[FFmpeg-devel] [PATCH] avformat/fivdec: cached keyframes before video or audio stream was created

[Xinzheng Zhang]

---
 libavformat/flvdec.c | 84 ++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 69 insertions(+), 15 deletions(-)

diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
index 2bf1e05..82b9f83 100644
--- a/libavformat/flvdec.c
+++ b/libavformat/flvdec.c
@@ -61,6 +61,12 @@ typedef struct FLVContext {
 
     int broken_sizes;
     int sum_flv_tag_size;
+
+    int vhead_exists;
+    int ahead_exists;
+    int keyframe_count;
+    int64_t *keyframe_times;
+    int64_t *keyframe_filepositions;
 } FLVContext;
 
 static int probe(AVProbeData *p, int live)
@@ -92,6 +98,42 @@ static int live_flv_probe(AVProbeData *p)
     return probe(p, 1);
 }
 
+static void add_keyframes_index(AVFormatContext *s)
+{
+    FLVContext *flv           = s->priv_data;
+    AVStream *current_stream  = NULL;
+    AVStream *vstream         = NULL;
+    AVStream *astream         = NULL;
+    unsigned int i,j                ;
+
+    for (i = 0; i< s->nb_streams; i++) {
+        if (s->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
+            vstream = s->streams[i];
+        } else if (s->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
+            astream = s->streams[i];
+        }
+    }
+
+    AVStream *streams[2] = {vstream, astream};
+    for (i = 0; i < 2; i++) {
+        current_stream = streams[i];
+        if (current_stream && current_stream->nb_index_entries==0) {
+            for (j = 0; j < flv->keyframe_count; j++) {
+                av_add_index_entry(current_stream, flv->keyframe_filepositions[j], flv->keyframe_times[j] * 1000,
+                                   0, 0, AVINDEX_KEYFRAME);
+            }
+        }
+    }
+
+    // free keyframe index only if all expected streams have been created
+    if (((vstream && vstream->nb_index_entries>0) || !flv->vhead_exists) &&
+        ((astream && astream->nb_index_entries>0) || !flv->ahead_exists)) {
+        av_freep(&flv->keyframe_times);
+        av_freep(&flv->keyframe_filepositions);
+        flv->keyframe_count = 0;
+    }
+}
+
 static AVStream *create_stream(AVFormatContext *s, int codec_type)
 {
     AVStream *st = avformat_new_stream(s, NULL);
@@ -104,6 +146,7 @@ static AVStream *create_stream(AVFormatContext *s, int codec_type)
         s->ctx_flags &= ~AVFMTCTX_NOHEADER;
 
     avpriv_set_pts_info(st, 32, 1, 1000); /* 32 bit pts in ms */
+    add_keyframes_index(s);
     return st;
 }
 
@@ -305,8 +348,7 @@ 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)
+static int parse_keyframes_index(AVFormatContext *s, AVIOContext *ioc, int64_t max_pos)
 {
     FLVContext *flv       = s->priv_data;
     unsigned int timeslen = 0, fileposlen = 0, i;
@@ -316,7 +358,7 @@ static int parse_keyframes_index(AVFormatContext *s, AVIOContext *ioc,
     int ret                = AVERROR(ENOSYS);
     int64_t initial_pos    = avio_tell(ioc);
 
-    if (vstream->nb_index_entries>0) {
+    if (flv->keyframe_count > 0) {
         av_log(s, AV_LOG_WARNING, "Skipping duplicate index\n");
         return 0;
     }
@@ -324,6 +366,10 @@ static int parse_keyframes_index(AVFormatContext *s, AVIOContext *ioc,
     if (s->flags & AVFMT_FLAG_IGNIDX)
         return 0;
 
+    av_freep(&flv->keyframe_times);
+    av_freep(&flv->keyframe_filepositions);
+    flv->keyframe_count = 0;
+
     while (avio_tell(ioc) < max_pos - 2 &&
            amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {
         int64_t **current_array;
@@ -366,17 +412,17 @@ static int parse_keyframes_index(AVFormatContext *s, AVIOContext *ioc,
             break;
         }
     }
-
     if (timeslen == fileposlen && fileposlen>1 && max_pos <= filepositions[0]) {
-        for (i = 0; i < fileposlen; i++) {
-            av_add_index_entry(vstream, filepositions[i], times[i] * 1000,
-                               0, 0, AVINDEX_KEYFRAME);
-            if (i < 2) {
-                flv->validate_index[i].pos = filepositions[i];
-                flv->validate_index[i].dts = times[i] * 1000;
-                flv->validate_count        = i + 1;
-            }
+        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_count        = i + 1;
         }
+        flv->keyframe_times = times;
+        flv->keyframe_filepositions = filepositions;
+        flv->keyframe_count = timeslen;
+        times = NULL;
+        filepositions = NULL;
     } else {
 invalid:
         av_log(s, AV_LOG_WARNING, "Invalid keyframes object, skipping.\n");
@@ -418,12 +464,14 @@ static int amf_parse_object(AVFormatContext *s, AVStream *astream,
         }
         break;
     case AMF_DATA_TYPE_OBJECT:
-        if ((vstream || astream) && key &&
+        if (key &&
             ioc->seekable &&
             !strcmp(KEYFRAMES_TAG, key) && depth == 1)
-            if (parse_keyframes_index(s, ioc, vstream ? vstream : astream,
+            if (parse_keyframes_index(s, ioc,
                                       max_pos) < 0)
                 av_log(s, AV_LOG_ERROR, "Keyframe index parsing failed\n");
+            else
+                add_keyframes_index(s);
 
         while (avio_tell(ioc) < max_pos - 2 &&
                amf_get_string(ioc, str_val, sizeof(str_val)) > 0)
@@ -631,9 +679,13 @@ static int flv_read_header(AVFormatContext *s)
 {
     FLVContext *flv = s->priv_data;
     int offset;
+    int flags;
 
     avio_skip(s->pb, 4);
-    avio_r8(s->pb); // flags
+    flags = avio_r8(s->pb); // flags
+
+    flv->vhead_exists = flags & FLV_HEADER_FLAG_HASVIDEO;
+    flv->ahead_exists = flags & FLV_HEADER_FLAG_HASAUDIO;
 
     s->ctx_flags |= AVFMTCTX_NOHEADER;
 
@@ -653,6 +705,8 @@ static int flv_read_close(AVFormatContext *s)
     FLVContext *flv = s->priv_data;
     for (i=0; i<FLV_STREAM_TYPE_NB; i++)
         av_freep(&flv->new_extradata[i]);
+    av_freep(&flv->keyframe_times);
+    av_freep(&flv->keyframe_filepositions);
     return 0;
 }
 
-- 
2.6.4 (Apple Git-63)