Hi again,
anyone got a bride idea what else I can try? Could it be a bug?
Thanks again
On 1/5/21 10:24 PM, Gisbert Haas wrote:
Hi,
as I tried to explain, on the link you provided I learned about the
v4l2 timestamps option "-ts abs" I'm now using:
Linux Mint Laptop:
ffmpeg -f alsa -i default -f v4l2 -input_format yuv420p -video_size
1280x720 -ts abs -i /dev/video0 -c:v libx264 -b:v 8M -c:a aac -f
mpegts udp://230.10.1.1:5700
Raspberry Pi 4, RasbianOS 32 bit
ffmpeg -f alsa -i default -f v4l2 -input_format yuv420p -video_size
1280x720 -ts abs -i /dev/video0 -c:v h264_v4l2m2m -b:v 8M -c:a aac -f
mpegts udp://230.10.1.1:5700
only difference between the two is the video output format due to
different architecture.
On Linux Laptop the start_time is now in sync (with -ts abs):
Input #0, alsa, from 'default':
Duration: N/A, start: 1609881042.036804, bitrate: 1536 kb/s
Stream #0:0: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
Input #1, video4linux2,v4l2, from '/dev/video0':
Duration: N/A, start: 1609881042.395996, bitrate: 147456 kb/s
Stream #1:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422,
1280x720, 147456 kb/s, 10 fps, 10 tbr, 1000k tbn, 1000k tbc
On the Raspberry Pi even with the -ts abs set, the start_time did not
change:
Input #0, alsa, from 'hw:2,0':
Duration: N/A, start: 1609881274.125326, bitrate: 1536 kb/s
Stream #0:0: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
Input #1, video4linux2,v4l2, from '/dev/video0':
Duration: N/A, start: 0.000000, bitrate: 884736 kb/s
Stream #1:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422,
1280x720, 884736 kb/s, 60 fps, 60 tbr, 1000k tbn, 1000k tbc
instead I'm getting an error:
[video4linux2,v4l2 @ 0x23d0440] Unknown timestamps
with using option -ts mono2abs the time stamps are not quite the same:
Input #0, alsa, from 'default':
Duration: N/A, start: 1609881635.974239, bitrate: 1536 kb/s
Stream #0:0: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
[video4linux2,v4l2 @ 0x1028850] Detected monotonic timestamps, converting
Input #1, video4linux2,v4l2, from '/dev/video0':
Duration: N/A, start: 1609851045.581055, bitrate: 294912 kb/s
Stream #1:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422,
640x480, 294912 kb/s, 60 fps, 60 tbr, 1000k tbn, 1000k tbc
I hope with the -ts option I'm using the right option as I cant find
anything else on v4l2 would modify the start_time
Thanks a lot
On 1/5/21 8:58 PM, Carl Eugen Hoyos wrote:
CAUTION: This email originated from outside of the organization. Do
not click links or open attachments unless you recognize the sender
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Am 05.01.2021 um 16:05 schrieb Gisbert Haas <gisbert.h...@myvinn.com
<mailto:gisbert.h...@myvinn.com>>:
Input #0, alsa, from 'hw:2,0':
Duration: N/A, start: 1609858998.181873, bitrate: 1536 kb/s
Stream #0:0: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
[video4linux2,v4l2 @ 0x32cd6e0] Dequeued v4l2 buffer contains
corrupted data (0 bytes).
Input #1, video4linux2,v4l2, from '/dev/video0':
Duration: N/A, start: 0.000000, bitrate: 884736 kb/s
These streams cannot get synchronised because of the different start
times.
See https://ffmpeg.org/ffmpeg-devices.html#Options-18
Please find out what top-posting means and avoid it here.
And please do not reply in private to emails sent to a mailing list.
Carl Eugen
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