[FFmpeg-user] h254 -> av1 with VAAPI ?

[lejeczek]

Hi guys.

I'm trying to transcode a stream from a smartphone into a file:

-> $ ffprobe rtsp://192.168.1.125:8080/video/h264
...
   Duration: N/A, start: -3627.773756, bitrate: N/A
   Stream #0:0: Video: h264 (Constrained Baseline), 
yuv420p(progressive), 3840x2160, 90k tbr, 90k tbn

-> $ ffmpeg -hwaccel vaapi -hwaccel_device 
/dev/dri/renderD128 -hwaccel_output_format vaapi -i 
rtsp://192.168.1.125:8080/video/h264 -avoid_negative_ts 
make_zero -fflags +genpts -c:v av1_vaapi -b:v 8M av1-h264.mp4 -y
...
     encoder         : Lavf61.7.100
   Stream #0:0: Video: av1 (Main) (av01 / 0x31307661), 
vaapi(tv, progressive), 3840x2160, q=2-31, 8000 kb/s, 24.58 
fps, 18880 tbn
       Metadata:
         encoder         : Lavc61.19.101 av1_vaapi
frame=   32 fps= 32 q=-0.0 size=    1024KiB time=01:31:29.32 
bitrate=   1.5kbits/s dup=0 drop=2 speed=5.49e+03x   
frame=   44 fps= 29 q=-0.0 size=    1280KiB time=01:31:29.81 
bitrate= 1.9kbits/s dup=0 drop=2 speed=3.66e+03x   frame=   
58 fps= 29 q=-0.0 size=    1792KiB time=01:31:30.38 
bitrate=   2.7kbits/s dup=0 drop=2 speed=2.74e+03x   
frame=   82 fps= 27 q=-0.0 size= 2560KiB time=01:31:31.36 
bitrate=   3.8kbits/s dup=0 drop=2 speed=1.83e+03x   
frame=   94 fps= 27 q=-0.0 size=    3072KiB time=01:31:31.85 
bitrate=   4.6kbits/s dup=0 drop=2 speed=1.57e+03x   frame=  
106 fps= 26 q=-0.0 size=    3584KiB time=01:31:32.33 
bitrate=   5.3kbits/s dup=0 drop=2 speed=1.37e+03x   frame=  
118 fps= 26 q=-0.0 size=    3840KiB time=01:31:32.82 
bitrate=   5.7kbits/s dup=0 drop=2 speed=1.22e+03x   frame= 
1003 fps= 25 q=-0.0 size=   38656KiB time=01:32:08.82 
bitrate=  57.3kbits/s dup=0 drop=7 speed= 136x

I'm thinking - being a complete novice - it has something to 
do with the original stream (as opposed to VAAPI) for only 
'ffplay' does play the output file fine.
Any other player shows time duration for the output - being 
under a minute of recording - to be an hour & a half long.
Playback does not work unless I move manually towards the 
end, toward that last minute, then it starts to playback.

Any advice much appreciated.
many thanks, L.