Hi all, I have been developing alsa driver for wm8974 + i.MX27.By now, the playback channel works well. But there is lots of noise in my record file. The input audio is from aux input. I have configured wm8974 so that ONLY the aux input goes into ADC. (The INPPGAMUTE bit is 1 and the MICP2BOOSTVOL is 0.) And I have enabled the Speaker Line Bypass switch so that I can verify that the aux input is correct and the bypass output is very clear. That means that there is nothing wrong with the ADC input. But the wav file (generated by command "arecord -d 20 -c 1 -f S16_LE -r 8000 -t wav foobar.wav") contains both the aux input audio and lots of noise, which makes the quality of the record file even unacceptable. Since the playback works well, the register setting of wm8974 and mx27 ssi seems to be correct. What's the possible reason causing so much noise? Can the digital filers of ADC be helpful to eliminate recording noise and improve the quality of record file? Regards, Jie _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
