Quoting Diego Simak <diego.simak@xxxxxxxxx>:
- Audio and video are not in sync, I can see the following message
after executing the ffmpeg command:
[swscaler @ 0x1ac5080] Warning: data is not aligned! This can lead to
a speedloss
diego@ruidosa:~$ ffmpeg -fflags +genpts+igndts -f x11grab -vsync 0 -r
30 -s 1366x768 -i :0.0+0,0 -vcodec h264 -f jack -ac 2 -r:a 48000 -i
screencast -acodec pcm_s16le -r:v 30 -vsync 2 -async 1 -map 0:0,1,0
-map 1:0 -preset ultrafast -qp 0 aaa.mkv
Duration: N/A, start: 1376226919.464630, bitrate: 1007124 kb/s
Stream #0:0: Video: rawvideo (BGR[0] / 0x524742), bgr0, 1366x768,
1007124 kb/s, 30 tbr, 1000k tbn, 30 tbc
jack_port_get_latency_range called with an incorrect port 0
[jack @ 0x1afbce0] JACK client registered and activated (rate=48000Hz,
buffer_size=1024 frames)
Guessed Channel Layout for Input Stream #1.0 : stereo
Input #1, jack, from 'screencast':
Duration: N/A, start: 1376226919.619355, bitrate: 3072 kb/s
Stream #1:0: Audio: pcm_f32le, 48000 Hz, stereo, flt, 3072 kb/s
[swscaler @ 0x1ac5080] Warning: data is not aligned! This can lead to
a speedloss
frame= 122 fps= 23 q=-1.0 Lsize= 2774kB time=00:00:04.06
bitrate=5588.3kbits/s
video:2040kB audio:732kB subtitle:0 global headers:0kB muxing
overhead 0.097703%
A couple of things :
* 1366 isn't a multiple of 8 which is probably why you get the "data
is not aligned! This can lead to a speedloss" warning. Set it to 1360
instead.
* You've set ffmpeg to record at 30 fps but it seems your computer can
only manage to do 23 fps. That might be the cause of the A/V being out
of sync.
Either decrease the capture area, change "-r:v 30" to something like
"-r:v 20" or try doing an uncompressed recording (replace "-vcodec
h264 -preset ultrafast -qp 0" with something like "-vcodec huffyuv").
In the latter case you'll end up with a really big capture file which
you might want/need to demux, compress and remux afterwards.
- Peder
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