FFmpeg

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Author	SHA1	Message	Date
Philip Langdale	9d89c8b3ac	matroskadec, matroskadec, srtenc: Read/Write duration for subtitles. After much discussion and back-and-forth, we reached the conclusion that matroska uses convergence_duration for subtitle duration because a 32bit value isn't large enough to store the duration if sub-micro-second timebases are used. Matroska may not be the only one that supports these timebases, but it's certainly the only one that ffmpeg attempts to support in this way. The long term solution that we seemed to reach was that if we encounter a matroska file with a sub-micro-second timebase, we should internally scale it up to at least micro-second, and then duration can be used normally. This suggests that on the encode side, we should not allow generation of files with sub-micro-second timebases, but that's a separate issue. That being a non-trivial change, and the subtitle interoperability breakage being very real, I'm re-submitting this small change for consideration. In this diff, we make sure that duration is populated by the matroska demuxer, and that convergence_duration is respected in matroskaenc and srtenc, but that duration is used otherwise. This ends up being a strict improvement - pipelines that use convergence duration are unchanged, and ones that are currently broken due to the duration mismatch will start working - except for the ones with the extreme timebases, but those were already broken. Signed-off-by: Philip Langdale <philipl@overt.org>	13 years ago
Philip Langdale	6057de19b5	srtenc: Add timing-less "subrip" encoder. Unsurprisingly, if a timing-less subrip decoder is desireable, an encoder is as well. With this in place, we can move on to remove the use of the old encoder/decoder with embedded timing and move all timing handling the (de)muxer where they belong. Signed-off-by: Philip Langdale <philipl@overt.org>	13 years ago
Nicolas George	9e63c30daa	lavf: add a real SRT muxer. This muxer supports CODEC_ID_SRT with the timestamps in the packet data and CODEC_ID_TEXT with the timestamps in the packet fields. Makes -scodec copy work from Matroska.	13 years ago

Author

SHA1

Message

Date

Philip Langdale

9d89c8b3ac

matroskadec, matroskadec, srtenc: Read/Write duration for subtitles.

After much discussion and back-and-forth, we reached the conclusion
that matroska uses convergence_duration for subtitle duration because
a 32bit value isn't large enough to store the duration if sub-micro-second
timebases are used. Matroska may not be the only one that supports these
timebases, but it's certainly the only one that ffmpeg attempts to support
in this way.

The long term solution that we seemed to reach was that if we encounter
a matroska file with a sub-micro-second timebase, we should internally
scale it up to at least micro-second, and then duration can be used
normally. This suggests that on the encode side, we should not allow
generation of files with sub-micro-second timebases, but that's a separate
issue.

That being a non-trivial change, and the subtitle interoperability breakage
being very real, I'm re-submitting this small change for consideration.

In this diff, we make sure that duration is populated by the matroska
demuxer, and that convergence_duration is respected in matroskaenc and
srtenc, but that duration is used otherwise. This ends up being a strict
improvement - pipelines that use convergence duration are unchanged, and
ones that are currently broken due to the duration mismatch will start
working - except for the ones with the extreme timebases, but those were
already broken.

Signed-off-by: Philip Langdale <philipl@overt.org>

13 years ago

Philip Langdale

6057de19b5

srtenc: Add timing-less "subrip" encoder.

Unsurprisingly, if a timing-less subrip decoder is desireable, an
encoder is as well. With this in place, we can move on to remove
the use of the old encoder/decoder with embedded timing and move
all timing handling the (de)muxer where they belong.

Signed-off-by: Philip Langdale <philipl@overt.org>

13 years ago

Nicolas George

9e63c30daa

lavf: add a real SRT muxer.

This muxer supports CODEC_ID_SRT with the timestamps in the packet data
and CODEC_ID_TEXT with the timestamps in the packet fields.

Makes -scodec copy work from Matroska.

13 years ago

5 Commits (a06f943f9d65a2e80536ee9e99d86e855c8ca8da)