avformat/vorbiscomment: Switch to AVIOContext from bytestream API

Up until now ff_vorbiscomment_write() used the bytestream API to write
VorbisComments. Therefore the caller had to provide a sufficiently large
buffer to write the output.

Yet two of the three callers (namely the FLAC and the Matroska muxer)
actually want the output to be written via an AVIOContext; therefore
they allocated buffers of the right size just for this purpose (i.e.
they get freed immediately afterwards). Only the Ogg muxer actually
wants a buffer. But given that it is easy to wrap a buffer into an
AVIOContext this commit changes ff_vorbiscomment_write() to use an
AVIOContext for its output.

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

1 files changed, 4 insertions, 14 deletions

diff --git a/libavformat/flacenc.c b/libavformat/flacenc.c
index 0e88e18355..b947a3b067 100644
--- a/libavformat/flacenc.c
+++ b/libavformat/flacenc.c
@@ -29,7 +29,6 @@
 #include "id3v2.h"
 #include "internal.h"
 #include "vorbiscomment.h"
-#include "libavcodec/bytestream.h"
 
 
 typedef struct FlacMuxerContext {
@@ -62,25 +61,16 @@ static int flac_write_block_comment(AVIOContext *pb, AVDictionary **m,
 {
     const char *vendor = bitexact ? "ffmpeg" : LIBAVFORMAT_IDENT;
     int64_t len;
-    uint8_t *p, *p0;
 
     ff_metadata_conv(m, ff_vorbiscomment_metadata_conv, NULL);
 
     len = ff_vorbiscomment_length(*m, vendor, NULL, 0);
     if (len >= ((1<<24) - 4))
         return AVERROR(EINVAL);
-    p0 = av_malloc(len+4);
-    if (!p0)
-        return AVERROR(ENOMEM);
-    p = p0;
-
-    bytestream_put_byte(&p, last_block ? 0x84 : 0x04);
-    bytestream_put_be24(&p, len);
-    ff_vorbiscomment_write(&p, *m, vendor, NULL, 0);
-
-    avio_write(pb, p0, len+4);
-    av_freep(&p0);
-    p = NULL;
+
+    avio_w8(pb, last_block ? 0x84 : 0x04);
+    avio_wb24(pb, len);
+    ff_vorbiscomment_write(pb, *m, vendor, NULL, 0);
 
     return 0;
 }