changing stream quality on the fly

[gobris]

Which version are you using?

v0.12.2

Which operating system are you using?

Windows

Question

I am trying to stream a video from a video capture card.
paths:
cam:
runOnInit: ffmpeg -f dshow -i video="AV TO USB2.0" -f rtsp rtsp://localhost:$RTSP_PORT/$RTSP_PATH
runOnInitRestart: yes
command makes it work.
But I want to do two things.
First I want to change the frame rate of the streaming video.. it is default 30 frames..

Output #0, rtsp, to 'rtsp://localhost:8554/cam':
Metadata:
encoder : Lavf58.64.100
Stream #0:0: Video: mpeg4, yuv420p(tv, progressive), 720x480, q=2-31, 200 kb/s, 30 fps, 90k tbn, 30 tbc
Metadata:
encoder : Lavc58.114.100 mpeg4
Side data:
cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: N/A
frame= 9585 fps= 30 q=31.0 size=N/A time=00:05:19.46 bitrate=N/A dup=1 drop=0 speed= 1x

Second, is it possible to change this stream to HLS on the fly and if yes how?

[aler9]

Hello, as written in the README, to re-encode it's enough to use the runOnPublish option, so to change fps to, for instance, 20:

paths:
  cam:
    runOnInit: ffmpeg -f dshow -i video="AV TO USB2.0" -f rtsp rtsp://localhost:$RTSP_PORT/$RTSP_PATH
    runOnInitRestart: yes
    runOnPublish: ffmpeg -i rtsp://localhost:$RTSP_PORT/$RTSP_PATH -c:v libx264 -preset ultrafast -b:v 500k -max_muxing_queue_size 1024 -filter:v fps=fps=20 -f rtsp rtsp://localhost:$RTSP_PORT/newfps
    runOnPublishRestart: yes

HLS is also written in the readme; since the previous configuration writes the new stream to the /newfps path, you can convert to HLS after changing the framerate, with:

paths:
  newfps:
    runOnPublish: ffmpeg -re -i rtsp://localhost:$RTSP_PORT/$RTSP_PATH -c copy -f hls -hls_time 1 -hls_list_size 3 -hls_flags delete_segments -hls_allow_cache 0 stream.m3u8
    runOnPublishRestart: yes

[gobris]

Thank you for fast response..
I just tried.
First conversion to 24frames.

cam: 
runOnInit: ffmpeg -f dshow -i video="AV TO USB2.0" -f rtsp rtsp://localhost:$RTSP_PORT/$RTSP_PATH
 runOnInitRestart: yes 
runOnPublish: ffmpeg -i rtsp://localhost:$RTSP_PORT/$RTSP_PATH -c:v libx264 -preset ultrafast -b:v 500k -max_muxing_queue_size 1024 -filter:v fps=fps=20 -f rtsp rtsp://localhost:$RTSP_PORT/newfps 
runOnPublishRestart: yes

and got error:

mpeg4 @ 000001f443acc540] warning: first frame is no keyframe
 [libx264 @ 000001f443aca400] using SAR=1/1:00:00.50 bitrate=N/A speed=0.976x 
[libx264 @ 000001f443aca400] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 
[libx264 @ 000001f443aca400] profile Constrained Baseline, level 3.0, 4:2:0, 8-bit 
[libx264 @ 000001f443aca400] 264 - core 161 - H.264/MPEG-4 AVC codec - Copyleft 2003-2020 - http://www.videolan.org/x264.html - options: cabac=0 ref=1 deblock=0:0:0 analyse=0:0 me=dia subme=0 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=15 lookahead_threads=2 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=0 keyint=250 keyint_min=20 scenecut=0 intra_refresh=0 rc=abr mbtree=0 bitrate=500 ratetol=1.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=0
 2020/12/07 10:47:15 [3/1/1] [client [::1]:60123] connected 
2020/12/07 10:47:15 [3/1/1] [client [::1]:60123] OPTIONS 
2020/12/07 10:47:15 [3/1/1] [client [::1]:60123] ANNOUNCE 
2020/12/07 10:47:15 [3/1/1] [client [::1]:60123] ERR: unable to find a valid configuration for path 'newfps' 
2020/12/07 10:47:15 [2/1/1] [client [::1]:60123] disconnected Could not write header for output file #0 (incorrect codec parameters ?): Server returned 400 Bad Request Error initializing output stream 0:0 -- 
[libx264 @ 000001f443aca400] final ratefactor: 27.11

then instead of changing frame rate.. wanted to switch to hls directly.. and assumed.. instad of newfps I need to write it down in cam path.

