Em 06-09-2011 23:58, Devin Heitmueller escreveu: > On Tue, Sep 6, 2011 at 11:29 AM, Mauro Carvalho Chehab > <mchehab@xxxxxxxxxx> wrote: >> There are several issues with the original alsa_stream code that >> got fixed on xawtv3, made by me and by Hans de Goede. Basically, >> the code were re-written, in order to follow the alsa best >> practises. >> >> Backport the changes from xawtv, in order to make it to work on a >> wider range of V4L and sound adapters. >> >> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx> > > Mauro, > > What tuners did you test this patch with? I tested with some em28xx-based devices, like HVR-950 and WinTV USB2. > I went ahead and did a git pull of your patch series into my local > git tree, and now my DVC-90 (an em28xx device) is capturing at 32 KHz > instead of 48 (this is one of the snd-usb-audio based devices, not > em28xx-alsa). The new approach tries to match an speed that it is compatible between the audio and the video card. The algorithm tries first to not use software interpolation for audio, as it would reduce the audio quality. If it can't do it without interpolation, it will enable interpolation and seek again. By default, pulseaudio does interpolation, if you request it to use a different resolution. > Note I tested immediately before pulling your patch series and the > audio capture was working fine. Had you test to disable pulseaudio and see what speeds your boards accept? If you enable verbose mode, you'll see more details about the device detection. For example, this is what I get here with hvr-950, calling "tvtime -v": alsa: starting copying alsa stream from hw:1,0 to hw:0,0 videoinput: Using video4linux2 driver 'em28xx', card 'Hauppauge WinTV HVR 950' (bus usb-0000:00:1d.7-1). videoinput: Version is 196608, capabilities 5030051. alsa: Capture min rate is 48000 alsa: Capture max rate is 48000 alsa: Playback min rate is 44100 alsa: Playback max rate is 192000 alsa: Will search a common rate between 48000 and 48000 alsa: Using Rate 48000 alsa: capture periods range between 2 and 98. Want: 2 alsa: capture period time range between 333 and 65334. Want: 15000 alsa: playback periods range between 2 and 32. Want: 4 alsa: playback period time range between 666 and 10922667. Want: 15000 alsa: capture period set to 2 periods of 15000 time alsa: playback period set to 4 periods of 15333 time alsa: Negociated configuration: stream : PLAYBACK access : RW_INTERLEAVED format : S16_LE subformat : STD channels : 2 rate : 48000 exact rate : 48000 (48000/1) msbits : 16 buffer_size : 2944 period_size : 736 period_time : 15333 tstamp_mode : NONE period_step : 1 avail_min : 736 period_event : 0 start_threshold : 1440 stop_threshold : 2944 silence_threshold: 0 silence_size : 0 boundary : 1543503872 stream : CAPTURE access : RW_INTERLEAVED format : S16_LE subformat : STD channels : 2 rate : 48000 exact rate : 48000 (48000/1) msbits : 16 buffer_size : 1440 period_size : 720 period_time : 15000 tstamp_mode : NONE period_step : 1 avail_min : 720 period_event : 0 start_threshold : 720 stop_threshold : 1440 silence_threshold: 0 silence_size : 0 boundary : 1509949440 alsa: Parameters are 48000Hz, S16_LE, 2 channels alsa: Set bitrate to 48000, buffer size is 1440 alsa: stream started from hw:1,0 to hw:0,0 (48000 Hz, buffer delay = 30,00 ms) And those are the results with WinTV USB2: videoinput: Using video4linux2 driver 'em28xx', card 'Hauppauge WinTV USB 2' (bus usb-0000:00:1d.7-1). videoinput: Version is 196608, capabilities 5030041. alsa: starting copying alsa stream from hw:1,0 to hw:0,0 alsa: Capture min rate is 32000 alsa: Capture max rate is 32000 alsa: Playback min rate is 44100 alsa: Playback max rate is 192000 alsa: Will search a common rate between 44100 and 32000 alsa: Couldn't find a rate that it is supported by both playback and capture alsa: Trying plughw:0,0 for playback alsa: Resample enabled. alsa: Capture min rate is 32000 alsa: Capture max rate is 32000 alsa: Playback min rate is 4000 alsa: Playback max rate is 4294967295 alsa: Will search a common rate between 32000 and 32000 alsa: Using Rate 32000 alsa: capture periods range between 2 and 1024. Want: 2 alsa: capture period time range between 500 and 4096000. Want: 15000 alsa: playback period time range between 333 and 5461334. Want: 15000 alsa: capture period set to 2 periods of 15000 time alsa: playback period set to 4 periods of 15000 time alsa: Negociated configuration: stream : PLAYBACK access : RW_INTERLEAVED format : S16_LE subformat : STD channels : 2 rate : 32000 exact rate : 32000 (32000/1) msbits : 16 buffer_size : 1920 period_size : 480 period_time : 15000 tstamp_mode : NONE period_step : 1 avail_min : 480 period_event : 0 start_threshold : 960 stop_threshold : 1920 silence_threshold: 0 silence_size : 0 boundary : 503316480 stream : CAPTURE access : RW_INTERLEAVED format : S16_LE subformat : STD channels : 2 rate : 32000 exact rate : 32000 (32000/1) msbits : 16 buffer_size : 960 period_size : 480 period_time : 15000 tstamp_mode : NONE period_step : 1 avail_min : 480 period_event : 0 start_threshold : 480 stop_threshold : 960 silence_threshold: 0 silence_size : 0 boundary : 2013265920 alsa: Parameters are 32000Hz, S16_LE, 2 channels alsa: Set bitrate to 32000 with resample enabled at playback, buffer size is 960 alsa: stream started from hw:1,0 to plughw:0,0 (32000 Hz, buffer delay = 30,00 ms) You should notice that snd-usb-audio only reports 32 kHz speed for this device. > I think this patch series is going in the right direction in > general, but this patch in particular seems to cause a regression. > Is this something you want to investigate? I think we need to hold > off on pulling this series into the new tvtime master until this > problem is resolved. > > Devin > / -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
