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flvdec: read index stored in the 'keyframes' tag.

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'keyframes' metatag is not part of the standard, it is just
convention to use such kind of metatag information for indexing.
Structure is following, it allows to have it inconsistent:
keyframes:
 times (array):
  time0 (num)
  time1 (num)
  time2 (num)
 filepositions (array)
  position0 (num)
  position1 (num)

Signed-off-by: Anton Khirnov <anton@khirnov.net>
This commit is contained in:
Kharkov Alexander 2011-03-18 08:26:51 +01:00 committed by Anton Khirnov
parent 9dd94f8379
commit cb7e2c1ca8
1 changed files with 66 additions and 0 deletions
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66
libavformat/flvdec.c
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@ -31,6 +31,10 @@
#include "avio_internal.h"
#include "flv.h"
#define KEYFRAMES_TAG "keyframes"
#define KEYFRAMES_TIMESTAMP_TAG "times"
#define KEYFRAMES_BYTEOFFSET_TAG "filepositions"
typedef struct {
int wrong_dts; ///< wrong dts due to negative cts
} FLVContext;
@ -125,6 +129,64 @@ static int amf_get_string(AVIOContext *ioc, char *buffer, int buffsize) {
return length;
}
static int parse_keyframes_index(AVFormatContext *s, AVIOContext *ioc, AVStream *vstream, int64_t max_pos) {
unsigned int arraylen = 0, timeslen = 0, fileposlen = 0, i;
double num_val;
char str_val[256];
int64_t *times = NULL;
int64_t *filepositions = NULL;
int ret = 0;
while (avio_tell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {
int64_t* current_array;
// Expect array object in context
if (avio_r8(ioc) != AMF_DATA_TYPE_ARRAY)
break;
arraylen = avio_rb32(ioc);
/*
* Expect only 'times' or 'filepositions' sub-arrays in other case refuse to use such metadata
* for indexing
*/
if (!strcmp(KEYFRAMES_TIMESTAMP_TAG, str_val) && !times) {
if (!(times = av_mallocz(sizeof(*times) * arraylen))) {
ret = AVERROR(ENOMEM);
goto finish;
}
timeslen = arraylen;
current_array = times;
} else if (!strcmp(KEYFRAMES_BYTEOFFSET_TAG, str_val) && !filepositions) {
if (!(filepositions = av_mallocz(sizeof(*filepositions) * arraylen))) {
ret = AVERROR(ENOMEM);
goto finish;
}
fileposlen = arraylen;
current_array = filepositions;
} else // unexpected metatag inside keyframes, will not use such metadata for indexing
break;
for (i = 0; i < arraylen && avio_tell(ioc) < max_pos - 1; i++) {
if (avio_r8(ioc) != AMF_DATA_TYPE_NUMBER)
goto finish;
num_val = av_int2dbl(avio_rb64(ioc));
current_array[i] = num_val;
}
}
if (timeslen == fileposlen)
for(i = 0; i < arraylen; i++)
av_add_index_entry(vstream, filepositions[i], times[i]*1000, 0, 0, AVINDEX_KEYFRAME);
else
av_log(s, AV_LOG_WARNING, "Invalid keyframes object, skipping.\n");
finish:
av_freep(&times);
av_freep(&filepositions);
avio_seek(ioc, max_pos, SEEK_SET);
return ret;
}
static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream *vstream, const char *key, int64_t max_pos, int depth) {
AVCodecContext *acodec, *vcodec;
AVIOContext *ioc;
@ -149,6 +211,10 @@ static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream *vst
case AMF_DATA_TYPE_OBJECT: {
unsigned int keylen;
if (!strcmp(KEYFRAMES_TAG, key) && depth == 1)
if (parse_keyframes_index(s, ioc, vstream, max_pos) < 0)
return -1;
while(avio_tell(ioc) < max_pos - 2 && (keylen = avio_rb16(ioc))) {
avio_skip(ioc, keylen); //skip key string
if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)