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40 lines
1.6 KiB
40 lines
1.6 KiB
4 years ago
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By Peter Chiocchetti <pch14 at myzel dot net>
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DV only supports two resolutions: 720x576 for PAL, and 720x480
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for NTSC. Possibly, there is also 1920x1080.
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transcode allows other frame sizes too; playing these back in
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other applications will show as split images, or rolling
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seemingly random colours.
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libdv can be compiled to use either YUY2 or YV12 modes for PAL
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video, but there is no function for libdv to tell you which
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one it's using... so transcode runs a test frame through the
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decoder and tries to guess based on the result. If it gets it
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wrong, you can use either --dv_yuy2_mode or --dv_yv12_mode to
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force one or the other. The libdv default is YUY2.
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If the bar is only some pixels wide, you should be able to
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crop the image, and uncrop it again, adding black borders,
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instead of green ones - be sure the frame stays at the above
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sizes. Such a bar may be the result of a sampling error in the
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capture card or even in signal transmission.
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If you want to display on TV, you need not care of few green
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pixels at the bottom at all, as about 0 - 10% of the image
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will be offscreen anyways - the region TV sets and beamers
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display is closer to 640x480 than to 720x576 for PAL systems
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- see eg. the title-safe region in editing software.
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Example:
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This line captures from a pal source to pal dv and crops 64
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pixels from the bottom and adds it again as solid black -
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obviously the clipping params are non-intuitively, shouldnt
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the sequence be t,l,b,r?
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transcode -q 2 -x v4l2 -i /dev/video0 \
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-p /dev/dsp -g 720x576 -j 64,0,0,0 \
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-Y -64,0,0,0 -y dvraw="qno=2" -o rec.dv \
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-H 0 -n 0x1 -N 0x1 --uyvy --print_status 25
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