CODEWITHSUNDEEP
ffmpegconfigurationfilteringvideo-processingmpv
F usedEmacs -con fused
F usedEmacs -con fused

Reputation: 11

How to make mpv more compatible with ffmpeg filters like minterpolate?

ffmpeg filter minterpolate (motion interpolation) does not work in MPV.

(Nevertheless the file then is played normally without the minterpolate).

(I researched using search engines and throughout documentation and troubleshooted to make a use of opengl and generally tried everything apart from asking for help and learning to understand more in the source code and I'm not a programmer)…

--gpu-context=angle --gpu-api=opengl also does not make opengl work. (I'm guessing opengl could help from seeing its use in the documentations).

Note

To get a full list of available video filters, see --vf=help and http://ffmpeg.org/ffmpeg-filters.html .

Also, keep in mind that most actual filters are available via the lavfi wrapper, which gives you access to most of libavfilter's filters. This includes all filters that have been ported from MPlayer to libavfilter.

Most builtin filters are deprecated in some ways, unless they're only available in mpv (such as filters which deal with mpv specifics, or which are implemented in mpv only).

If a filter is not builtin, the lavfi-bridge will be automatically tried. This bridge does not support help output, and does not verify parameters before the filter is actually used. Although the mpv syntax is rather similar to libavfilter's, it's not the same. (Which means not everything accepted by vf_lavfi's graph option will be accepted by --vf.)

You can also prefix the filter name with lavfi- to force the wrapper. This is helpful if the filter name collides with a deprecated mpv builtin filter. For example --vf=lavfi-scale=args would use libavfilter's scale filter over mpv's deprecated builtin one.

I expect MPV to play with minterpolate (one of several filters that MPV can use, listed in http://ffmpeg.org/ffmpeg-filters.html) enabled. But this is what happens:

Input: "--vf=lavfi=[minterpolate=fps=60000/1001:mi_mode=mci]"

Output:

   cplayer:  (+) Video --vid=1 (*) (h264 1280x720 29.970fps)
   cplayer:  (+) Audio --aid=1 (*) (aac 2ch 44100Hz)
        vd: Using hardware decoding (d3d11va).
    ffmpeg: Impossible to convert between the formats supported by the filter 'mpv_src_in0' and the filter 'auto_scaler_0'
     lavfi: failed to configure the filter graph
        vf: Disabling filter lavfi.00 because it has failed.

(Interesting is also that --gpu-api=opengl does not work (despite that according to specification my—not to brag—HD Graphics 400 Braswell supports its 4.2 version)… And that aresample seems to have no effect too, and with the few audio filters selected playback often doesn't start nor output errors.)

Upvotes: 1

Views: 6743

Answers (1)

Chris
Chris

Reputation: 3344

The problem is that you're using hardware decoding WITHOUT copying the decoded video back to system memory. This means your video filter can't access it. The fix is simple but that error message makes it very hard to figure this out.

To fix this just pass in --hwdec=no. Though --hwdec=auto-copy also fixes it but minterpolate in mci mode is so CPU intensive there's not much point in also using hardware decoding. (for most video sources)

All together:
mpv input.mkv --hwdec=no --vf=lavfi="[minterpolate=fps=60000/1001:mi_mode=mci]"

Explanation: The most efficient hardware decoding doesn't copy the video data back to system memory after decoding. But you need it in memory for running CPU based filtering on the decoded video data. You were asking mpv to do some video filtering but it doesn't have access to the decoded video data.

More details from the mpv docs:

auto-copy selects only modes that copy the video data back to system memory after decoding. This selects modes like vaapi-copy (and so on). If none of these work, hardware decoding is disabled. This mode is usually guaranteed to incur no additional quality loss compared to software decoding (assuming modern codecs and an error free video stream), and will allow CPU processing with video filters. This mode works with all video filters and VOs.

Because these copy the decoded video back to system RAM, they're often less efficient than the direct modes, and may not help too much over software decoding.

Upvotes: 1

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