@@ -437,28 +437,26 @@ static void mkv_add_seekhead_entry(MatroskaMuxContext *mkv, uint32_t elementid,
/**
* Write the SeekHead to the file at the location reserved for it
- * and seek back to the initial position. When error_on_seek_failure
+ * and seek to destpos afterwards. When error_on_seek_failure
* is not set, failure to seek to the position designated for the
- * SeekHead is not considered an error; failure to seek back afterwards
- * is always an error.
+ * SeekHead is not considered an error; failure to seek to destpos
+ * afterwards is always an error.
*
* @return 0 on success, < 0 on error.
*/
static int mkv_write_seekhead(AVIOContext *pb, MatroskaMuxContext *mkv,
- int error_on_seek_failure)
+ int error_on_seek_failure, int64_t destpos)
{
AVIOContext *dyn_cp;
mkv_seekhead *seekhead = &mkv->seekhead;
ebml_master seekentry;
- int64_t currentpos, remaining, ret64;
+ int64_t remaining, ret64;
int i, ret;
- currentpos = avio_tell(pb);
-
if ((ret64 = avio_seek(pb, seekhead->filepos, SEEK_SET)) < 0) {
if (error_on_seek_failure)
return ret64;
- goto seek_back;
+ goto seek;
}
ret = start_ebml_master_crc32(pb, &dyn_cp, mkv, MATROSKA_ID_SEEKHEAD);
@@ -482,8 +480,8 @@ static int mkv_write_seekhead(AVIOContext *pb, MatroskaMuxContext *mkv,
remaining = seekhead->filepos + seekhead->reserved_size - avio_tell(pb);
put_ebml_void(pb, remaining);
-seek_back:
- if ((ret64 = avio_seek(pb, currentpos, SEEK_SET)) < 0)
+seek:
+ if ((ret64 = avio_seek(pb, destpos, SEEK_SET)) < 0)
return ret64;
return 0;
@@ -1929,7 +1927,7 @@ static int mkv_write_header(AVFormatContext *s)
return ret;
if (!(s->pb->seekable & AVIO_SEEKABLE_NORMAL) && !mkv->is_live) {
- ret = mkv_write_seekhead(pb, mkv, 0);
+ ret = mkv_write_seekhead(pb, mkv, 0, avio_tell(pb));
if (ret < 0)
return ret;
}
@@ -2533,16 +2531,16 @@ static int mkv_write_trailer(AVFormatContext *s)
mkv_add_seekhead_entry(mkv, MATROSKA_ID_CUES, cuespos);
}
- ret = mkv_write_seekhead(pb, mkv, 1);
+ currentpos = avio_tell(pb);
+
+ ret = mkv_write_seekhead(pb, mkv, 1, mkv->info_pos);
if (ret < 0)
return ret;
// update the duration
av_log(s, AV_LOG_DEBUG, "end duration = %" PRIu64 "\n", mkv->duration);
- currentpos = avio_tell(pb);
avio_seek(mkv->info_bc, mkv->duration_offset, SEEK_SET);
put_ebml_float(mkv->info_bc, MATROSKA_ID_DURATION, mkv->duration);
- avio_seek(pb, mkv->info_pos, SEEK_SET);
end_ebml_master_crc32(pb, &mkv->info_bc, mkv);
// write tracks master
When writing the SeekHead (a form of index) at the end of the muxing process, mkv_write_seekhead() would first seek to the position where the SeekHead ought to be written, then write it there and seek back to the original position afterwards. Which means: To the end of the file. Afterwards, a seek to the beginning of the file is performed to update further values. This of course means that the second seek in mkv_write_seekhead() was unnecessary. This has been changed: A new parameter was added to mkv_write_seekhead() containing the destination for the second seek, effectively eliminating the seek to the end of the file after writing the SeekHead. Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com> --- libavformat/matroskaenc.c | 26 ++++++++++++-------------- 1 file changed, 12 insertions(+), 14 deletions(-)