Mailing List Archive

PVR-500 frame size
I've been using my PVR-500 with analog (composite) NTSC input for some
years vlc. I had been using the "vlc pvr:///dev/video0" which worked,
but recently vlc has dropped the pvr interface in favor of v4lc.
Unfortunately, it means my external video can no longer be displayed.
Searching for answers, I came across this bug report:
https://trac.videolan.org/vlc/ticket/10258 which describes my symptoms
exactly, but was closed as "not a vlc bug."

I'm a competent programmer and would be willing to help fix this, but
wanted some help in understanding what exactly needs fixing, so I've
come here. I *think* I'm in the right place for that, but if not, a
gentle suggestion for redirection to some other list would be helpful.

Ed

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Re: PVR-500 frame size [ In reply to ]
----- Original Message -----
> From: "Ed Beroset" <beroset@mindspring.com>

> I'm a competent programmer and would be willing to help fix this, but
> wanted some help in understanding what exactly needs fixing, so I've
> come here. I *think* I'm in the right place for that, but if not, a
> gentle suggestion for redirection to some other list would be helpful.

Just for giggles: have you pointed mplayer2 at it? What does it say?

Cheers,
-- jra
--
Jay R. Ashworth Baylink jra@baylink.com
Designer The Things I Think RFC 2100
Ashworth & Associates http://baylink.pitas.com 2000 Land Rover DII
St Petersburg FL USA #natog +1 727 647 1274

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Re: PVR-500 frame size [ In reply to ]
Jay Ashworth wrote:
> ----- Original Message -----
>> From: "Ed Beroset" <beroset@mindspring.com>
>
>> I'm a competent programmer and would be willing to help fix this, but
>> wanted some help in understanding what exactly needs fixing, so I've
>> come here. I *think* I'm in the right place for that, but if not, a
>> gentle suggestion for redirection to some other list would be helpful.
>
> Just for giggles: have you pointed mplayer2 at it? What does it say?

Good question. In fact, mplayer displays just fine, as does "cat
/dev/video0 > test.mpg" followed by playing the resulting video in vlc.
Here's what mplayer says:

mplayer: could not connect to socket
mplayer: No suc
Playing /dev/video0.
libavformat version 55.19.104 (external)
Cannot seek backward in linear streSeek Cannot Seek failed
Seek failed
Seek failed
Seek failed
Seek failed
Seek failed
Seek failed
Seek failed
Seek failed
Seek failed
Seek failed
Seek failed
Seek failed
Seek failed
Seek failed
Seek failed
Seek failed
Seek failed
Seek failed
Seek failed
Seek failed
Seek failed
Failed to open VDPAU backend libvdpau_r600.so: cannot open shared object
file: No such file or directory
[vdpau] Error when calling vdp_device_create_x11: 1
AO: [pulse] Init failed: Connection refused
Failed to initialize audio driver 'pulse'
[AO_ALSA] alsa-lib: pulse.c:243:(pulse_connect) PulseAudio: Unable to
connect: Connection refused

[AO_ALSA] Playback open error: Connection refused
Failed to initialize audio driver 'alsa'
[AO OSS] audio_setup: Can't open audio device /dev/dsp: No such file or
directory
[AO_ALSA] alsa-lib: pulse.c:243:(pulse_connect) PulseAudio: Unable to
connect: Connection refused

[AO_ALSA] Playback open error: Connection refused
AO: [pulse] Init failed: Connection refused
[AO_ALSA] alsa-lib: pulse.c:243:(pulse_connect) PulseAudio: Unable to
connect: Connection refused

[AO SDL] Unable to open audio: No available audio device
DVB card number must be between 1 and 4
The selected video_out device is incompatible with this codec.
Try appending the scale filter to your filter list,
e.g. -vf spp,scale instead of -vf spp.
The selected video_out device is incompatible with this codec.
Try appending the scale filter to your filter list,
e.g. -vf spp,scale instead of -vf spp.
[VD_FFMPEG] DRI failure.
/14.58% (ratio: 28000->192000)
Selected audio codec: [mpg123] afm: mpg123 (MPEG 1.0/2.0/2.5 layers I,
II, III)
==========================================================================
[AO SDL] Samplerate: 48000Hz Channels: Stereo Format s16le
AO: [null] 48000Hz 2ch s16le (2 bytes per sample)
Starting playback...
Movie-Aspect is 1.33:1 - prescaling to correct movie aspect.
VO: [xv] 720x480 => 720x540 Planar YV12
[VO_XV] Shared memory not supported
Reverting to normal Xv.
[VO_XV] Shared memory not supported
Reverting to normal Xv.
A: 0.8 V: 1.3 A-V: -0.573 ct: 0.000 2/ 2 ??% ??% ??,?% 1 0

Anything interesting there?

