[FFmpeg-user] Webcam capture with ffmpeg on Windows: need help with raw capture + preview window.
general at vultaire.net
Wed May 22 07:33:48 CEST 2013
I've been experimenting with ffmpeg as a replacement for the abysmal
webcam software provided with my Logitech web cam. I'm not an ffmpeg
pro by any means; I'm studying a lot though and have put in
significant effort to try to figure this out myself. Pointers would
be really helpful.
Basically, I'm trying to do a "raw" 720p webcam/microphone capture via
dshow, and am also trying to hook in a preview window via ffplay.
My command line looks like this (line breaks inserted for readability):
ffmpeg -f dshow -rtbufsize 1000000k -s 1280x720 -r 30 \
-i video="Logicool HD Webcam C310":audio="マイク (Realtek High Definition Au" \
-vcodec copy -acodec copy -r 30 -threads 4 output.avi \
-s 426x240 -pix_fmt yuv420p -f rawvideo - \
| ffplay -f rawvideo -pixel_format yuv420p -video_size 426x240 -
And for completeness, my input streams look like:
Input #0, dshow, from 'video=Logicool HD Webcam C310:audio=繝槭う繧ｯ (Realtek High Definition Au':
Duration: N/A, start: 175477.576000, bitrate: 1411 kb/s
Stream #0:0: Video: rawvideo, bgr24, 1280x720, 30 tbr, 10000k tbn, 30 tbc
Stream #0:1: Audio: pcm_s16le, 44100 Hz, stereo, s16, 1411 kb/s
Problems encountered are:
1. ffplay output is delayed by a second or two.
2. output.avi gets cut off prematurely; this does not happen if I omit
piping to ffplay.
3. I get error messages such as "real-time buffer 62% full! frame
dropped!" after about 40 seconds. Without the ffplay stream, I do
not get this.
I'm not sure I've provided enough info, but would any of you have
suggestions for how to make this work?
- Paul Goins
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