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.
Previously only the edit_rate of material_track was checked.
If it's negative, it causes assertion failures in av_rescale_rnd.
Reviewed-by: Tim Nicholson <nichot20-at-yahoo.com@ffmpeg.org>
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
According to S377M, segmented frame layout is identical to separate
field layout except that the two fields are taken from a single scan
of the incoming image, ie: they are coincident in time. Thus the
resulting frame is progressive.
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
* commit '6448f15af02f2c3cf0df8cb8237957e426041f2d':
mxfdec: Fix the error handling for when strftime fails
Merged-by: Michael Niedermayer <michaelni@gmx.at>
While the native jpeg2000 decoder can determine pixel format correctly
from the codestream, libopenjpeg wrapper cannot. To make sure that
the output is correct when using libopenjpeg to decode digital
cinema files, we do detection from the metadata included in the MXF
wrapper.
If the container has "JPEG 2000 Coding Parameters" metadata element
with Rsiz value set to one of digital cinema profiles, we can safely
assume that the given input file is DCI compliant, therefore the
pixel format should be XYZ.
Reviewed-by: Tomas Härdin <tomas.hardin@codemill.se>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
I think this is a better way to deal with single frame essence data then my
previous way.
Reviewed-by: Tomas Härdin <tomas.hardin@codemill.se>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Based on discussion and patch from
"[FFmpeg-devel] [PATCH]Do not ask for mxf samples with unknown field dominance"
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
FooterPartition offset specified in RIP takes precedence over any value written
in PartitionPacks. This fixes the same issue f06f6da tries to fix without
introducing an extra variable.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
