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api-example: Try to avoid decoding incomplete frames

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Use a larger input audio buffer, refill it when it has less than 4 KB data
left.


backport r23323 by mstorsjo


Originally committed as revision 23377 to svn://svn.ffmpeg.org/ffmpeg/branches/0.6
This commit is contained in:
Reinhard Tartler 2010-05-29 14:20:05 +00:00
parent 9052b5b73b
commit 46ac6315fd
1 changed files with 28 additions and 19 deletions
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47
libavcodec/api-example.c
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@ -39,6 +39,8 @@
#include "libavutil/mathematics.h" #include "libavutil/mathematics.h"
#define INBUF_SIZE 4096 #define INBUF_SIZE 4096
#define AUDIO_INBUF_SIZE 20480
#define AUDIO_REFILL_THRESH 4096
/* /*
* Audio encoding example * Audio encoding example
@ -118,7 +120,7 @@ static void audio_decode_example(const char *outfilename, const char *filename)
int out_size, len; int out_size, len;
FILE *f, *outfile; FILE *f, *outfile;
uint8_t *outbuf; uint8_t *outbuf;
uint8_t inbuf[INBUF_SIZE + FF_INPUT_BUFFER_PADDING_SIZE]; uint8_t inbuf[AUDIO_INBUF_SIZE + FF_INPUT_BUFFER_PADDING_SIZE];
AVPacket avpkt; AVPacket avpkt;
av_init_packet(&avpkt); av_init_packet(&avpkt);
@ -155,25 +157,32 @@ static void audio_decode_example(const char *outfilename, const char *filename)
/* decode until eof */ /* decode until eof */
avpkt.data = inbuf; avpkt.data = inbuf;
for(;;) { avpkt.size = fread(inbuf, 1, AUDIO_INBUF_SIZE, f);
avpkt.size = fread(inbuf, 1, INBUF_SIZE, f);
if (avpkt.size == 0)
break;
avpkt.data = inbuf; while (avpkt.size > 0) {
while (avpkt.size > 0) { out_size = AVCODEC_MAX_AUDIO_FRAME_SIZE;
out_size = AVCODEC_MAX_AUDIO_FRAME_SIZE; len = avcodec_decode_audio3(c, (short *)outbuf, &out_size, &avpkt);
len = avcodec_decode_audio3(c, (short *)outbuf, &out_size, &avpkt); if (len < 0) {
if (len < 0) { fprintf(stderr, "Error while decoding\n");
fprintf(stderr, "Error while decoding\n"); exit(1);
exit(1); }
} if (out_size > 0) {
if (out_size > 0) { /* if a frame has been decoded, output it */
/* if a frame has been decoded, output it */ fwrite(outbuf, 1, out_size, outfile);
fwrite(outbuf, 1, out_size, outfile); }
} avpkt.size -= len;
avpkt.size -= len; avpkt.data += len;
avpkt.data += len; if (avpkt.size < AUDIO_REFILL_THRESH) {
/* Refill the input buffer, to avoid trying to decode
* incomplete frames. Instead of this, one could also use
* a parser, or use a proper container format through
* libavformat. */
memmove(inbuf, avpkt.data, avpkt.size);
avpkt.data = inbuf;
len = fread(avpkt.data + avpkt.size, 1,
AUDIO_INBUF_SIZE - avpkt.size, f);
if (len > 0)
avpkt.size += len;
} }
} }