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Table of Contents
Video capture on Linux
Capture cards
- Easy Cap DC60 Aliexpress product page
If you have issues with this card (dmesg yelling that it's a model with the generic USB PVID), you need either to reload the kernel module with modprobe em28xx card=64, or adding options em28xx card64 to /etc/modprobe.d/easycap-em28xx.conf, but this will screw with other capture cards using the eMPIA em28xx controllers.
| Input | Works? |
|---|---|
| S-Video | Yes, OOB, in color (input=0) |
| Composite | Yes, OOB, (input=1) |
| Audio | Muted by default, need to be unmuted with v4lctl |
Remarks:
- All settings need to be preset with v4lctl, setting format and framerate with ffmpeg will fail with the following error:
ioctl(VIDIOC_S_PARM): Inappropriate ioctl for device em28xx. - Signal integrity is satisfactory, no specific remarks to add.
Monitoring video signal
You can do this in realtime using the following commands:
Display NTSC:
ffmpeg -f v4l2 -standard NTSC -video_size ntsc -framerate ntsc -i /dev/video2 -f alsa -i hw:1,0 -vcodec ayuv -acodec copy -map 0:0 -map 1:0 -f avi pipe:1 | ffplay -
Display PAL:
ffmpeg -f v4l2 -standard PAL -video_size pal -framerate pal -i /dev/video2 -f alsa -i hw:1,0 -vcodec ayuv -acodec copy -map 0:0 -map 1:0 -f avi pipe:1 | ffplay -
If your card doesn't support VIDIOC_S_PARM ioctls:
ffmpeg -f v4l2 -i /dev/video2 -f alsa -i hw:1,0 -vcodec ayuv -acodec copy -map 0:0 -map 1:0 -f avi pipe:1 | ffplay -
Capturing video signal
checklist:
Unless you have a decent machine, it is recommended to first save an uncompressed capture that you will process in a second time for compression (either lossless for mastering, or lossy for final consumption).
Lossy content encoding
- Transparent, x264
ffmpeg -i master.avi -c:v libx264 -preset slow -crf 18 -c:a opus -b:a 192 output.mkv
- Transparent, x265
ffmpeg -i master.avi -c:v libx265 -preset slow -crf 24 -c:a opus -b:a 192 output.mkv
Additionally, you should tune the encoder by inserting -tune <option> depending on the kind of content you're encoding:
| Option | Target |
|---|---|
| film | use for high quality movie content; lowers deblocking |
| animation | good for anime and cartoons; uses higher deblocking and more reference frames |
| grain | preserves the grain structure in old, grainy film material |
| stillimage | good for slideshow-like content |
If you wish to have a smaller file, you can tune the CRF up to 28 for x264, and for x265.