This is mainly about improving legibility of the code and getting rid of
overlong lines by using variables for st->codecpar instead of accessing
the codecparameters via st->codecpar->.
Also, some code has been moved to better fitting places.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
This commit removes data that is only used during smacker_read_header()
from the demuxer's context and replaces the data that is used by local
variables. The other data is completely dropped.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
The Smacker demuxer currently parses several fields that indicate
how many audio streams a file contains. This data is parsed and stored
into arrays in the demuxer's context and although the data is used only
to initialize the audio streams, it is kept for the whole lifetime of
the demuxer.
This has been changed: The data is used directly to create
the audio streams and no longer kept at all.
This also simplifies error handling in case adding a new stream fails:
Several arrays which until now have been allocated between parsing the
data determining how many audio streams to create and actually creating
them would need to be freed in this case. Now the streams are created
first, so freeing is no longer an issue.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
The Smacker demuxer reads four consecutive 32bit values from the file
header into its demux context (as four uint32_t), converting it to
native endianness in the process and then writing these four values
later (after extradata has been allocated) to extradata as four 32bit
values (converting to little endian in the process).
This commit changes this: The stream and the extradata are allocated
earlier, so that the data destined for extradata can be read directly
into extradata.
Furthermore, given that these values are not needed for demuxing itself
they are now no longer kept as part of the demuxing context.
Finally, a check regarding the number of frames has been moved up,
too, in order to exit early before unnecessarily allocating the
stream and the extradata.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
It is not uncommon to find code where the caller thinks to know better
what the return value should be than the callee. E.g. something like
"if (av_new_packet(pkt, size) < 0) return AVERROR(ENOMEM);". This commit
changes several instances of this to instead forward the actual error.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
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.
When av_reallocp fails, the associated variables that keep track of
the number of elements in the array (and in some cases, the
separate number of allocated elements) need to be reset.
Not all of these might technically be needed, but it's better to
reset them if in doubt, to make sure variables don't end up
conflicting.
Signed-off-by: Martin Storsjö <martin@martin.st>
Andreas Rheinhardt
Steven Liu
Carl Eugen Hoyos
Michael Niedermayer
Sean McGovern
Anton Khirnov
Vittorio Giovara
Michael Niedermayer
James Almer
Diego Biurrun
Paul B Mahol
Martin Storsjö
Alexandra Khirnova
Kostya Shishkov
Justin Ruggles
Ronald S. Bultje
Laurent Aimar
Mans Rullgard
Clément Bœsch