flvdec: read audio sample size and channels metadata

This is needed in order for the FLV demuxer not to detect a codec change when
using the "flv_metadata" option.

libavformat/flvdec.c

@@ -400,7 +400,7 @@ static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream *vst
  acodec = astream ? astream->codec : NULL;
  vcodec = vstream ? vstream->codec : NULL;
 
- if (amf_type == AMF_DATA_TYPE_NUMBER) {
+ if (amf_type == AMF_DATA_TYPE_NUMBER || amf_type == AMF_DATA_TYPE_BOOL) {
  if (!strcmp(key, "duration"))
  s->duration = num_val * AV_TIME_BASE;
  else if (!strcmp(key, "videodatarate") && vcodec && 0 <= (int)(num_val * 1024.0))
@@ -422,6 +422,13 @@ static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream *vst
  } else
  if (!strcmp(key, "audiosamplerate") && acodec) {
  acodec->sample_rate = num_val;
+ } else if (!strcmp(key, "audiosamplesize") && acodec) {
+ acodec->bits_per_coded_sample = num_val;
+ } else if (!strcmp(key, "stereo") && acodec) {
+ acodec->channels = num_val + 1;
+ acodec->channel_layout = acodec->channels == 2 ?
+ AV_CH_LAYOUT_STEREO :
+ AV_CH_LAYOUT_MONO;
  } else
  if (!strcmp(key, "width") && vcodec) {
  vcodec->width = num_val;