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, 5 deletions

diff --git a/libavformat/vorbiscomment.h b/libavformat/vorbiscomment.h
index af9bd75cd7..7cacd0b2a0 100644
--- a/libavformat/vorbiscomment.h
+++ b/libavformat/vorbiscomment.h
@@ -38,18 +38,17 @@ int64_t ff_vorbiscomment_length(const AVDictionary *m, const char *vendor_string
                                 AVChapter **chapters, unsigned int nb_chapters);
 
 /**
- * Write a VorbisComment into a buffer. The buffer, p, must have enough
- * data to hold the whole VorbisComment. The minimum size required can be
- * obtained by passing the same AVDictionary and vendor_string to
+ * Write a VorbisComment into an AVIOContext. The output size can be obtained
+ * in advance by passing the same chapters, AVDictionary and vendor_string to
  * ff_vorbiscomment_length()
  *
- * @param p The buffer in which to write.
+ * @param pb The AVIOContext to write the output.
  * @param m The metadata struct to write.
  * @param vendor_string The vendor string to write.
  * @param chapters The chapters to write.
  * @param nb_chapters The number of chapters to write.
  */
-int ff_vorbiscomment_write(uint8_t **p, const AVDictionary *m,
+int ff_vorbiscomment_write(AVIOContext *pb, const AVDictionary *m,
                            const char *vendor_string,
                            AVChapter **chapters, unsigned int nb_chapters);