Re: [Mlt-devel] Git: Fix video4linux in avformat producer.
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From: Dan D. <da...@de...> - 2011-02-22 00:48:42
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On Mon, Feb 21, 2011 at 4:39 PM, Dan Dennedy <da...@de...> wrote: > On Mon, Feb 21, 2011 at 3:12 PM, Hungerburg <pc...@my...> wrote: >> Am 2011-02-20 06:39, schrieb Dan Dennedy: >>> New commits: >>> commit a71c827644ff0acc38da80e080b0ed596acb3308 >>> Author: Dan Dennedy<da...@de...> >>> Date: Sat Feb 19 21:39:54 2011 -0800 >>> >>> Fix video4linux in avformat producer. >>> >>> melt video4linux2:/dev/video0 >>> >> >> Works for me. >> >> Currently I only have a very cheap device that is limited in its >> abilities. Two points to correct for that: >> >> 1) The MLT_PROFILE has to specify a setting that the device/driver can >> successfully use. Otherwise melt reports: Failed to load "video4linux2". > > The requirement for an explicit profile is by design at the moment as > there is no support for probing the v4l2 device capabilities. Also, > one can use -profile on the melt command line instead of environment > var. > >> 2) LD_PRELOAD=/usr/lib/libv4l/v4l2convert.so and >> LD_PRELOAD=/usr/lib/libv4l/v4l1compat.so are my friends. >> >> Below command line gets me some kind of delayed mirror: >> >> $ LD_PRELOAD=/usr/lib/libv4l/v4l2convert.so MLT_PROFILE=quarter_15 melt >> video4linux2:/dev/video0 -filter frei0r.flippo:"X axis=1" "Y axis=0" Here is one that shows more options: melt -profile square_ntsc video4linux2:/dev/video0?frame_rate:5\&width:640\&height:480 force_progressive=1 -filter frei0r.flippo "X axis"=1 -consumer sdl_still real_time=0 frame_rate_num=5 frame_rate_den=1 set force_progressive=1 to prevent the possibility of something incorrectly indicating not progressive. See also how to change the frame_rate - both in the v4l2 url and on the consumer to override the profile. Finally, I am using the sdl_still consumer to keep the RGB output of the frei0r filter and not output any audio (necessary at the moment for < 6 fps). Why 5fps? Even tho my webcam says it is capable of up to 30 fps, qv4l2 from v4l-utils always shows the fps is 5 in its capture window regardless what I set fps to. Also, I see no apparent change in framerate or faster shutter when I choose a higher fps. These webcams lie! -- +-DRD-+ |