ffmpeg
fast-forward mpeg? Not really. ffmpeg man page, use with webcam.
Prerequisites
Know thyself.
Identify the audio recording devices available
with pacmd list-sources.
I picked alsa_input.usb-046d_HD_Pro_Webcam_C920_CDF1191F-02.analog-stereo.
Identify the video formats available using…
v4l2-ctl --list-formats-ext -d /dev/video4
or
ffmpeg -f v4l2 -list_formats all -i /dev/video0
I picked MJPG 1920x1080.
Recording
This will:
- capture 10 seconds of video and audio
- video from
/dev/video4, at 30 fps, in MJPG format, at resolution 1920x1080 - audio from
alsa_card.usb-046d_HD_Pro_Webcam_C920_CDF1191F-02 - then compress video using
libx264withfasterpreset - compress audio using codec
ac3_fixed - and, finally, save it as
out.mkv, overwriting it if the one exists:
ffmpeg -y \
-f v4l2 -t 10 -framerate 30 -video_size 1920x1080 -input_format mjpeg -i /dev/video4 \
-f pulse -t 10 -sample_rate 44100 -channels 1 -i alsa_input.usb-046d_HD_Pro_Webcam_C920_CDF1191F-02.analog-stereo \
-c:v libx264 -preset faster -c:a ac3_fixed \
-metadata title="From my desk" out.mkv
To avoid re-compression:
ffmpeg -f v4l2 -framerate 30 -video_size 1280x720 -input_format mjpeg \
-i /dev/video0 -c copy out.mkv
Then…
Take a picture
ffmpeg -f v4l2 -video_size 1280x720 -i /dev/video0 -frames 1 out.jpg
Streaming
More Utilities
Use ffprobe to display stream info:
ffprobe out.mkv
Simple player:
ffplay /dev/video0
Trimming / Extraction
To cut out 20 seconds starting from 1:50 minutes, use:
ffmpeg -i input.mkv -ss 00:01:50 -c copy -t 20 output.mkv
The -ss option can be placed in front of -i, resulting in faster copying
but less accuracy. If you experience out-of-sync audio or video, you will have
to have to re-encode:
ffmpeg -i input.mkv -ss 00:01:50 -c:v libx264 -c:a libfaac -t 20 output.mkv