I swear that ffmpeg will drive even the most easy going man totally insane!
Anyway, post rant...I have an HD logitech webcam (Webcam C310) and I'm trying to save workstation sessions so I can create online tutorials. To do this I need to save content in a low-loss format. I chose mjpeg with quality value 2 and pcm_s16le audio at 44.1khz. I'm trying to do 1280x720 proof format and scale down after editing. That format IS SUPPORTED at 25 and 30fps by my webcam.
The booger is that the exact same ffmpeg recording command will about 50% of the time create a compressed audio stream of up to five minutes, while the video is going on well longer (tested up to 20 minute clip)
Sometimes the audio is correct and sometimes just chipmunks squeeking.
Here is the command
#! /bin/bash
out=${1-~/record.mov}
ffmpeg \
-y \
-f pulse \
-i default \
-f v4l2 \
-input_format mjpeg -video_size 1280x720 -framerate 25 \
-i /dev/video0 -c:v mjpeg -q:v 2 -ac 2 -c:a pcm_s16le -ar 44100 \
${out}
When it works the audio is only one or two frames off, but it fails more
often than it is correct.
Another weird symptom is that I see regular periodic clusters of a video frame repeating itself 14 times, which obviously shows up when viewing.
anybody have alternate recipes for 720p A/V capture from a USB2 webcam that supports MJPEG?
I am considering running audio save to a separate file (arecord for audio and ffmpeg for video) and muxxing them in cinelerra later on, but obviously would prefer it work out of the box.
OpenPGP_0x36472CAD382840B8.asc
Description: OpenPGP public key
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Description: OpenPGP digital signature
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