2018-05-19 23:48 GMT+02:00, James Almer <jamr...@gmail.com>: > On 5/19/2018 6:31 PM, Michael Niedermayer wrote: >> On Fri, May 18, 2018 at 11:15:04AM -0700, Aman Gupta wrote: >>> From: Aman Gupta <a...@tmm1.net> >>> >>> These fields will allow the mpegts demuxer to expose details about >>> the PMT/program which created the AVProgram and its AVStreams. >>> >>> In mpegts, a PMT which advertises streams has a version number >>> which can be incremented at any time. When the version changes, >>> the pids which correspond to each of it's streams can also change. >>> >>> Since ffmpeg creates a new AVStream per pid by default, an API user >>> needs the ability to (a) detect when the PMT changed, and (b) tell >>> which AVStream were added to replace earlier streams. >>> >>> This has been a long-standing issue with ffmpeg's handling of mpegts >>> streams with PMT changes, and I found two related patches in the wild >>> that attempt to solve the same problem. >>> >>> The first is in MythTV's ffmpeg fork, where they added a >>> void (*streams_changed)(void*); to AVFormatContext and call it from >>> their fork of the mpegts demuxer whenever the PMT changes. >>> >>> The second was proposed by XBMC in >>> https://ffmpeg.org/pipermail/ffmpeg-devel/2012-December/135036.html, >>> where they created a new AVMEDIA_TYPE_DATA stream with id=0 and >>> attempted to send packets to it whenever the PMT changed. >>> >>> Signed-off-by: Aman Gupta <a...@tmm1.net> >>> --- >>> doc/APIchanges | 4 ++++ >>> libavformat/avformat.h | 8 ++++++++ >>> libavformat/utils.c | 1 + >>> libavformat/version.h | 2 +- >>> 4 files changed, 14 insertions(+), 1 deletion(-) >>> >>> diff --git a/doc/APIchanges b/doc/APIchanges >>> index befa58c84a..a592073ca5 100644 >>> --- a/doc/APIchanges >>> +++ b/doc/APIchanges >>> @@ -15,6 +15,10 @@ libavutil: 2017-10-21 >>> >>> API changes, most recent first: >>> >>> +2018-05-xx - xxxxxxxxxx - lavf 58.15.100 - avformat.h >>> + Add pmt_version field to AVProgram >>> + Add program_num, pmt_version, pmt_stream_idx to AVStream >>> + >>> 2018-05-xx - xxxxxxxxxx - lavf 58.14.100 - avformat.h >>> Add AV_DISPOSITION_STILL_IMAGE >>> >>> diff --git a/libavformat/avformat.h b/libavformat/avformat.h >>> index 6dce88fad5..ade918f99c 100644 >>> --- a/libavformat/avformat.h >>> +++ b/libavformat/avformat.h >>> @@ -1103,6 +1103,13 @@ typedef struct AVStream { >>> */ >>> int stream_identifier; >>> >>> + /** >>> + * Details of the MPEG-TS program which created this stream. >>> + */ >>> + int program_num; >>> + int pmt_version; >>> + int pmt_stream_idx; >>> + >>> int64_t interleaver_chunk_size; >>> int64_t interleaver_chunk_duration; >>> >> >> These are added below the "All fields below this line are not part of the >> public API." >> This contradicts the addition to APIChanges > > If these don't need to be accessed by the API user then I'd rather keep > them here than moving them to the public section. Just remove the > APIChanges entry. > Same thing with the AVStream pmt_version field. If direct access is not > needed for it, then it should be moved below the public notice. > > These fields seem pretty specific to one demuxer so ideally they > shouldn't be public in case changes to them and the implementation are > ever needed.
Reading the original submission above, isn't the whole point of the patch to add public symbols to help downstream with real-world issues? Carl Eugen _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
