Remap AC3 channels losslessly?

[alleycat]

Just checking if anyone knows of a way to remap the channels of an AC3 file without encoding? Is it possible to do this losslessly? Or do I need to convert to wav, remap and then encode as DTS HD or 640 kbps AC3 etc? Thanks

[stwd4nder2]

You could try this:
https://ffmpeg.org/ffmpeg-filters.html#channelmap
If you use it with the '-c copy' flag then it shouldn't re-encode the audio. I'm not sure if this will affect the dialnorm value or not though.

[alleycat]

You could try this:
https://ffmpeg.org/ffmpeg-filters.html#channelmap
If you use it with the '-c copy' flag then it shouldn't re-encode the audio. I'm not sure if this will affect the dialnorm value or not though.

Thanks. Well it's worked, but unfortunately lossless didn’t work.

"Filtering and streamcopy cannot be used together"