Staxrip: LibOpus Incompatible with 5.1(side) channel layout

[pianistrevor]

Version: StaxRip 2.1.4.8 Beta

Using Opus codec with no additional parameters on a DTS-HD MA 5.1 channel audio track yields an error:

[libopus @ 0000017c89ba6880] Invalid channel layout 5.1(side) for specified mapping family -1.
Error initializing output stream 0:0 -- Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

This can be fixed by manually specifying it by saying -af "channelmap=channel_layout=5.1", but this shouldn't be necessary. I think it may be due to the recent changes committed by Patman.

[pianistrevor]

For clarification: StaxRip 2.1.4.4 Beta works with the same parameters, because it implements -ac 6 in the command line. It appears that removing the checks in commit 99dd7d0f3a857dbb2b9a607db41d810820ee06ce causes it to fail.

[GregoryL77]

This is very old ffMpeg bug with certain channels layout (eg.side). With ffMpeg default mapping family -1 , LibOpus efficiency is ~30% off. All multichannels & LFE optimizations are disabled , basically all features since Opus v1.1 are missing. https://hydrogenaud.io/index.php?topic=117698.0, https://trac.ffmpeg.org/ticket/5718 , https://trac.ffmpeg.org/ticket/5759 Workaround is using mapping family 0 or 1 while fiddling with -AC number settings, or use better encoder. Reference Opus encoder (Opus tools) CLI works like a charm . I already added this one to Staxrip as GUI encoder, will try to commit this

[pianistrevor]

Gotcha. I'll plan to use the new Opus encoder once it is committed and released.