Dear Tetsuya, On 2020-03-19, Tetsuya Isaki wrote: > At Tue, 10 Mar 2020 20:49:55 +0200, > Yorick Hardy wrote: > > ffmpeg4 -f oss -i /dev/audio -channels 1 -sample_rate 48000 /tmp/test.wav > > > > is completely garbled and too short. The file also seems to be 2-channel, > > so I think the recording settings are somehow not applied correctly. > > I rarely use ffmpeg4 but according to ffmpeg4 documents, > -channels/-sample_rate are for video and -ac/-ar are for audio?
If I used it correctly, it is for "-f oss" so for the input. Maybe it should go before "-i", but if I recall correctly it does not make a difference. I think "-ac" is for the output format (ffmpeg performs appropriate conversion). > % /usr/bin/time ffmpeg4 -f oss -t 0:05 -i /dev/audio -channels 1 test1.wav > 5.04 real 0.02 user 0.04 sys > % file test1.wav > test1.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, > stereo 48000 Hz > > % /usr/bin/time ffmpeg4 -f oss -t 0:05 -i /dev/audio -ac 1 test2.wav > 5.04 real 0.04 user 0.02 sys > % file test2.wav > test2.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, > mono 48000 Hz > > % /usr/bin/time audioplay test1.wav > 2.54 real 0.00 user 0.00 sys > % /usr/bin/time audioplay test2.wav > 2.54 real 0.00 user 0.00 sys > > As you said, output file was too short. However ffmpeg4 probably > recorded specified period and created small file so that I think > you need to look ffmpeg4 at first. I did not figure out why the file is too short, but there is some oss/ffmpeg interaction (maybe due to non-blocking reads?) which causes this. I created wip/ffmpeg4-nbsdaudio and nia improved it, and now recording works fine: ffmpeg4 -f nbsdaudio -i /dev/audio /tmp/netbsd.wav records as expected. > Thanks, > --- > Tetsuya Isaki <is...@pastel-flower.jp / is...@netbsd.org> Thank you! -- Kind regards, Yorick Hardy