Trouble grabbing from TV capture device

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Trouble grabbing from TV capture device

Simon
I have a little device that takes "old" composite video and sends it out to
USB. It's recognized by video4linux2 and I can watch the VHS tapes that I'm
trying to capture using xawtv simply using:

v4lctl -c /dev/video2 setnorm NTSC
v4lctl -c /dev/video2 movie fps 29.97
and then "xawtv"

When I start xawtv it says it's getting audio from hw:3,0

I can also play the video, but *without*sound* using:

ffplay -f v4l2 -i /dev/video2 -vf yadif

and the picture is just great (well, for a home movie on VHS tape, at
least!) but I get no sounds from this.

I have tried capturing in a variety of formats, but always end up with a
silent sound-track (if I don't specify explicitly that I want -f alsa and
some audio source, I don't even get a sound track). Anway, there seems
little point in dumping the output of half a dozen failures, This one I
think is representative: If I try to do ffplay directly on the audio using:

ffplay -f alsa -i plughw:3,0

I get a black window (not surprising, I didn't specify a video source!),
silence, and the following output that runs for as long as I let it until I
kill it with control-c.

$ ffplay -f alsa -i plughw:3,0
ffplay version 4.2.4-1ubuntu0.1 Copyright (c) 2003-2020 the FFmpeg
developers
  built with gcc 9 (Ubuntu 9.3.0-10ubuntu2)
  configuration: --prefix=/usr --extra-version=1ubuntu0.1
--toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu
--incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl
--disable-stripping --enable-avresample --disable-filter=resample
--enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom
--enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca
--enable-libcdio --enable-libcodec2 --enable-libflite
--enable-libfontconfig --enable-libfreetype --enable-libfribidi
--enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame
--enable-libmysofa --enable-libopenjpeg --enable-libopenmpt
--enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband
--enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex
--enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab
--enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp
--enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq
--enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl
--enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm
--enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r
--enable-libx264 --enable-shared
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
Input #0, alsa, from 'plughw:3,0': 0KB vq=    0KB sq=    0B f=0/0
  Duration: N/A, start: 1598560765.378207, bitrate: 1536 kb/s
    Stream #0:0: Audio: pcm_s16le, 48000 Hz, 2 channels, s16, 1536 kb/s
1598560779.36 M-A:  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0

it seems to think there's "something there" (it doesn't reject "plughw:3,0"
as bogus) and to have detected something with a format, yet, nothing.

Any idea how to proceed? Can I get more information from xawtv perhaps that
might help me know how it's succeeding and transfer that info to ffmpeg?

TIA,
Simon


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Simon Roberts
(303) 249 3613
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Re: Trouble grabbing from TV capture device

Carl Zwanzig
On 8/27/2020 1:52 PM, Simon Roberts wrote:
> I have a little device that takes "old" composite video and sends it out to
> USB. It's recognized by video4linux2 and I can watch the VHS tapes that I'm
> trying to capture using xawtv simply using:
>
> v4lctl -c /dev/video2 setnorm NTSC
> v4lctl -c /dev/video2 movie fps 29.97
> and then "xawtv"
>
> When I start xawtv it says it's getting audio from hw:3,0

Do you have a sound connection from the vcr to this device? Does it actually
have good audio on it? Tried another source? (composite video does not have
embedded audio)

z!
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Re: Trouble grabbing from TV capture device

Peter van den Houten
In reply to this post by Simon
On 27/08/2020 22:52, Simon Roberts wrote:

> I have a little device that takes "old" composite video and sends it out to
> USB. It's recognized by video4linux2 and I can watch the VHS tapes that I'm
> trying to capture using xawtv simply using:
>
> v4lctl -c /dev/video2 setnorm NTSC
> v4lctl -c /dev/video2 movie fps 29.97
> and then "xawtv"
>
> When I start xawtv it says it's getting audio from hw:3,0
>
> I can also play the video, but *without*sound* using:
>
> ffplay -f v4l2 -i /dev/video2 -vf yadif
>
> and the picture is just great (well, for a home movie on VHS tape, at
> least!) but I get no sounds from this.
>
> I have tried capturing in a variety of formats, but always end up with a
> silent sound-track (if I don't specify explicitly that I want -f alsa and
> some audio source, I don't even get a sound track). Anway, there seems
> little point in dumping the output of half a dozen failures, This one I
> think is representative: If I try to do ffplay directly on the audio using:
>
> ffplay -f alsa -i plughw:3,0
>
> I get a black window (not surprising, I didn't specify a video source!),
> silence, and the following output that runs for as long as I let it until I
> kill it with control-c.
>
> $ ffplay -f alsa -i plughw:3,0
> ffplay version 4.2.4-1ubuntu0.1 Copyright (c) 2003-2020 the FFmpeg
> developers
>   built with gcc 9 (Ubuntu 9.3.0-10ubuntu2)
>   configuration: --prefix=/usr --extra-version=1ubuntu0.1
> --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu
> --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl
> --disable-stripping --enable-avresample --disable-filter=resample
> --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom
> --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca
> --enable-libcdio --enable-libcodec2 --enable-libflite
> --enable-libfontconfig --enable-libfreetype --enable-libfribidi
> --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame
> --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt
> --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband
> --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex
> --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab
> --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp
> --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq
> --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl
> --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm
> --enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r
> --enable-libx264 --enable-shared
>   libavutil      56. 31.100 / 56. 31.100
>   libavcodec     58. 54.100 / 58. 54.100
>   libavformat    58. 29.100 / 58. 29.100
>   libavdevice    58.  8.100 / 58.  8.100
>   libavfilter     7. 57.100 /  7. 57.100
>   libavresample   4.  0.  0 /  4.  0.  0
>   libswscale      5.  5.100 /  5.  5.100
>   libswresample   3.  5.100 /  3.  5.100
>   libpostproc    55.  5.100 / 55.  5.100
> Input #0, alsa, from 'plughw:3,0': 0KB vq=    0KB sq=    0B f=0/0
>   Duration: N/A, start: 1598560765.378207, bitrate: 1536 kb/s
>     Stream #0:0: Audio: pcm_s16le, 48000 Hz, 2 channels, s16, 1536 kb/s
> 1598560779.36 M-A:  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0
>
> it seems to think there's "something there" (it doesn't reject "plughw:3,0"
> as bogus) and to have detected something with a format, yet, nothing.
>
> Any idea how to proceed? Can I get more information from xawtv perhaps that
> might help me know how it's succeeding and transfer that info to ffmpeg?
>
> TIA,
> Simon
>
>
Try using the line/mic input on the computer, not the audio cable to the USB device.

