- 23 Feb, 2016 1 commit
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Anton Khirnov authored
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.
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- 10 Mar, 2015 2 commits
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Martin Storsjö authored
By making sure we at each time only have one pointer set, either a local variable or one in the context, we avoid potential double frees in the cleanup routines. If chain->rtp_ctx is set, it is closed by calling avformat_write_trailer, but that shouldn't be called unless avformat_write_header succeeded. This issue was pointed out by Andreas Cadhalpun. Signed-off-by:
Martin Storsjö <martin@martin.st>
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Martin Storsjö authored
This fixes a typo from 8e32b1f0. Signed-off-by:
Martin Storsjö <martin@martin.st>
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- 24 Feb, 2015 1 commit
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Martin Storsjö authored
Signed-off-by:
Martin Storsjö <martin@martin.st>
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- 19 Dec, 2014 1 commit
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Martin Storsjö authored
Since the mpegts muxer now can handle being called with a NULL AVIOContext, we don't need to try to allocate one before calling write_trailer. Signed-off-by:
Martin Storsjö <martin@martin.st>
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- 18 Dec, 2014 1 commit
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Martin Storsjö authored
Since this structurally is quite different from normal RTP (multiple streams are muxed into one single mpegts stream, which is packetized into one single RTP session), it is kept as a separate muxer. Since this structurally also behaves differently than normal RTP, all of the other muxers that do chained RTP muxing (rtsp, sap, mp4) would need to be updated similarly to handle this - in particular, creating one single rtp_mpegts muxer for the whole presentation instead of one rtp muxer per stream. Signed-off-by:
Martin Storsjö <martin@martin.st>
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