[FFmpeg-user] cant stream audio and video at the same time

[Gisbert Haas]

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 
>> and know the content is safe.
>>
>>
>>>
>>> Am 05.01.2021 um 16:05 schrieb Gisbert Haas <gisbert.haas at myvinn.com 
>>> <mailto:gisbert.haas at 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