARTED);
}
这里若不是从头重播，则直接调用开始播放的函数，并将播放器状态置为已经开始。
mp->restart = 0;
mp->restart_from_beginning = 0;
设置 restart 和 restart_from_beginning 状态为 false。
else {
av_log(mp->ffplayer, AV_LOG_DEBUG, "ijkmp_get_msg: FFP_REQ_START: start on fly\n");
retval = ffp_start_l(mp->ffplayer);
if (retval == 0)
ijkmp_change_state_l(mp, MP_STATE_STARTED);
}
如果不是重播，那么就直接播放，并将播放器的状态置为已经开始。
pthread_mutex_unlock(&mp->mutex); 解锁。