[FFmpeg-cvslog] avformat/av1: Avoid using dynamic buffer when assembling av1c

[Andreas Rheinhardt]

ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinhardt at gmail.com> | Sun Jun 21 12:58:21 2020 +0200| [36fa84e7ac805a774820d06b3d58e4e875cb11c9] | committer: Andreas Rheinhardt

avformat/av1: Avoid using dynamic buffer when assembling av1c

Given that AV1 only has exactly one sequence header, it is unnecessary
to copy the content of said sequence header into an intermediate dynamic
buffer; instead the sequence header can be copied from where it is in
the input buffer.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=36fa84e7ac805a774820d06b3d58e4e875cb11c9
---

 libavformat/av1.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/libavformat/av1.c b/libavformat/av1.c
index 1e7a67d2f2..0cbffb1fd8 100644
--- a/libavformat/av1.c
+++ b/libavformat/av1.c
@@ -363,11 +363,11 @@ int ff_av1_parse_seq_header(AV1SequenceParameters *seq, const uint8_t *buf, int
 
 int ff_isom_write_av1c(AVIOContext *pb, const uint8_t *buf, int size)
 {
-    AVIOContext *seq_pb = NULL, *meta_pb = NULL;
+    AVIOContext *meta_pb;
     AV1SequenceParameters seq_params;
     PutBitContext pbc;
-    uint8_t header[4];
-    uint8_t *seq, *meta;
+    uint8_t header[4], *meta;
+    const uint8_t *seq;
     int64_t obu_size;
     int start_pos, type, temporal_id, spatial_id;
     int ret, nb_seq = 0, seq_size, meta_size;
@@ -375,12 +375,9 @@ int ff_isom_write_av1c(AVIOContext *pb, const uint8_t *buf, int size)
     if (size <= 0)
         return AVERROR_INVALIDDATA;
 
-    ret = avio_open_dyn_buf(&seq_pb);
-    if (ret < 0)
-        return ret;
     ret = avio_open_dyn_buf(&meta_pb);
     if (ret < 0)
-        goto fail;
+        return ret;
 
     while (size > 0) {
         int len = parse_obu_header(buf, size, &obu_size, &start_pos,
@@ -401,7 +398,8 @@ int ff_isom_write_av1c(AVIOContext *pb, const uint8_t *buf, int size)
             if (ret < 0)
                 goto fail;
 
-            avio_write(seq_pb, buf, len);
+            seq      = buf;
+            seq_size = len;
             break;
         case AV1_OBU_METADATA:
             if (!obu_size) {
@@ -417,8 +415,7 @@ int ff_isom_write_av1c(AVIOContext *pb, const uint8_t *buf, int size)
         buf  += len;
     }
 
-    seq_size  = avio_get_dyn_buf(seq_pb, &seq);
-    if (!seq_size) {
+    if (!nb_seq) {
         ret = AVERROR_INVALIDDATA;
         goto fail;
     }
@@ -447,7 +444,6 @@ int ff_isom_write_av1c(AVIOContext *pb, const uint8_t *buf, int size)
         avio_write(pb, meta, meta_size);
 
 fail:
-    ffio_free_dyn_buf(&seq_pb);
     ffio_free_dyn_buf(&meta_pb);
 
     return ret;