Linux Media Controller development
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From: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
To: Scott Doty <scott@ponzo.net>
Cc: Hans Verkuil <hverkuil@xs4all.nl>,
	Linux Media Mailing List <linux-media@vger.kernel.org>
Subject: Re: hdpvr.ko kernel 5.3-rc6
Date: Wed, 4 Sep 2019 15:40:01 -0300	[thread overview]
Message-ID: <20190904154001.6a6109f9@coco.lan> (raw)
In-Reply-To: <75f04282-7625-4c7e-7e94-c45195a152b5@ponzo.net>

Em Wed, 4 Sep 2019 11:13:36 -0700
Scott Doty <scott@ponzo.net> escreveu:

> On 9/3/19 1:34 AM, Hans Verkuil wrote:
> >
> > Never mind, hdpvr uses read(), not streaming I/O. Of course this
> > doesn't work...
> >
> > Just plain 'cat /dev/videoX >x.mpg' will do.
> >
> >  
> 
> Okay, tried that, it produces data that vlc can then play back.
> 
> So I think I'm running into a problem with vlc instead of hdpvr. It's 
> just weird that mplayer, vlc, and ffplay would all three be unable to 
> use it.

You can use any of them, provided that it is opened as if it were a
normal file, using the read() interface. For example, this should work:

	cat /dev/videoX | mplayer -cache 8000 -

The thing is that most apps assume that a V4L2 device supports mmap().

This is true for almost all devices, being hdpvr - and pvrusb - two
exceptions.


Thanks,
Mauro

  reply	other threads:[~2019-09-04 18:40 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-02  1:02 hdpvr.ko kernel 5.3-rc6 Scott Doty
2019-09-02  7:31 ` Hans Verkuil
2019-09-03  3:45   ` Scott Doty
2019-09-03  6:35     ` Hans Verkuil
2019-09-03  8:34       ` Hans Verkuil
2019-09-04 18:13         ` Scott Doty
2019-09-04 18:40           ` Mauro Carvalho Chehab [this message]
2019-09-05  7:15             ` Scott Doty
2019-09-05  6:59           ` Scott Doty

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