So new config seems like;

cam: 
runOnInit: ffmpeg -f dshow -i video="AV TO USB2.0" -f rtsp rtsp://localhost:$RTSP_PORT/$RTSP_PATH 
runOnInitRestart: yes
 runOnPublish: ffmpeg -re -i rtsp://localhost:$RTSP_PORT/$RTSP_PATH -c copy -f hls -hls_time 1 -hls_list_size 3 -hls_flags delete_segments -hls_allow_cache 0 stream.m3u8 
runOnPublishRestart: yes

Now, output screen shows as;

Metadata: title : Stream Duration: N/A, start: 0.000000, bitrate: N/A Stream #0:0: Video: mpeg4 (Simple Profile), yuv420p, 720x480 [SAR 1:1 DAR 3:2], 30 tbr, 90k tbn, 30 tbc Output #0, hls, to 'stream.m3u8': 
Metadata: title : Stream encoder : Lavf58.64.100 Stream #0:0: 
Video: mpeg4 (Simple Profile), yuv420p, 720x480 [SAR 1:1 DAR 3:2], q=2-31, 30 tbr, 90k tbn, 30 tbc Stream mapping: Stream #0:0 -> #0:0 (copy) 
Press [q] to stop, [?] for help 
[hls @ 000001eac2c1ba80] Opening 'stream0.ts' for writingate=N/A speed=0.992x 
[hls @ 000001eac2c1ba80] Opening 'stream.m3u8.tmp' for writing
 [hls @ 000001eac2c1ba80] Opening 'stream1.ts' for writingate=N/A speed=1.03x 
[hls @ 000001eac2c1ba80] Opening 'stream.m3u8.tmp' for writing
 [hls @ 000001eac2c1ba80] Opening 'stream2.ts' for writingate=N/A speed=0.997x
 [hls @ 000001eac2c1ba80] Opening 'stream.m3u8.tmp' for writing 
[hls @ 000001eac2c1ba80] Opening 'stream3.ts' for writingate=N/A speed=1.02x
 [hls @ 000001eac2c1ba80] Opening 'stream.m3u8.tmp' for writing
 [hls @ 000001eac2c1ba80] Opening 'stream4.ts' for writingate=N/A speed=0.996x 
[hls @ 000001eac2c1ba80] Opening 'stream.m3u8.tmp' for writing
 [hls @ 000001eac2c1ba80] Opening 'stream5.ts' for writingate=N/A speed=1.01x
 [hls @ 000001eac2c1ba80] Opening 'stream.m3u8.tmp' for writing
 [hls @ 000001eac2c1ba80] Opening 'stream6.ts' for writingate=N/A speed=1.01x 
[hls @ 000001eac2c1ba80] Opening 'stream.m3u8.tmp' for writing 
[hls @ 000001eac2c1ba80] Opening 'stream7.ts' for writingate=N/A speed=1.01x 
[hls @ 000001eac2c1ba80] Opening 'stream.m3u8.tmp' for writing
 [hls @ 000001eac2c1ba80] Opening 'stream8.ts' for writingate=N/A speed=1.01x
 [hls @ 000001eac2c1ba80] Opening 'stream.m3u8.tmp' for writing 
[hls @ 000001eac2c1ba80] Opening 'stream9.ts' for writingate=N/A speed=1.01x 
[hls @ 000001eac2c1ba80] Opening 'stream.m3u8.tmp' for writing
 [hls @ 000001eac2c1ba80] Opening 'stream10.ts' for writingte=N/A speed= 1x
 [hls @ 000001eac2c1ba80] Opening 'stream.m3u8.tmp' for writing 
[hls @ 000001eac2c1ba80] Opening 'stream11.ts' for writingte=N/A speed= 1x 
[hls @ 000001eac2c1ba80] Opening 'stream.m3u8.tmp' for writing [hls @ 000001eac2c1ba80] Opening 'stream12.ts' for writingte=N/A speed=1.01x 
[hls @ 000001eac2c1ba80] Opening 'stream.m3u8.tmp' for writing frame= 557 fps= 30 q=-1.0 size=N/A time=00:00:18.90 bitrate=N/A speed= 1x

and keeps on increasing..
And couldnt connect to stream with
http://192.168.1.2:8554/cam/stream.m3u8 (maybe it is wrong path)
Or maybe source should be x264 instead of mpeg for HLS..
And not converting it causes the problem.