Leaking this private structure opens up the possibility that it may
be re-used when parsing later packets in the stream. This is
problematic if the later packets are not the same codec type (e.g.
private allocated during Vorbis parsing, but later packets are Opus
and the private is assumed to be the oggopus_private type in
opus_header()).
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
Currently, AVStream contains an embedded AVCodecContext instance, which
is used by demuxers to export stream parameters to the caller and by
muxers to receive stream parameters from the caller. It is also used
internally as the codec context that is passed to parsers.
In addition, it is also widely used by the callers as the decoding (when
demuxer) or encoding (when muxing) context, though this has been
officially discouraged since Libav 11.
There are multiple important problems with this approach:
- the fields in AVCodecContext are in general one of
* stream parameters
* codec options
* codec state
However, it's not clear which ones are which. It is consequently
unclear which fields are a demuxer allowed to set or a muxer allowed to
read. This leads to erratic behaviour depending on whether decoding or
encoding is being performed or not (and whether it uses the AVStream
embedded codec context).
- various synchronization issues arising from the fact that the same
context is used by several different APIs (muxers/demuxers,
parsers, bitstream filters and encoders/decoders) simultaneously, with
there being no clear rules for who can modify what and the different
processes being typically delayed with respect to each other.
- avformat_find_stream_info() making it necessary to support opening
and closing a single codec context multiple times, thus
complicating the semantics of freeing various allocated objects in the
codec context.
Those problems are resolved by replacing the AVStream embedded codec
context with a newly added AVCodecParameters instance, which stores only
the stream parameters exported by the demuxers or read by the muxers.
This commit introduces a parser for the current bitstream produced by
Daala. It currently bears a large similarity with Theora, another
codec produced by Xiph. While likely to change in the future, its basic
format of packet parsing should remain fairly identical with its current
structure.
Once the bitstream freezes, there are a few probable simplifications
that could be made. Also, the current version (major, minor and micro)
is stuck at zero so it's unusable as a way to warn about possible
incompatibilities. This will change once the bitstream freezes,
however until then this file is strictly targeting the current git
master of the reference encoder, libdaala.
This file was developed independently at the same time by both myself
and Vittorio Giovara, who used libav as a starting point. For fairness,
and to prevent confusion and allegations, his name has been added to the
copyright in the license header as well, and vice versa.
The read_packet callback passes a pointer to a stack-allocated AVPacket.
Attempting to free it with av_free() makes no sense.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Adding support for end trimming Opus embedded in Ogg container.
Signed-Off By: Vignesh Venkatasubramanian <vigneshv@google.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Seeking in certain broken files would cause ogg_read_timestamp
to fail because ogg_packet would go into a state where all packets
of stream 1 would be discarded until the end of the stream.
Bug-Id: 553
CC: libav-stable@libav.org
Signed-off-by: Jan Gerber <j@v2v.cc>
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
Attempting to re-parse the headers at demuxer level is a
pandora box the way its done currently.
This allows full reconfiguration of vorbis streams
Fixes Ticket2117
Fixes Ticket2121
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This prevents inconsistencies leading to out of array accesses.
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Chris Cunningham
Lou Logan
Anton Khirnov
Hendrik Leppkes
Rostislav Pehlivanov
Michael Niedermayer
Vittorio Giovara
Luca Barbato
Federico Tomassetti
Michael Niedermayer
wm4
James Almer
Schenk, Michael
Ben Boeckel
Dale Curtis
Nicolas George
Vignesh Venkatasubramanian
Alexandra Khirnova
Reimar Döffinger
Paul B Mahol