[FFmpeg-user] Newbie needs help on capture video/audio using ffmpeg on RPI

Tom Sparks tomasparks.ts at gmail.com
Thu May 14 17:28:02 EEST 2020

On 14/05/2020, Ram Shaffir <ram at ram.sh> wrote:
> My "success" wasn't as good as I thought when capturing the video feed for
> over 15 seconds or so I get an error and the although the output video size
> keeps on growing there are no new frames only audio:
> ffmpeg -y -f alsa -thread_queue_size 15000 -ac 2 -itsoffset -0.5 -i hw:1,0
> -f v4l2 -thread_queue_size 15000 -i /dev/video0 -acodec ac3 -ab 51k -s
> 896x504 -r 30 -vcodec libx264 -b:v 2100K -pix_fmt yuv422p -f mp4
> /usr/ramDisk/libx264.mp4
> Input #1, video4linux2,v4l2, from '/dev/video0':
>   Duration: N/A, start: 53746.367981, bitrate: 1988671 kb/s
> Stream #1:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422, 1920x1080,
> 1988671 kb/s, 59.94 fps, 59.94 tbr, 1000k tbn, 1000k tbc

You are trying to convert a RAW 1080p @ 60fps (1988671 kb/s) stream to
h.264 504p @ 30fps (2100Kb/s), the raspberry PI *DOES NOT* have the
CPU power and the USB bus cant handle 248.583875 Mbytes/s

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