On Sat, Jun 17, 2017 at 9:29 PM, Timo Rothenpieler <t...@rothenpieler.org> wrote: > Am 17.06.2017 um 00:11 schrieb Philip Langdale: >> >> On Fri, 16 Jun 2017 21:53:22 +0200 >> wm4 <nfx...@googlemail.com> wrote: >> >>> On Fri, 16 Jun 2017 20:31:14 +0200 >>> Timo Rothenpieler <t...@rothenpieler.org> wrote: >>> >>>> Am 16.06.2017 um 16:41 schrieb Philip Langdale: >>>>> >>>>> This is mechanically simple, but does the fact that additional >>>>> command line arguments have to be used to get the same results >>>>> count as a compatibility break? Do we need to fix that before we >>>>> can actually make this change? >>>> >>>> >>>> I'd consider that as a breaking change, even though things don't >>>> "break", it results in unexpected behavior that is not obvious. >>> >>> >>> Probably, but it's also slightly saner in general if you consider that >>> a user could add video filters. Currently, hwaccel filters and normal >>> filters are completely different beasts, so the user needs to be aware >>> of the difference, and select the appropriate mode. So depending on >>> whether you output hw surfaces by default, you'll break hw filters or >>> sw filters by default. Making sure sw filters work by default seems >>> like the better choice. >>> >>> But yes, maybe we could rename the hwaccel just so that users of the >>> old hwaccel become aware of the change. You could even keep the old >>> hwaccel name, and make it somehow override the -hwaccel_output_format >>> option and print a warning, in case you care enough for compatibility >>> in this case. >> >> >> We could use it as an opportunity to rename it to 'cuda' which is more >> accurate. >> >> Keeping the old specialised code for 'cuvid' would also ensure >> compatibility :-) > > > One thing to keep in mind is that cuvid is vastly different from other > hwaccels. > While for example for vaapi, specifying -hwaccel vaapi makes the h264 > decoder use vaapi. But for cuvid, the h264_cuvid decoder always uses > hardware, and the -hwaccel cuvid flag is essentially used to switch its > output mode to cuda frames. > With the new approach, there is no apparent difference from using cuvid with > or without -hwaccel cuvid. > That situation would seem kinda weird and confusing to me. >
The situation right now is weird and confusing, specifically because -hwaccel cuvid is different from all the others. To rectify that, it should probably be changed to behave just like -hwaccel vaapi or similar So basically, -hwaccel cuvid should instruct ffmpeg.c to use the cuvid-based decoders, without needing to manually specify them on top of that, and thats all it should do - ie. it behaves just like -hwaccel vaapi/dxva2, just with a different logic in the background. - Hendrik _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel