On 01.11.2016 05:09, James Almer wrote: > On 10/31/2016 11:32 PM, James Almer wrote: >> Fixes remuxing apng streams coming from the apng demuxer. >> This is a regression since 97792e85c338d129342f5812e2a52048373e57d6. >> >> Signed-off-by: James Almer <jamr...@gmail.com> >> --- >> libavformat/apngenc.c | 7 +++++++ >> 1 file changed, 7 insertions(+) >> >> diff --git a/libavformat/apngenc.c b/libavformat/apngenc.c >> index e5e8aa9..2b88dcc 100644 >> --- a/libavformat/apngenc.c >> +++ b/libavformat/apngenc.c >> @@ -101,6 +101,13 @@ static int apng_write_header(AVFormatContext >> *format_context) >> avio_wb64(format_context->pb, PNGSIG); >> // Remaining headers are written when they are copied from the encoder >> >> + apng->extra_data = >> av_mallocz(format_context->streams[0]->codecpar->extradata_size + >> AV_INPUT_BUFFER_PADDING_SIZE); >> + if (!apng->extra_data) >> + return AVERROR(ENOMEM); >> + apng->extra_data_size = >> format_context->streams[0]->codecpar->extradata_size; >> + memcpy(apng->extra_data, >> format_context->streams[0]->codecpar->extradata, >> + format_context->streams[0]->codecpar->extradata_size); >> + > > Alternatively we could just go back to the first version of Andreas' patch, > where the codecpar extradata was overwritten by the updated one from the > packet side data, and get rid of the private context buffer. > > I assumed keeping the codecpar extradata intact was the correct behavior, > based on the avcodec.h documentation and since AVCodecParameters is an > intermediary struct meant to pass parameters between de/muxers and > de/encoders, but it seems the mov and flv muxers just overwrite it. I'm not > sure if it makes a difference at all. > > Any opinions?
What I like about the approach of using the private extra_data context buffer is that is is quite obvious where it is set. On the other hand the codecpar extradata can be set anywhere, which makes it difficult to understand/debug. The very bug this patch would fix is an excellent example of that. So I'd rather convert the apngdec demuxer to pass the extradata as side data. I'll send a patch doing that. Best regards, Andreas _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
