threads: default to automatic thread count detection

zhengxj91 · Dec 31, 2011 · e4e3025 · e4e3025
1 parent c11b92b
commit e4e3025
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Showing 4 changed files with 18 additions and 6 deletions.
diff --git a/Changelog b/Changelog
@@ -6,6 +6,7 @@ version <next>:
 
 - Indeo 4 decoder
 - SMJPEG demuxer
+- Automatic thread count based on detection number of (available) CPU cores
 
 
 version 0.8_beta1:

diff --git a/libavcodec/options.c b/libavcodec/options.c
@@ -370,7 +370,7 @@ static const AVOption options[]={
 {"float", NULL, 0, AV_OPT_TYPE_CONST, {.dbl = FF_AA_FLOAT }, INT_MIN, INT_MAX, V|D, "aa"},
 #endif
 {"qns", "quantizer noise shaping", OFFSET(quantizer_noise_shaping), AV_OPT_TYPE_INT, {.dbl = DEFAULT }, INT_MIN, INT_MAX, V|E},
-{"threads", NULL, OFFSET(thread_count), AV_OPT_TYPE_INT, {.dbl = 1 }, 0, INT_MAX, V|E|D, "threads"},
+{"threads", NULL, OFFSET(thread_count), AV_OPT_TYPE_INT, {.dbl = 0 }, 0, INT_MAX, V|E|D, "threads"},
 {"auto", "detect a good number of threads", 0, AV_OPT_TYPE_CONST, {.dbl = 0 }, INT_MIN, INT_MAX, V|E|D, "threads"},
 {"me_threshold", "motion estimaton threshold", OFFSET(me_threshold), AV_OPT_TYPE_INT, {.dbl = DEFAULT }, INT_MIN, INT_MAX, V|E},
 {"mb_threshold", "macroblock threshold", OFFSET(mb_threshold), AV_OPT_TYPE_INT, {.dbl = DEFAULT }, INT_MIN, INT_MAX, V|E},

diff --git a/libavcodec/version.h b/libavcodec/version.h
@@ -22,7 +22,7 @@
 
 #define LIBAVCODEC_VERSION_MAJOR 53
 #define LIBAVCODEC_VERSION_MINOR 32
-#define LIBAVCODEC_VERSION_MICRO 0
+#define LIBAVCODEC_VERSION_MICRO 1
 
 #define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
  LIBAVCODEC_VERSION_MINOR, \

diff --git a/libavformat/utils.c b/libavformat/utils.c
@@ -2268,9 +2268,14 @@ int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
  int i, count, ret, read_size, j;
  AVStream *st;
  AVPacket pkt1, *pkt;
+ AVDictionary *one_thread_opt = NULL;
  int64_t old_offset = avio_tell(ic->pb);
  int orig_nb_streams = ic->nb_streams; // new streams might appear, no options for those
 
+ /* this function doesn't flush the decoders, so force thread count
+ * to 1 to fix behavior when thread count > number of frames in the file */
+ av_dict_set(&one_thread_opt, "threads", "1", 0);
+
  for(i=0;i<ic->nb_streams;i++) {
  AVCodec *codec;
  st = ic->streams[i];
@@ -2300,12 +2305,13 @@ int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
  /* Ensure that subtitle_header is properly set. */
  if (st->codec->codec_type == AVMEDIA_TYPE_SUBTITLE
  && codec && !st->codec->codec)
- avcodec_open2(st->codec, codec, options ? &options[i] : NULL);
+ avcodec_open2(st->codec, codec, options ? &options[i] : &one_thread_opt);
 
  //try to just open decoders, in case this is enough to get parameters
  if(!has_codec_parameters(st->codec)){
  if (codec && !st->codec->codec)
- avcodec_open2(st->codec, codec, options ? &options[i] : NULL);
+ avcodec_open2(st->codec, codec, options ? &options[i]
+ : &one_thread_opt);
  }
  }
 
@@ -2444,7 +2450,8 @@ int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
  least one frame of codec data, this makes sure the codec initializes
  the channel configuration and does not only trust the values from the container.
  */
- try_decode_frame(st, pkt, (options && i < orig_nb_streams )? &options[i] : NULL);
+ try_decode_frame(st, pkt, (options && i < orig_nb_streams )? &options[i]
+ : &one_thread_opt);
 
  st->codec_info_nb_frames++;
  count++;
@@ -2549,8 +2556,12 @@ int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
 #endif
 
  find_stream_info_err:
- for (i=0; i < ic->nb_streams; i++)
+ for (i=0; i < ic->nb_streams; i++) {
+ if (ic->streams[i]->codec)
+ ic->streams[i]->codec->thread_count = 0;
  av_freep(&ic->streams[i]->info);
+ }
+ av_dict_free(&one_thread_opt);
  return ret;
 }