Ed

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Re: PVR-500 frame size [ In reply to ]
On Sun, Jan 12, 2014 at 2:01 PM, Ed Beroset <beroset@mindspring.com> wrote:
> I've been using my PVR-500 with analog (composite) NTSC input for some years
> vlc. I had been using the "vlc pvr:///dev/video0" which worked, but
> recently vlc has dropped the pvr interface in favor of v4lc. Unfortunately,
> it means my external video can no longer be displayed. Searching for
> answers, I came across this bug report:
> https://trac.videolan.org/vlc/ticket/10258 which describes my symptoms
> exactly, but was closed as "not a vlc bug."

That ticket doesn't look relevant to the problem at hand. The user
used v4l:// instead of v4lc://. In other words, he tried to feed the
PVR-150's MPEG stream to a VLC input type that expected raw
uncompressed video.

That said, I'm not sure what your issue is. Do you have any VLC logs
you can post?

Devin

--
Devin J. Heitmueller - Kernel Labs
http://www.kernellabs.com

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Re: PVR-500 frame size [ In reply to ]
Devin Heitmueller wrote:
> On Sun, Jan 12, 2014 at 2:01 PM, Ed Beroset <beroset@mindspring.com> wrote:
>> I've been using my PVR-500 with analog (composite) NTSC input for some years
>> vlc. I had been using the "vlc pvr:///dev/video0" which worked, but
>> recently vlc has dropped the pvr interface in favor of v4lc. Unfortunately,
>> it means my external video can no longer be displayed. Searching for
>> answers, I came across this bug report:
>> https://trac.videolan.org/vlc/ticket/10258 which describes my symptoms
>> exactly, but was closed as "not a vlc bug."
>
> That ticket doesn't look relevant to the problem at hand. The user
> used v4l:// instead of v4lc://. In other words, he tried to feed the
> PVR-150's MPEG stream to a VLC input type that expected raw
> uncompressed video.

I'm not sure I understand that. If that person was making an error,
it's probable I'm making the same one, since I've been attempting to use
v4l2:///dev/video0 just as that person was.

>
> That said, I'm not sure what your issue is. Do you have any VLC logs
> you can post?

I could, but perhaps it's a moot point. When I use "vlc
v4l2c:///dev/video:input=2" it works perfectly. When I use "vlc
v4l2:///dev/video:input=2" (which is what I'd been attempting up until
your message) I get the same errors as listed in ticket 10258.

So, I'm happy that a solution seems to be at hand, but vlc only showed
me v4l2:// devices under the heading "Capture Devices" and I did not
know of the existence of v4l2c:// devices until just now (and don't know
what they are.) Thank you for bridging the gap for me -- what can we do
to help the next person encountering this problem?

Ed

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Re: PVR-500 frame size [ In reply to ]
On Sun, Jan 12, 2014 at 7:20 PM, Ed Beroset <beroset@mindspring.com> wrote:
> I could, but perhaps it's a moot point. When I use "vlc
> v4l2c:///dev/video:input=2" it works perfectly. When I use "vlc
> v4l2:///dev/video:input=2" (which is what I'd been attempting up until your
> message) I get the same errors as listed in ticket 10258.
>
> So, I'm happy that a solution seems to be at hand, but vlc only showed me
> v4l2:// devices under the heading "Capture Devices" and I did not know of
> the existence of v4l2c:// devices until just now (and don't know what they
> are.) Thank you for bridging the gap for me -- what can we do to help the
> next person encountering this problem?

The root of the issue is that the V4L2 spec had some ambiguity, so
until very recently devices did a really bad job of advertising
whether they were providing compressed video or raw uncompressed video
(the issue was particularly bad in cases where a given device could
provide both). The use of "v4l2c://" explicitly tells VLC that the
PVR-150 is providing compressed video, which is why it works for you.
If you instead tell it "v4l2://" then you're telling VLC that the
device provides uncompressed video, which the PVR-150 doesn't support
- that's why you're getting the error.

Presumably drivers do a better job advertising what they support
nowadays (primarily as a result of work Hans Verkuil did over the last
year or so), so VLC should probably be changed such that specifying
"v4l2://" causes it to ask the driver whether the video is compressed,
and handle it accordingly. Then in the longer term the "v4l2c://"
method would be deprecated entirely.

Even there you probably want to add some sort of option to allow the
caller to specify which to use when a device supports both, since
there are advantages to each approach depending on what you're
ultimately doing with the video. For example, if you're streaming it
over a network then compressed is the better choice - unless you want
to stream it in H.264, in which case you're better doing uncompressed
so that you avoid the cost of decompressing the stream before
re-encoding it to H.264.

Long story short, none of this is really a problem with the IVTV
driver, and if you want to see VLC's logic improved then it would
probably makes sense to start a new thread over on the vlc-devel
mailing list.

Devin


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http://www.kernellabs.com

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