[FFmpeg-devel] [PATCH v2 1/3] avformat/flvenc: fix timestamp of key frame index

[FFmpeg-devel] [PATCH v2 1/3] avformat/flvenc: fix timestamp of key frame index

[Zhao Zhili]

From: Zhao Zhili <zhilizhao@tencent.com>

Firstly, the timestamps generated from framerate are inaccurate for
variable framerate mode.

Secondly, the timestamps always start from zero, while pts/dts can
start from nonzero. FLV demuxer rejects such index with message:
"Found invalid index entries, clearing the index".
---
 libavformat/flvenc.c                  | 5 +----
 tests/ref/fate/flv-add_keyframe_index | 2 +-
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/libavformat/flvenc.c b/libavformat/flvenc.c
index 770ca319ed..1c4ffb985a 100644
--- a/libavformat/flvenc.c
+++ b/libavformat/flvenc.c
@@ -104,7 +104,6 @@ typedef struct FLVContext {
     int64_t lastkeyframelocation_offset;
     int64_t lastkeyframelocation;
 
-    int acurframeindex;
     int64_t keyframes_info_offset;
 
     int64_t filepositions_count;
@@ -391,7 +390,6 @@ static void write_metadata(AVFormatContext *s, unsigned int ts)
     }
 
     if (flv->flags & FLV_ADD_KEYFRAME_INDEX) {
-        flv->acurframeindex = 0;
         flv->keyframe_index_size = 0;
 
         put_amf_string(pb, "hasVideo");
@@ -993,8 +991,7 @@ static int flv_write_packet(AVFormatContext *s, AVPacket *pkt)
         switch (par->codec_type) {
             case AVMEDIA_TYPE_VIDEO:
                 flv->videosize += (avio_tell(pb) - cur_offset);
-                flv->lasttimestamp = flv->acurframeindex / flv->framerate;
-                flv->acurframeindex++;
+                flv->lasttimestamp = pkt->dts / 1000.0;
                 if (pkt->flags & AV_PKT_FLAG_KEY) {
                     double ts = flv->lasttimestamp;
                     int64_t pos = cur_offset;
diff --git a/tests/ref/fate/flv-add_keyframe_index b/tests/ref/fate/flv-add_keyframe_index
index 39c4bed85a..6549170a68 100644
--- a/tests/ref/fate/flv-add_keyframe_index
+++ b/tests/ref/fate/flv-add_keyframe_index
@@ -1,4 +1,4 @@
-5f38d76da3ed4a5be06ca604c53666f2 *tests/data/fate/flv-add_keyframe_index.flv
+9f3d6de74f3329651a4c515c20cea00f *tests/data/fate/flv-add_keyframe_index.flv
 630192 tests/data/fate/flv-add_keyframe_index.flv
 #tb 0: 1/1000
 #media_type 0: video
-- 
2.34.1

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[FFmpeg-devel] [PATCH v2 2/3] avformat/flvdec: make key frame timestamps more accurate

[Zhao Zhili]

From: Zhao Zhili <zhilizhao@tencent.com>

There was an implicit cast from double to int64_t in time unit of
second.
---
 libavformat/flvdec.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
index 8dba92661b..10f0ea7736 100644
--- a/libavformat/flvdec.c
+++ b/libavformat/flvdec.c
@@ -146,9 +146,9 @@ static void add_keyframes_index(AVFormatContext *s)
     if (ffstream(stream)->nb_index_entries == 0) {
         for (i = 0; i < flv->keyframe_count; i++) {
             av_log(s, AV_LOG_TRACE, "keyframe filepositions = %"PRId64" times = %"PRId64"\n",
-                   flv->keyframe_filepositions[i], flv->keyframe_times[i] * 1000);
+                   flv->keyframe_filepositions[i], flv->keyframe_times[i]);
             av_add_index_entry(stream, flv->keyframe_filepositions[i],
-                flv->keyframe_times[i] * 1000, 0, 0, AVINDEX_KEYFRAME);
+                flv->keyframe_times[i], 0, 0, AVINDEX_KEYFRAME);
         }
     } else
         av_log(s, AV_LOG_WARNING, "Skipping duplicate index\n");
@@ -428,6 +428,7 @@ static int parse_keyframes_index(AVFormatContext *s, AVIOContext *ioc, int64_t m
            amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {
         int64_t **current_array;
         unsigned int arraylen;
+        int factor;
 
