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.
Originally, AVFormatContext and a metadata dict were provided to ff_vorbis_comment(),
but this presented issues if an AVStream was being updated or the metadata on
AVFormatContext wasn't actually being updated. To remedy this, ff_vorbis_stream_comment()
explicitly updates a stream's metadata and sets any necessary flags.
ff_vorbis_comment() does not modify any flags, and any calls to it that update
AVFormatContext's metadata (just a single call) must also update
AVFormatContext.event_flags after detecting any metadata changes to the provided
dictionary, as signaled by a positive return value.
Signed-off-by: Anton Khirnov <anton@khirnov.net>
Setting seek_preroll value in AVCodecContext for Opus streams
embedded in ogg container.
Signed-off-by: Vignesh Venkatasubramanian <vigneshv@google.com>
Reviewed-by: Nicolas George <george@nsup.org>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Fix timestamp calculation for code 3 Ogg Opus packets with less than
2 bytes in the last segment (e.g. packet length 255 or 256).
A sample that would seek incorrectly in ffplay can be created with:
ffmpeg -i in.wav -b:a 34k -vbr off -frame_duration 60 out.opus
and libopus 1.1
Also do not read past the end of the buffer when a packet has length 0.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Regression since 39d11d599c
os->pduration would be wrongly assigned a negative value on invalid packets
instead of aborting.
Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Opus Pre Skip is exported in AVCodecContext->delay similar to how
it is done for matroska. Doing the same for ogg too.
Signed-off-by: Vignesh Venkatasubramanian <vigneshv@google.com>
Reviewed-by: Nicolas George <george@nsup.org>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Line comes from ecab1c7741
and was not merged previously
Thanks-to: Nicolas George <george@nsup.org>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
* commit 'ecab1c77410f023b437c6ed3a3281be8f039e574':
oggdec: add support for Opus in Ogg demuxing
Conflicts:
Changelog
libavformat/oggparseopus.c
libavformat/version.h
See: e62fd6619f
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Re-wording a log message that's no longer true and changing its
severity level to debug.
Signed-off by: Vignesh Venkatasubramanian <vigneshv@google.com>
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>
