>On Wed, Sep 15, 2021 at 10:36:23PM -0700, Sean Greenslade wrote: >> On Wed, Sep 15, 2021 at 09:59:00PM +0530, Vijendar Reddy Mukunda wrote: >> > Hello, >> > >> > I was just experimenting with a null sink. >> > I have created null sink with 48000Hz sample rate, s16le, channels as 6. >> > Tried to record from null sink monitor source. >> > But when i run parecord command, I am seeing the below error. >> > Warning: failed to write channel map to file. >> > I have also tried null sink creation >> > with channel_map=front-left,front-right,rear-left,rear-right,front-center,lfe. >> > But no luck. >> > Need inputs on fixing this channel map issue. >> >> That error is just a warning, and can most likely be ignored. Not all >> sound formats actually support writing the channel map into them. In >> fact, according to the libsndfile docs, only AIFF and CAF are supported: >> >> https://libsndfile.github.io/libsndfile/command.html#sfc_set_channel_map_info >> >> What file format are you using? > > Thank you for your explanation. > We are trying to play youtube content. > One more question on the same line. > we have created a null sink with 192khz/8ch/s32le and channel map as > "front-left,front-right,rear-left,rear-right,front-center,lfe,side-left,side-right" > When we record null sink monitor output, we are seeing complete silence > in one channel. > As we are using lfe as one channel, do we need to do any extra settings > on lfe channel? Well, does your source media have 7.1 channel audio? If not, you'll need to turn on the "remixing-produce-lfe" setting in daemon.conf. If it does, then you'll need to dig deeper into what exactly your playback software is doing. --Sean
