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Code Issues Releases Activity

latm: Add a probe function

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This commit is contained in:
Luca Barbato 2014-04-26 20:32:47 +02:00
parent de69aedf99
commit f66d0c57b1
1 changed files with 53 additions and 0 deletions
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53
libavformat/rawdec.c
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@ -27,6 +27,7 @@
#include "libavutil/opt.h"
#include "libavutil/parseutils.h"
#include "libavutil/pixdesc.h"
#include "libavutil/intreadwrite.h"
#define RAW_PACKET_SIZE 1024
@ -109,9 +110,61 @@ const AVOption ff_rawvideo_options[] = {
};
#if CONFIG_LATM_DEMUXER
#define LOAS_SYNC_WORD 0x2b7
static int latm_read_probe(AVProbeData *p)
{
int max_frames = 0, first_frames = 0;
int fsize, frames;
uint8_t *buf0 = p->buf;
uint8_t *buf2;
uint8_t *buf;
uint8_t *end = buf0 + p->buf_size - 3;
buf = buf0;
for (; buf < end; buf = buf2 + 1) {
buf2 = buf;
for (frames = 0; buf2 < end; frames++) {
uint32_t header = AV_RB24(buf2);
if ((header >> 13) != LOAS_SYNC_WORD) {
if (buf != buf0) {
// Found something that isn't a LOAS header, starting
// from a position other than the start of the buffer.
// Discard the count we've accumulated so far since it
// probably was a false positive.
frames = 0;
}
break;
}
fsize = (header & 0x1FFF) + 3;
if (fsize < 7)
break;
buf2 += fsize;
}
max_frames = FFMAX(max_frames, frames);
if (buf == buf0)
first_frames = frames;
}
if (first_frames >= 3)
return AVPROBE_SCORE_EXTENSION + 1;
else if (max_frames > 100)
return AVPROBE_SCORE_EXTENSION;
else if (max_frames >= 3)
return AVPROBE_SCORE_EXTENSION / 2;
else if (max_frames >= 1)
return 1;
else
return 0;
}
AVInputFormat ff_latm_demuxer = {
.name = "latm",
.long_name = NULL_IF_CONFIG_SMALL("raw LOAS/LATM"),
.read_probe = latm_read_probe,
.read_header = ff_raw_audio_read_header,
.read_packet = ff_raw_read_partial_packet,
.flags = AVFMT_GENERIC_INDEX,