On 7/23/19, David Bryant <da...@wavpack.com> wrote: > On 7/21/19 11:23 PM, Paul B Mahol wrote: >> On 7/22/19, David Bryant <da...@wavpack.com> wrote: >>> Hi, >>> >>> As I promised late last year, here is a patch to add a WavPack DSD >>> decoder. >>> >>> Thanks! >>> >>> -David Bryant >>> >>> >> Please correct me if I'm wrong, but why this uses new codec id? >> Apparently is also copies some logic from other files. > > Yes, I created a new codec ID for WavPack DSD. It would be possible to just > piggyback on the existing WavPack codec by silently > decimating the DSD to PCM, but that seemed weird and wrong to me. For one > thing, the user would have no idea that the file was > actually DSD and not high sample-rate PCM. > > Also, since regular WavPack has threading enabled but WavPack DSD can't > (because of the dsd2pcm conversion) I would have to turn > off threading for all WavPack (unless there's some way of making that > conditional at runtime). It would also mean that regular > WavPack would be dependent on the dsd2pcm component even if DSD was not > required (not everyone needs DSD). And of course I was > looking closely at the only other DSD codec in FFmpeg (DST) which has its > own codec ID. > > Because regular WavPack PCM and DSD share the same block format and metadata > structure, there is a little code that is shared > between the two codecs (although they are no longer identical because of the > threading difference). Is this a problem? I could > combine the two codecs into one file and sprinkle in a few conditionals, but > I don't think it would be as clean or clear (but > might save a little duplicate code). > > That's my thinking, but obviously I am not as familiar with the FFmpeg > philosophy as you guys.
Looking carefully at dsd2pcm code in your patch, it appears it would work only with 1 or 2 channels. Is this correct? About multi-threading, as dsd2pcm can not be made multi-threaded then just do locking when doing dsd2pcm to make it single threaded and update other code as necessary. I still see no valid reason to add separate codec id. Add another wavpack profile if you wish to help users know the difference between the two. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
