cx88-alsa audio quality?
I forget if I've already mentioned this yet...
I recently started playing around with analog NTSC television again on my system, while trying to help someone solve a problem on their system. In the process I ran into a problem getting cx88-alsa to build with the rest of the v4l-dvb repository. As it turned out, mine was one of the stock Ubuntu kernels that have some odd issue with the I2C configuration. I had to build a vanilla kernel (2.6.26.5), making all the I2C stuff into modules as opposed to built-in. So, that's fixed - cx88-alsa builds and loads OK now.
However, I have a new problem:
Something has broken the output that cx88-alsa creates. In the case of my Kworld ATSC 120, radio output on all frequencies has a sort of growling "industrial" noise on top of the actual audio, kinda like the background noise of a manufacturing facility.
Analog TV on all channels gives clean but very tinny audio, as though the sample rate were really low (~8kHz).
Since other audio sources are working fine, I can't tell if this is a bug in the kernel, or cx88-alsa, or something else entirely. I've only noticed the problem for a matter of a week or less, so I'm not sure when it started. The problem persists as of today's pull of the v4l-dvb repository.
Signature · 8 lines
"Life is full of positive and negative events. Spend your time considering the former, not the latter." Vanessa Ezekowitz <[email protected]> -- video4linux-list mailing list Unsubscribe mailto:[email protected]?subject=unsubscribe https://www.redhat.com/mailman/listinfo/video4linux-list
Quoted 2 lines · Vanessa Ezekowitz
Analog TV on all channels gives clean but very tinny audio, as though the sample rate were really low (~8kHz).
I use a cx88 card (HVR-4000) with Analog TV (PAL). I needed to set audio to 48000Hz to get sound which is good. I use mythtv.
English is not my native language so I don't know how to describe the sound.
Anders
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i have similar problem with cx88-alsa on hvr-1300 card.
i've been using it to connect playstation2 console to my pc via a cable with both s-video and composite connectors.
while the video is in good quality, the sound sounds metallic and ofter with a very strong reverb. most of the time it's just random noise.
sometimes it seems to pick up when there is more movement in the video. when the picture gets still - the noise nearly goes away.
so far i have not found a solution to my problem (i've already asked on this mailing list for help few months ago, maybe you'll find some clues that will help you) , other than routing audio to the soundcard via additional cables, and not taking it though the capture card. changing sampling rates helps a bit.
hardware mpeg2 capture has perfect audio, however.
i suspected that my pc might be creating some sort of interference. but that doesn't explain why mpeg2 capture is unaffected by it.
oh, and i cannot find any channels on analog tv. i hope that at least radio will work (never tried it).
Quoted 10 lines · Anders Semb Hermansen
Quoted 2 lines · Vanessa Ezekowitz
Analog TV on all channels gives clean but very tinny audio, as though the sample rate were really low (~8kHz).
I use a cx88 card (HVR-4000) with Analog TV (PAL). I needed to set audio to 48000Hz to get sound which is good. I use mythtv.
English is not my native language so I don't know how to describe the sound.
Quoted 7 lines
Anders
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http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
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Quoted 4 lines · On Mon, 29 Sep 2008 01:01:51 -0500 Vanessa Ezekowitz…
I forget if I've already mentioned this yet...
I recently started playing around with analog NTSC television again on my system, while trying to help someone solve a problem on their system. In the process I ran into a problem getting cx88-alsa to build with the rest of the v4l-dvb repository. As it turned out, mine was one of the stock Ubuntu kernels that have some odd issue with the I2C configuration. I had to build a vanilla kernel (2.6.26.5), making all the I2C stuff into modules as opposed to built-in. So, that's fixed - cx88-alsa builds and loads OK now.
Quoted 8 lines
However, I have a new problem:
Something has broken the output that cx88-alsa creates. In the case of my Kworld ATSC 120, radio output on all frequencies has a sort of growling "industrial" noise on top of the actual audio, kinda like the background noise of a manufacturing facility.
Analog TV on all channels gives clean but very tinny audio, as though the sample rate were really low (~8kHz).
Since other audio sources are working fine, I can't tell if this is a bug in the kernel, or cx88-alsa, or something else entirely. I've only noticed the problem for a matter of a week or less, so I'm not sure when it started. The problem persists as of today's pull of the v4l-dvb repository.
This may be due to some issue at alsa libraries or at pulseaudio. On some tests I did with alsa, depending on the way you specify a device, you may have noise (I had lots of noise on my alsa microphone input, depending on the syntax I used to specify its input entry). You may specify it as hw: or as plughw:. The difference between them is the way libalsa will handle it, and what is specified on your alsa config files.
Cheers,
Mauro
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