At Wed, 11 Aug 2010 09:04:32 +0100 (BST), Mark Hills wrote: > > Hi, does anybody have any thoughts on my email below? The rate conversion > code looks stable and untouched for a while. I guess it's a missing support of 3-byte formats in 16bit conversion, so not specific to rate plugin. Adding the support shouldn't be too hard, since it's already found in 32bit conversion. thanks, Takashi > > Thanks > > On Sun, 1 Aug 2010, Mark Hills wrote: > > > I have a device (snd-usb-caiaq) whose native sample format is S24_3BE. > > When sample rate conversion is used, the audio becomes near silent, > > distorted, and only in the left channel. > > > > It is reproducable with aplay (see example below). Recording is not > > affected. Playback is correct if only format conversion is used. > > > > It looks something is causing the incorrect put function to be used by the > > rate conversion. > > > > I traced it to linear_expand() and others, alsa-lib-src/pcm_rate_linear.c. > > > > Forcing the function to put S16 format into the destination buffer allows, > > suprisingly, the sound to be heard correctly and at full volume from both > > aplay and xwax: > > > > if (rate->put_idx == 10) > > rate->put_idx = 6 > > > > I suspected that linear_init() is looking in the wrong place to choose the > > attributes for the rate conversion. After some time spent I cannot see it. > > > > But is there any reason that the output buffer for the rate conversion > > would not be in S24_3BE? And for the rate conversion to be misinformed? > > > > $ uname -s -r -v -p -i -m > > Linux 2.6.34.1-mh #83 SMP PREEMPT Wed Jul 21 23:25:33 BST 2010 i686 pentium4 i386 > > > > $ alsacap > > Card 0, ID `Audio8DJ', name `Audio 8 DJ' > > Device 0, ID `Audio 8 DJ', name `Audio 8 DJ', 4 subdevices (4 available) > > 2 channels, sampling rate 44100..96000 Hz > > Sample formats: S24_3BE > > Subdevice 0, name `subdevice #0' > > Subdevice 1, name `subdevice #1' > > Subdevice 2, name `subdevice #2' > > Subdevice 3, name `subdevice #3' > > > > $ aplay -v -D plughw:Audio8DJ,0,0 halcyon-24000.wav > > Playing WAVE 'halcyon-24000.wav' : Signed 16 bit Little Endian, Rate 24000 Hz, Stereo > > Plug PCM: Rate conversion PCM (48000, sformat=S24_3BE) > > Converter: linear-interpolation > > Protocol version: 10002 > > Its setup is: > > stream : PLAYBACK > > access : RW_INTERLEAVED > > format : S16_LE > > subformat : STD > > channels : 2 > > rate : 24000 > > exact rate : 24000 (24000/1) > > msbits : 16 > > buffer_size : 10922 > > period_size : 2730 > > period_time : 113770 > > tstamp_mode : NONE > > period_step : 1 > > avail_min : 2730 > > period_event : 0 > > start_threshold : 10922 > > stop_threshold : 10922 > > silence_threshold: 0 > > silence_size : 0 > > boundary : 715784192 > > Slave: Hardware PCM card 0 'Audio 8 DJ' device 0 subdevice 0 > > Its setup is: > > stream : PLAYBACK > > access : MMAP_INTERLEAVED > > format : S24_3BE > > subformat : STD > > channels : 2 > > rate : 48000 > > exact rate : 48000 (48000/1) > > msbits : 24 > > buffer_size : 21845 > > period_size : 5461 > > period_time : 113770 > > tstamp_mode : NONE > > period_step : 1 > > avail_min : 5461 > > period_event : 0 > > start_threshold : 21844 > > stop_threshold : 21845 > > silence_threshold: 0 > > silence_size : 0 > > boundary : 1431633920 > > appl_ptr : 0 > > hw_ptr : 0 > > > > > > -- > Mark > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
