[FFmpeg-devel] [PATCH 4/4] avformat/matroskaenc: Reuse dynamic buffer

[Andreas Rheinhardt]

Avoids some allocations.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
---
 libavformat/matroskaenc.c | 30 ++++++++++--------------------
 1 file changed, 10 insertions(+), 20 deletions(-)

diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index f1385c6b21..60647869ca 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -220,7 +220,8 @@ typedef struct MatroskaMuxContext {
      * to write the length field of EBML Masters.
      * Every user has to reset the buffer after using it and
      * different uses may not overlap. It is currently used in
-     * mkv_write_tag(). */
+     * mkv_write_tag(), in mkv_assemble_cues() as well as in
+     * mkv_check_new_extra_data(). */
     AVIOContext        *tmp_bc;
 
     AVPacket           *cur_audio_pkt;
@@ -929,17 +930,10 @@ static int mkv_add_cuepoint(MatroskaMuxContext *mkv, int stream, int64_t ts,
     return 0;
 }
 
-static int mkv_assemble_cues(AVStream **streams, AVIOContext *dyn_cp,
+static int mkv_assemble_cues(AVStream **streams, AVIOContext *dyn_cp, AVIOContext *cuepoint,
                              const mkv_cues *cues, mkv_track *tracks, int num_tracks,
                              uint64_t offset)
 {
-    AVIOContext *cuepoint;
-    int ret;
-
-    ret = avio_open_dyn_buf(&cuepoint);
-    if (ret < 0)
-        return ret;
-
     for (mkv_cuepoint *entry = cues->entries, *end = entry + cues->num_entries;
          entry < end;) {
         uint64_t pts = entry->pts;
@@ -969,14 +963,13 @@ static int mkv_assemble_cues(AVStream **streams, AVIOContext *dyn_cp,
             end_ebml_master(cuepoint, track_positions);
         } while (++entry < end && entry->pts == pts);
         size = avio_get_dyn_buf(cuepoint, &buf);
-        if ((ret = cuepoint->error) < 0)
-            break;
+        if (cuepoint->error < 0)
+            return cuepoint->error;
         put_ebml_binary(dyn_cp, MATROSKA_ID_POINTENTRY, buf, size);
         ffio_reset_dyn_buf(cuepoint);
     }
-    ffio_free_dyn_buf(&cuepoint);
 
-    return ret;
+    return 0;
 }
 
 static int put_xiph_codecpriv(AVFormatContext *s, AVIOContext *pb,
@@ -2648,23 +2641,20 @@ static int mkv_check_new_extra_data(AVFormatContext *s, const AVPacket *pkt)
     //        See https://bugs.chromium.org/p/aomedia/issues/detail?id=2012
     case AV_CODEC_ID_AV1:
         if (side_data_size && mkv->track.bc && !par->extradata_size) {
-            AVIOContext *dyn_cp;
+            AVIOContext *const dyn_cp = mkv->tmp_bc;
             uint8_t *codecpriv;
             int codecpriv_size;
-            ret = avio_open_dyn_buf(&dyn_cp);
-            if (ret < 0)
-                return ret;
             ff_isom_write_av1c(dyn_cp, side_data, side_data_size, 1);
             codecpriv_size = avio_get_dyn_buf(dyn_cp, &codecpriv);
             if ((ret = dyn_cp->error) < 0 ||
                 !codecpriv_size && (ret = AVERROR_INVALIDDATA)) {
-                ffio_free_dyn_buf(&dyn_cp);
+                ffio_reset_dyn_buf(dyn_cp);
                 return ret;
             }
             avio_seek(mkv->track.bc, track->codecpriv_offset, SEEK_SET);
             // Do not write the OBUs as we don't have space saved for them
             put_ebml_binary(mkv->track.bc, MATROSKA_ID_CODECPRIVATE, codecpriv, 4);
-            ffio_free_dyn_buf(&dyn_cp);
+            ffio_reset_dyn_buf(dyn_cp);
             ret = ff_alloc_extradata(par, side_data_size);
             if (ret < 0)
                 return ret;
@@ -2891,7 +2881,7 @@ redo_cues:
         if (ret < 0)
             return ret;
 
-        ret = mkv_assemble_cues(s->streams, cues, &mkv->cues,
+        ret = mkv_assemble_cues(s->streams, cues, mkv->tmp_bc, &mkv->cues,
                                 mkv->tracks, s->nb_streams, offset);
         if (ret < 0) {
             ffio_free_dyn_buf(&cues);
-- 
2.34.1