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examples: demuxing: do partial audio packet decoding

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This assumes one audio packet is decoded one time. This is not true:
packets can be partially decoded. Then you have to "adjust" the packet
and pass the undecoded part of the packet to the decode function again.
This commit is contained in:
wm4 2013-07-18 15:45:35 +02:00 committed by Stefano Sabatini
parent 25ffaf5277
commit 06b269dacb
1 changed files with 16 additions and 3 deletions
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19
doc/examples/demuxing.c
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@ -60,6 +60,7 @@ static int audio_frame_count = 0;
static int decode_packet(int *got_frame, int cached) static int decode_packet(int *got_frame, int cached)
{ {
int ret = 0; int ret = 0;
int decoded = pkt.size;
if (pkt.stream_index == video_stream_idx) { if (pkt.stream_index == video_stream_idx) {
/* decode video frame */ /* decode video frame */
@ -91,6 +92,11 @@ static int decode_packet(int *got_frame, int cached)
fprintf(stderr, "Error decoding audio frame\n"); fprintf(stderr, "Error decoding audio frame\n");
return ret; return ret;
} }
/* Some audio decoders decode only part of the packet, and have to be
* called again with the remainder of the packet data.
* Sample: fate-suite/lossless-audio/luckynight-partial.shn
* Also, some decoders might over-read the packet. */
decoded = FFMIN(ret, pkt.size);
if (*got_frame) { if (*got_frame) {
printf("audio_frame%s n:%d nb_samples:%d pts:%s\n", printf("audio_frame%s n:%d nb_samples:%d pts:%s\n",
@ -121,7 +127,7 @@ static int decode_packet(int *got_frame, int cached)
} }
} }
return ret; return decoded;
} }
static int open_codec_context(int *stream_idx, static int open_codec_context(int *stream_idx,
@ -293,8 +299,15 @@ int main (int argc, char **argv)
/* read frames from the file */ /* read frames from the file */
while (av_read_frame(fmt_ctx, &pkt) >= 0) { while (av_read_frame(fmt_ctx, &pkt) >= 0) {
decode_packet(&got_frame, 0); AVPacket orig_pkt = pkt;
av_free_packet(&pkt); do {
ret = decode_packet(&got_frame, 0);
if (ret < 0)
break;
pkt.data += ret;
pkt.size -= ret;
} while (pkt.size > 0);
av_free_packet(&orig_pkt);
} }
/* flush cached frames */ /* flush cached frames */