[MPlayer-dev-eng] [FFmpeg-devel] [PATCH 0/20] removal of deprecated features

[compn]

I am forwarding this mail to mplayer-dev-eng list in the hopes that
maybe someone would like to work on updating mplayer to the new ff* api.

thanks to reimar for updating some api already and rtogni for posting a
patch and also wm4 for suggesting checking patches from mplayer2 to
avoid duplicating work.

-compn


On Wed, 5 Aug 2015 21:31:38 +0200
Andreas Cadhalpun <andreas.cadhalpun at googlemail.com> wrote:

> On 04.08.2015 07:57, Reimar Döffinger wrote:
> > I do have on more proposal, but the problem is it needs someone to
> > do the work. For each removed feature, prepare documentation "a
> > monkey could follow" on how to replace it (you could call it a
> > transition guide). Even better, a script that automates it where
> > reasonable.
> 
> I think this is a very good idea.
> 
> > In some cases it is just a matter of copy-pasting some existing
> > wrapper code, particularly if we remove that wrapper code it is
> > useful if people still have it available in the new release.
> > If it's just a few hours of someone's time who even doesn't need to
> > understand the code, I think we can very confidently say "not
> > really our problem" if some applications still use it.
> 
> Agreed.
> 
> > If we that way find out that there are non-trivial cases or cases
> > where the code gets a lot more complicated it might be a hint the
> > new API is still crap and we maybe should come up with something
> > better first.
> 
> A more complete usage list for the deprecated APIs is:
> 
> FF_API_PIX_FMT: 71
> amide avbin avifile bino blender chromium-browser dff dolphin-emu
> dvbcut dvswitch ffdiaporama ffmpeg2theora ffmpegthumbnailer
> ffmpegthumbs ffms2 fuse-emulator-utils gazebo gmerlin-avdecoder
> gmerlin-encoders gnash gpac gst-libav1.0 guvcview harvid hedgewars
> info-beamer jugglemaster karlyriceditor kino kodi lightspark lebiniou
> libam7xxx libavg libde265 libextractor libquicktime linphone lives
> lynkeos.app mlt mplayer mplayer2 mrpt opal opencv openmw
> openscenegraph ovito paraview performous pjproject qutecom rbdoom3bfg
> renpy shotdetect sflphone strigi survex transcode vcmi vlc vtk vtk6
> vxl wxsvg x264 xjadeo xpra yorick-av zoneminder
> 
> FF_API_AVFRAME_LAVC: 53
> alsa-plugins amarok aubio avbin blender chromaprint dff dolphin-emu
> dvbcut ffdiaporama ffmpegthumbnailer ffmpegthumbs fuse-emulator-utils
> gazebo gmerlin-avdecoder gmerlin-encoders goldendict gpac
> gst-libav1.0 hedgewars info-beamer jugglemaster kino libavg
> libextractor libquicktime lightspark linphone mplayer mplayer2 mrpt
> opal opencv openscenegraph ovito paraview performous pianopar qutecom
> renpy shotdetect spek squeezelite transcode vcmi vlc vtk vtk6 vxl
> xine-lib-1.2 xpra yorick-av zoneminder
> 
> FF_API_GET_BUFFER: 9
> avifile dvswitch gmerlin-avdecoder gst-libav1.0 libavg mplayer
> mplayer2 openmw openscenegraph
> 
> FF_API_AUDIOCONVERT: 7
> alsa-plugins cantata ffdiaporama moc mplayer2 mpv vlc
> 
> FF_API_SWS_CPU_CAPS: 6
> fuse-emulator-utils kodi mlt mplayer2 vlc zoneminder
> 
> FF_API_DEINTERLACE: 5
> blender dff ffmpegthumbnailer ffmpegthumbs vxl
> 
> FF_API_AVFRAME_LAVC(qscale): 3
> ffmpeg2theora kodi xine-lib-1.2
> 
> FF_API_CODEC_ID: 3
> chromium-browser dvswitch ffms2
> 
> FF_API_CONTEXT_SIZE: 3
> mplayer mplayer2 xine-lib-1.2
> 
> FF_API_REQUEST_CHANNELS: 3
> mplayer mplayer2 renpy
> 
> FF_API_AV_REVERSE: 2
> mplayer mplayer2
> 
> FF_API_AVCODEC_RESAMPLE: 2
> mlt mplayer
> 
> FF_API_DESTRUCT_PACKET: 2
> lives openmw
> 
> FF_API_AVFILTERBUFFER: 2
> ffdiaporama pianobar
> 
> FF_API_AVFILTERPAD_PUBLIC: 1
> mplayer
> 
> FF_API_VIMA_DECODER: 1
> mplayer
> 
> 
> 
> FF_API_PIX_FMT and FF_API_AVFRAME_LAVC are still widely used, but the
> "patch-monkey" could deal with the changes and also with
> FF_API_AUDIOCONVERT, FF_API_SWS_CPU_CAPS, FF_API_CODEC_ID,
> FF_API_CONTEXT_SIZE, FF_API_REQUEST_CHANNELS and FF_API_VIMA_DECODER.
> 
> Regarding FF_API_GET_BUFFER, get_buffer should be replaced with
> get_buffer2, but it's not clear how release_buffer/reget_buffer
> should be replaced. Can someone explain/document this?
> 
> To get rid of FF_API_DEINTERLACE, one should 'use yadif (in
> libavfilter) instead'. Well, ... how?
> 
> Then, as part of FF_API_AVFRAME_LAVC(qscale), the fields
> qscale_table, qstride and qscale_type of AVFrame are to be removed,
> but (at least in FFmpeg) these are used by the not deprecated
> functions av_frame_set_qp_table and av_frame_get_qp_table, so they
> shouldn't be removed. Anyway it's not clear how to replace their
> usage. 
> 
> Why is FF_API_AV_REVERSE deprecated?
> It is used in FFmpeg's libavutil/eval.c.
> 
> One should 'use libswresample instead' of FF_API_AVCODEC_RESAMPLE.
> A more detailed explanation would be good.
> 
> Same holds for FF_API_DESTRUCT_PACKET, where one should 'use the
> AVBuffer API instead'.
> 
> For FF_API_AVFILTERBUFFER no replacement is documented.
> 
> FF_API_AVFILTERPAD_PUBLIC should be replaced by avfilter_pad_get_name
> and avfilter_pad_get_type, but it seems that mplayer also uses others.
> 
> Better documentation would surely be helpful.
> 
> > Btw. the magic option to enable compatibility is still somewhat
> > useful as it lists and allows testing the specific changes that are
> > coming up. But I agree it's only a minor help.
> 
> The problem with such a magic option is that it combines the
> disadvantages of removing and not removing: Programs using the old
> API get broken by default and the deprecated functionality remains in
> the code base.
> 
> Best regards,
> Andreas