2018-12-04 16:58 GMT+01:00, Eric Jong <[email protected]>: >> Did you test without the line? > > Yes, I did a test without the line for libav 4.0.3 and just now with the > latest > snapshot, with and without the line. > I did not find a good explanation how interlaced content is encoded with > mpeg-2, > but from the source I can make the following observations: > > Interlaced content consist of an odd field and an even field and these are > stored > as seperate frames in the mpeg-stream. The decoder decodes both fields and > merges > them directly in the resulting frame. This saves us an extra image > processing step > if we would output this frame to an display immediatly. (beside the point, > we don't, > we would need to deinterlace these frames first or output it to an encoder > card as > interlaced content) > > As the original source contained captions, these were added to the fields in > the > mpeg stream. As these two fields are merged into a single AVFrame we also > get two > sidedata packets of AV_FRAME_DATA_A53_CC. And we need both! > > With the line av_frame_remove_side_data: sidedata AV_FRAME_DATA_A53_CC of > first field > is discarded. > Without the line: Each AVFrame contains AV_FRAME_DATA_A53_CC twice. > > Please add the patch without av_frame_remove_side_data. And do not consider > of merging > the AV_FRAME_DATA_A53_CC sidedata, as this will make analysing these closed > captions > more difficult (then which data belonged to which frame)
Interesting, how did you test? I ask because I don't get anything useful if I don't discard the first field's data. Carl Eugen _______________________________________________ Libav-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/libav-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
