On Mon, Mar 23, 2015 at 11:02:21PM +0000, Donny Yang wrote: > On 24 March 2015 at 01:18, Michael Niedermayer <michae...@gmx.at> wrote: > > > Either way, changes to libavcodec and libavformat should be in 2 > > seperate patches > > > Okay, I've attached the separated patches. > > > > and your code changes output to normal .png files, that is every > > whatever.png is now a apng file, iam not sure this is what the user > > expects / wants > > > I realised this might have been a problem too. > > However, I believe that when users want a normal PNG file out of ffmpeg > (i.e., individual frames), they would usually be appending `%03d` or > something similar, would that not be correct?
i think its quite a realistic use case to convert a single image like ./ffmpeg -i lena.pnm lena.png and while it may not make a big technical difference, i suspect some people would find it rather hackish if that png file was a APNG movie with a single frame > When I tested this, if the `%03d` was included, ffmpeg automatically > switched to PNG output mode, and when it was omitted, it was automatically > APNG. > > Though, would it be a good idea to add a warning to the APNG muxer that > it's running in APNG mode rather than normal PNG, and how the user can > switch back (with `-f image2`)? the code already buffers the first frame and writes it in the trailer function so by the time the frame is actually written its known if its a single frame or multi frame file and the single frame case could use syntax identical to PNG or is there some reason why a single image should be stored as APNG? a option could be added to force single images to be APNG if that has a usecase [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB What does censorship reveal? It reveals fear. -- Julian Assange
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