MPV's interpolation not working when passthrough audio directly to A/V receiver.

[aaaatheone]

MPV version: 0.36.0-623-g6e428c26-20231022 Windows: Windows 11 build 10.0.22621.2428 libplacebo version: v6.338.0-40 FFmpeg version: N-112499-ga76b409dd

Today I have found MPV's interpolation system just getting disabled automatically when passthrough(bitstreaming) audio directly to A/V receiver via HDMI.I think that is the only command audio-spdif=ac3,dts,dts-hd,eac3,truehd which is killing or disabling MPV's own build interpolation mechanism during playback of 24fps videos. bellow is screenshot when not using passthrough rather then directly with windows PCM audio or PCM output to A/V receiver.In this both cases interpolation working fine. See the green arrow section, it indicating mpv's interpolation working properly when outputting in PCM( see the yellow arrow section) audio to any devices. BUT When bitstreaming, the interpolation method just disabled automatically(see the read arrow section) and I don't know how to enable it. What more extra commands I have to put in mpv.conf file in order to play with interpolation when audio passthrough?and another additional question, why audio Sample Rate always shows 192000hz where audio source is 48000hz when bitstreaming?

[eXmendiC]

For interpolation you usually use "video-sync=display-resample", take a look at the docs: https://mpv.io/manual/master/#options-video-sync "Resample audio to match the video. This mode will also try to adjust audio speed to compensate for other drift." Passthrough makes it impossible to adjust the audio, because it's sent untouched. You could try it with another "display-" method that doesn't need audio adjusting, but that might come with huge disadvantages not worth it. There is usually no reason to passthrough audio in the first place, except PCM conversion can't handle it - which is the case for Dolby Atmos or DTS:X, see: https://github.com/mpv-player/mpv/issues/12703

[aaaatheone]

@eXmendiC thank you for pointed out which command have to put for resolve this issue, I have chosen display-tempo and let see any audio sync issue happen or not.Bitscreaming is impotent to me because I want to play my Home theater as pro by not touching Audio output by any conversion rather then directly to AV device. I had another question about why always 192000hz audio sample rate when passthrough to external device when audio source is 48000hz.any logic behind it?

[eXmendiC]

PCM or untouched shouldn't really make a difference with a decent audio setup, lossless is lossless. Anyway, about the 192000hz: https://github.com/mpv-player/mpv/issues/6419

[aaaatheone]

ok got the 192000hz answer. thanks