Hi Carl, Thanks for getting back to me so quick.
On Wed, Jul 13, 2016 at 9:37 AM, Carl Eugen Hoyos <[email protected]> wrote: > Kieran O Leary <kieran.o.leary <at> gmail.com> writes: > >> A .mov source with no SAR/DAR information (listed as #sar 0: 0/1) >> in the framemd5, has specific SAR information when remuxed as mkv >> (#sar 0: 1/1). Obviously these values are also available via >> ffmpeg -i input. > > Not really: > The muxer does not write a value if sar == 0/1 (the field is not > mandatory) but the demuxer always provides a value to the world. > You could read the mkv specification in a way that this is > correct (because a sar of 1/1 is the default for mkv). > > Does the demuxing behaviour hit you? It only means that I have to come up with a different way (ignore the commented lines in framemd5 output) of diffing input/output framemd5 files when transcoding, which I should be doing anyway. > It could be changed but this is isn't completely trivial: > For 3D files, the SAR is 2/1 (or 1/2) by default, so in this > case, the demuxer would still have to output a sar although > not specified in the file. I understand. I don't know how essential it is, seeing as no SAR would mean 1:1 anyhow. The only case that I can think of is if an archivist was really desperate to preserve as many properties of the original file when remuxing to another container. Seeing as PAR/SAR is a significant property of the source, its declaration, or non-declaration possibly should be preserved, even if players will treat the file the same way regardless. I can probably live without it as I'd prefer if the SAR was declared in the source to begin with. > > Carl Eugen > Best, Kieran. _______________________________________________ ffmpeg-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
