FFmpeg

Commit Graph

Author	SHA1	Message	Date
Clément Bœsch	860a081058	avcodec/assenc: fix potential overread.	11 years ago
Clément Bœsch	7c1a002c78	subtitles: introduce ASS codec id and use it. Currently, we have a AV_CODEC_ID_SSA, which matches the way the ASS/SSA markup is muxed in a standalone .ass/.ssa file. This means the AVPacket data starts with a "Dialogue:" string, followed by a timing information (start and end of the event as string) and a trailing CRLF after each line. One packet can contain several lines. We'll refer to this layout as "SSA" or "SSA lines". In matroska, this markup is not stored as such: it has no "Dialogue:" prefix, it contains a ReadOrder field, the timing information is not in the payload, and it doesn't contain the trailing CRLF. See [1] for more info. We'll refer to this layout as "ASS". Since we have only one common codec for both formats, the matroska demuxer is constructing an AVPacket following the "SSA lines" format. This causes several problems, so it was decided to change this into clean ASS packets. Some insight about what is changed or unchanged in this commit: CODECS ------ - the decoding process still writes "SSA lines" markup inside the ass fields of the subtitles rectangles (sub->rects[n]->ass), which is still the current common way of representing decoded subtitles markup. It is meant to change later. - new ASS codec id: AV_CODEC_ID_ASS (which is different from the legacy AV_CODEC_ID_SSA) - lavc/assdec: the "ass" decoder is renamed into "ssa" (instead of "ass") for consistency with the codec id and allows to add a real ass decoder. This ass decoder receives clean ASS lines (so it starts with a ReadOrder, is followed by the Layer, etc). We make sure this is decoded properly in a new ass-line rectangle of the decoded subtitles (the ssa decoder OTOH is doing a simple straightforward copy). Using the packet timing instead of data string makes sure the ass-line now contains the appropriate timing. - lavc/assenc: just like the ass decoder, the "ssa" encoder is renamed into "ssa" (instead of "ass") for consistency with the codec id, and allows to add a real "ass" encoder. One important thing about this encoder is that it only supports one ass rectangle: we could have put several dialogue events in the AVPacket (separated by a \0 for instance) but this would have cause trouble for the muxer which needs not only the start time, but also the duration: typically, you have merged events with the same start time (stored in the AVPacket->pts) but a different duration. At the moment, only the matroska do the merge with the SSA-line codec. We will need to make sure all the decoders in the future can't add more than one rectangle (and only one Dialogue line in it obviously). FORMATS ------- - lavf/assenc: the .ass/.ssa muxer can take both SSA and ASS packets. In the case of ASS packets as input, it adds the timing based on the AVPacket pts and duration, and mux it with "Dialogue:", trailing CRLF, etc. - lavf/assdec: unchanged; it currently still only outputs SSA-lines packets. - lavf/mkv: the demuxer can now output ASS packets without the need of any "SSA-lines" reconstruction hack. It will become the default at next libavformat bump, and the SSA support will be dropped from the demuxer. The muxer can take ASS packets since it's muxed normally, and still supports the old SSA packets. All the SSA support and hacks in Matroska code will be dropped at next lavf bump. [1]: http://www.matroska.org/technical/specs/subtitles/ssa.html	12 years ago
Clément Bœsch	36e61e24e7	lavc: add ff_bprint_to_extradata() helper and use it. This commit also makes sure the extradata and subtitle_header are NUL terminated, without taking into account the trailing '\0' in account in the size. At the same time, it should fix 'warning: dereferencing type-punned pointer will break strict-aliasing rules' warning for compilers who don't consider uint8_t and char compatibles.	12 years ago
Anton Khirnov	466b39efaf	lavc: replace AVCodecContext.encode with subtitle-specific callback AVCodecContext.encode is currently used only for subtitles, encode2 is used for audio and video.	12 years ago
Martin Storsjö	1d9c2dc89a	Don't include common.h from avutil.h Signed-off-by: Martin Storsjö <martin@martin.st>	12 years ago
Anton Khirnov	36ef5369ee	Replace all CODEC_ID_* with AV_CODEC_ID_*	12 years ago
Diego Biurrun	0177b7d23a	Improve descriptiveness of a number of codec and container long names	12 years ago
Mans Rullgard	2912e87a6c	Replace FFmpeg with Libav in licence headers Signed-off-by: Mans Rullgard <mans@mansr.com>	14 years ago
Diego Elio Pettenò	e7e2df27f8	Add ff_ prefix to data symbols of encoders, decoders, hwaccel, parsers, bsf. None of these symbols should be accessed directly, so declare them as hidden. Signed-off-by: Mans Rullgard <mans@mansr.com> (cherry picked from commit `d36beb3f69`)	14 years ago
Diego Elio Pettenò	d36beb3f69	Add ff_ prefix to data symbols of encoders, decoders, hwaccel, parsers, bsf. None of these symbols should be accessed directly, so declare them as hidden. Signed-off-by: Mans Rullgard <mans@mansr.com>	14 years ago
Aurelien Jacobs	5952be07dc	add missing files in previous commit (ASS encoder and decoder) Originally committed as revision 25747 to svn://svn.ffmpeg.org/ffmpeg/trunk	14 years ago

15 Commits (8ca170a78ab6e50f44d27d8a6b4ad7ba1ed81f0c)