Hi I'm probably using ffmpeg in an edge-case way, but I simply want to take 2 channels/stereo, and end up with 6 channels of audio, where I can apply/modify/filter each channel as I please. And I figured out the ffmpeg magic to do this, but along my dive into this it appears that no matter the method used to upmix (of which there are many such as "-ac 6", "asplit", "pan", "channelsplit") it appears no matter what, I'm forced to use the upmixing scheme that always sets channel 4 to a lowpass filter of 128hz, rendering it useless for my case.
There doesn't appear to be a way to disable this that I can find, and it seems like there should be My current command I'm using, which works great except for channel 4 (labeled r2 in here). No matter what filter I apply, it always ends up being a lowpass of 128. -err_detect ignore_err -filter_complex [0:a]channelsplit[left][right];[left]asplit=3[l1][l2][l3];[l1]aecho=1.0:0.7:25|60:0.5|0.3[l1];[l2]lowpass=f=550[l2];[l3]adelay=1,aecho=1.0:0.7:25|60:0.5|0.3[l3];[right]asplit=3[r1][r2][r3];[r1]aecho=1.0:0.7:25|60:0.5|0.3[r1];[r2]lowpass=f=550[r2];[r3]adelay=1,aecho=1.0:0.7:25|60:0.5|0.3[r3];[l1][r1][l2][r2][l3][r3]amerge=inputs=6[a] -map 0:v -map [a] -acodec aac -c:v copy The code, at a glance, seems to corroborate this, but it's a bit beyond my depth to do anything further (and I don't want to compile / make a custom version of ffmpeg) https://github.com/FFmpeg/FFmpeg/blob/9aa20d28cdda0dcaa4daa2848670a6530c6ba26a/libavfilter/af_surround.c So, if possible, how can I disabled the upmixing scheme? Thanks! -- Sincerely, Jeremy _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
