From: Kharkov Alexander <[email protected]>
'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)
---
libavformat/flvdec.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 66 insertions(+), 0 deletions(-)
diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
index 2152f7d..972b4d9 100644
--- a/libavformat/flvdec.c
+++ b/libavformat/flvdec.c
@@ -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(×);
+ 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)
--
1.7.4.1
_______________________________________________
libav-devel mailing list
[email protected]
https://lists.libav.org/mailman/listinfo/libav-devel