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PvdH
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Re: Trouble grabbing from TV capture device

Simon
In reply to this post by Simon
I was unclear:

On Thu, Aug 27, 2020 at 2:52 PM Simon Roberts <
[hidden email]> wrote:

> I have a little device that takes "old" composite video and sends it out
> to USB. It's recognized by video4linux2 and I can watch the VHS tapes that
> I'm trying to capture using xawtv simply using:
>
> v4lctl -c /dev/video2 setnorm NTSC
> v4lctl -c /dev/video2 movie fps 29.97
> and then "xawtv"
>
> When I start xawtv it says it's getting audio from hw:3,0
>
> When I said above "I can watch" I meant "xawtv works completely, with both
sound and video"
However, as outlined below, none of the other attempts I've made seem to be
able to get at that sound.
So, yes, the audio hardware is demonstrably working fine "end to end".

One kind commenter noted that I could grab sound from another source.
That's true, and does work, but it's way out of sync, so if I can make this
work all on the one piece of hardware, that would be preferable.


> I can also play the video, but *without*sound* using:
>
> ffplay -f v4l2 -i /dev/video2 -vf yadif
>
> and the picture is just great (well, for a home movie on VHS tape, at
> least!) but I get no sounds from this.
>
> I have tried capturing in a variety of formats, but always end up with a
> silent sound-track (if I don't specify explicitly that I want -f alsa and
> some audio source, I don't even get a sound track). Anway, there seems
> little point in dumping the output of half a dozen failures, This one I
> think is representative: If I try to do ffplay directly on the audio using:
>
> ffplay -f alsa -i plughw:3,0
>
> I get a black window (not surprising, I didn't specify a video source!),
> silence, and the following output that runs for as long as I let it until I
> kill it with control-c.
>
> $ ffplay -f alsa -i plughw:3,0
> ffplay version 4.2.4-1ubuntu0.1 Copyright (c) 2003-2020 the FFmpeg
> developers
>   built with gcc 9 (Ubuntu 9.3.0-10ubuntu2)
>   configuration: --prefix=/usr --extra-version=1ubuntu0.1
> --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu
> --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl
> --disable-stripping --enable-avresample --disable-filter=resample
> --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom
> --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca
> --enable-libcdio --enable-libcodec2 --enable-libflite
> --enable-libfontconfig --enable-libfreetype --enable-libfribidi
> --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame
> --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt
> --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband
> --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex
> --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab
> --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp
> --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq
> --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl
> --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm
> --enable-libiec61883 --enable-nvenc --enable-chromaprint --enable-frei0r
> --enable-libx264 --enable-shared
>   libavutil      56. 31.100 / 56. 31.100
>   libavcodec     58. 54.100 / 58. 54.100
>   libavformat    58. 29.100 / 58. 29.100
>   libavdevice    58.  8.100 / 58.  8.100
>   libavfilter     7. 57.100 /  7. 57.100
>   libavresample   4.  0.  0 /  4.  0.  0
>   libswscale      5.  5.100 /  5.  5.100
>   libswresample   3.  5.100 /  3.  5.100
>   libpostproc    55.  5.100 / 55.  5.100
> Input #0, alsa, from 'plughw:3,0': 0KB vq=    0KB sq=    0B f=0/0
>   Duration: N/A, start: 1598560765.378207, bitrate: 1536 kb/s
>     Stream #0:0: Audio: pcm_s16le, 48000 Hz, 2 channels, s16, 1536 kb/s
> 1598560779.36 M-A:  0.000 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0
>
> it seems to think there's "something there" (it doesn't reject
> "plughw:3,0" as bogus) and to have detected something with a format, yet,
> nothing.
>
> Any idea how to proceed? Can I get more information from xawtv perhaps
> that might help me know how it's succeeding and transfer that info to
> ffmpeg?
>
>
>
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