         // Expect array object in context
         if (avio_r8(ioc) != AMF_DATA_TYPE_ARRAY)
@@ -440,10 +441,12 @@ static int parse_keyframes_index(AVFormatContext *s, AVIOContext *ioc, int64_t m
         if       (!strcmp(KEYFRAMES_TIMESTAMP_TAG , str_val) && !times) {
             current_array = &times;
             timeslen      = arraylen;
+            factor = 1000;
         } else if (!strcmp(KEYFRAMES_BYTEOFFSET_TAG, str_val) &&
                    !filepositions) {
             current_array = &filepositions;
             fileposlen    = arraylen;
+            factor = 1;
         } else
             // unexpected metatag inside keyframes, will not use such
             // metadata for indexing
@@ -458,11 +461,9 @@ static int parse_keyframes_index(AVFormatContext *s, AVIOContext *ioc, int64_t m
             double d;
             if (avio_r8(ioc) != AMF_DATA_TYPE_NUMBER)
                 goto invalid;
-            d = av_int2double(avio_rb64(ioc));
+            d = av_int2double(avio_rb64(ioc)) * factor;
             if (isnan(d) || d < INT64_MIN || d > INT64_MAX)
                 goto invalid;
-            if (current_array == &times && (d <= INT64_MIN / 1000 || d >= INT64_MAX / 1000))
-                goto invalid;
             if (avio_feof(ioc))
                 goto invalid;
             current_array[0][i] = d;
@@ -478,7 +479,7 @@ static int parse_keyframes_index(AVFormatContext *s, AVIOContext *ioc, int64_t m
     if (timeslen == fileposlen && fileposlen>1 && max_pos <= filepositions[0]) {
         for (i = 0; i < FFMIN(2,fileposlen); i++) {
             flv->validate_index[i].pos = filepositions[i];
-            flv->validate_index[i].dts = times[i] * 1000;
+            flv->validate_index[i].dts = times[i];
             flv->validate_count        = i + 1;
         }
         flv->keyframe_times = times;
-- 
2.34.1

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[FFmpeg-devel] [PATCH v2 3/3] avformat/flvenc: fix shadowed variable ts

[Zhao Zhili]

From: Zhao Zhili <zhilizhao@tencent.com>

---
 libavformat/flvenc.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/libavformat/flvenc.c b/libavformat/flvenc.c
index 1c4ffb985a..5d574fa790 100644
--- a/libavformat/flvenc.c
+++ b/libavformat/flvenc.c
@@ -993,12 +993,9 @@ static int flv_write_packet(AVFormatContext *s, AVPacket *pkt)
                 flv->videosize += (avio_tell(pb) - cur_offset);
                 flv->lasttimestamp = pkt->dts / 1000.0;
                 if (pkt->flags & AV_PKT_FLAG_KEY) {
-                    double ts = flv->lasttimestamp;
-                    int64_t pos = cur_offset;
-
-                    flv->lastkeyframetimestamp = ts;
-                    flv->lastkeyframelocation = pos;
-                    ret = flv_append_keyframe_info(s, flv, ts, pos);
+                    flv->lastkeyframetimestamp = flv->lasttimestamp;
+                    flv->lastkeyframelocation = cur_offset;
+                    ret = flv_append_keyframe_info(s, flv, flv->lasttimestamp, cur_offset);
                     if (ret < 0)
                         goto fail;
                 }
-- 
2.34.1

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