Use it only on subtitle CuePoints.
With proper demuxer/splitter support this should improve the display
of subtitles right after seeking to a given point in the stream.
Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Files won't validate with mkvalidtor if these two elements are missing.
Use a const "Lavf" string that wont change with library version bumps.
Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
The muxer has been creating files with v4 elements for some time now,
and especially now that we can mux non-experimental Opus files, reporting
the DocTypeVersion as 2 is not correct.
Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
In order to represent the codec delay accurately in Matroska, a
new element CodecDelay has been introduced. It contains the
overall delay added by the codec in nanoseconds. This patch adds
support for muxing CodecDelay value in the container.
Matroska spec for CodecDelay element can be found here:
http://matroska.org/technical/specs/index.html#CodecDelay
Signed-off-by: Vignesh Venkatasubramanian <vigneshv@google.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Support for end trimming Opus in Matroska is implemented by using
the DiscardPadding container element in the Block data. The last
chunk is stored as a Block instead of SimpleBlock and the
trimming information is stored and used to discard samples that
were padded by the Opus codec. This patch adds support for muxing
DiscardPadding element into the container with appropriate value.
Matroska spec for the DiscardPadding element can be found here:
http://matroska.org/technical/specs/index.html#DiscardPadding
Signed-off-by: Vignesh Venkatasubramanian <vigneshv@google.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This fixes a bunch of possible overread in avformat with the idiom p +=
strcspn(p, "\n") + 1 (strcspn() can focus on the trailing '\0' if no
'\n' is found, so the +1 leads to an overread).
Note on lavf/matroskaenc: no extra subtitles.o Makefile dependency is
added because only the header is required for ff_subtitles_next_line().
Note on lavf/mpsubdec: code gets slightly complex to avoid an infinite
loop in the probing since there is no more forced increment.
This allows creation of frame accurate chapter marks from sources like
DVD and BD where the precise chapter location is not known until the
chapter mark has been reached during reading.
Signed-off-by: Anton Khirnov <anton@khirnov.net>
The element was only being written when the value == 1. But the default
value of this element is 1, so this has no useful effect. This element
needs to be written when the value == 0.
Signed-off-by: Anton Khirnov <anton@khirnov.net>
Allow emitting the current cluster that is being written before
starting a new one, simplifying how to figure out where clusters
are positioned in the output stream (for live streaming).
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
In order to encapsuate Opus in Matroska, there is a new element
that has been added to the Matroska Spec, SeekPreRoll. It has the
duration in nanoseconds that has to be decoded before every seek.
Spec: http://matroska.org/technical/specs/index.html#SeekPreRoll
Proposal for encapsulateing Opus in Matroska:
http://wiki.xiph.org/MatroskaOpus
Signed-off-by: Vignesh Venkatasubramanian <vigneshv@google.com>
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This is a minimal change to matroskaenc that implements CueRelativePosition in the output.
Most players will probably ignore this additional information, but it is in the
matroska spec, and it'd be nice to be able to make use of it.
Signed-off-by: Bernt Habermeier <bernt@wulfram.com>
Tested-by: wm4 <nfxjfg@googlemail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This also fixes the case where negative chapter ids where input
And fixes the case where remuxing from mkv changed chapter ids
Found-by: Luca Barbato
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Tags must have at least one SimpleTag element to be spec conformant.
Updated lavf-mkv and seek-lavf-mkv FATE references as the tests were affected by
this.
Fixes ticket #2785
Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
The Matroska muxer now allows WebVTT subtitle tracks to be written
while in WebM muxing mode.
WebVTT subtitle tracks have four kinds: "subtitles", "captions",
"descriptions", and "metadata". Each text track kind has a distinct
Mastroska CodecID and track type, as described in the temporal
metadata guidelines here:
http://wiki.webmproject.org/webm-metadata/temporal-metadata/webvtt-in-webm
When the stream has codec id AV_CODEC_ID_WEBVTT, the stream packet is
serialized per the temporal metadata guidelines cited above. The
WebVTT cue is written as a Matroska block group. The block frame
comprises the WebVTT cue id, followed by the cue settings, followed by
the cue text. (The block timestamp is synthesized from the cue
timestamp.)
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This patch adds support for muxing VP8 Alpha Files. The Alpha channel data is
placed in BlockAdditional element of the matroska container. More information
& exact spec on how this is implemented can be found here: http://goo.gl/wCP1y
Signed-off-by: Vignesh Venkatasubramanian <vigneshv@google.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
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
Avoid to write more than one cuepoint per track and PTS in
mkv_write_cues(). This avoids a later assertion failure on "(bytes >=
needed_bytes)" in put_ebml_num() called from end_ebml_master(), in case
there are several cuepoints per track with the same PTS.
This may happen with files containing packets with duplicated PTS in the
same track.
Jan Gerber
Michael Niedermayer
James Almer
Alexandra Khirnova
Vignesh Venkatasubramanian
Clément Bœsch
Paul B Mahol
John Stebbins
Martin Storsjö
Luca Barbato
Bernie Habermeier
Fabian Neundorf
Alexis Ballier
Matthew Heaney
Tudor Suciu
Rafaël Carré
Anton Khirnov
Nicolas George
Clément Bœsch
Stefano Sabatini
Carl Eugen Hoyos