[FFmpeg-user] Need help to re-stream multicast

Wed Oct 28 19:51:55 EET 2020

On Wed, Oct 28, 2020 at 12:56 PM Karim SLIMANI <diffusepro at gmail.com> wrote:

> hello,
>
> i think you need to increase fifo_size parameter. (remove pkt_size and
> buffer_size parameters, but keep overrun_nonfatal=1)
>
> try a fifo_size=524288 if it continue to crash, then try a value of
> fifo_size=2621400
>
> Circular buffer overrun happen when the computer cannot catch up in
> processing received data, so increasing the size may help (ie: fifo_size)
> To understand what is happening here, take a look at
> https://github.com/FFmpeg/FFmpeg/blob/master/libavformat/udp.c#L500
>
> Best regards,
>
>
> Le mar. 27 oct. 2020 à 22:19, Daniel Dimitrov <596076 at gmail.com> a écrit :
>
> > Dear all,
> > I try to retransmit  multicast stream . I can partially manage to do it
> > unfortunately some interruptions in the stream appear , Please help me to
> > correctly calculate the parameters for the udp url (fifo_size ,
> > buffer_size,bitrate, pkt_size) i want to set video bitrate to 3M and i am
> > not sure if i have to do muxrate. Command is here :
> >
> > *ffmpeg -i
> > "udp://@
> >
> 238.252.250.9:5000?overrun_nonfatal=1&fifo_size=350000&pkt_size=1316&buffer_size=10000000
> > <
> >
> http://238.252.250.9:5000?overrun_nonfatal=1&fifo_size=350000&pkt_size=1316&buffer_size=10000000
> > >"
> >    -vf scale=720:576    -b:v 3M -maxrate 4M -bufsize 8M   -b:a 128k
> >  -muxrate 5M -f mpegts
> > "udp://@
> >
> 239.253.251.13:5505?overrun_nonfatal=1&fifo_size=350000&pkt_size=188&&buffer_size=2000000&bitrate=5000000
> > <
> >
> http://239.253.251.13:5505?overrun_nonfatal=1&fifo_size=350000&pkt_size=188&&buffer_size=2000000&bitrate=5000000
> > >"*
> >
> > i have doubts about most of the udp parameters so please correct me if
> > anything looks wrong to you.
> >
> > *Here is the input stream:*
> >
> > Input #0, mpegts, from 'udp://@238.252.250.9:5000':
> >   Duration: N/A, start: 31142.994278, bitrate: N/A
> >   Program 2002
> >     Metadata:
> >       service_name    : RT Doc HD
> >       service_provider: GLOBECAST
> >     Stream #0:0[0x7e5]: Video: h264 (High) ([27][0][0][0] / 0x001B),
> > yuv420p(tv, bt709, top first), 1920x1080 [SAR 1:1 DAR 16:9], 25 fps, 50
> > tbr, 90k tbn, 50 tbc
> >     Stream #0:1[0x7e6](eng): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz,
> > stereo, fltp, 192 kb/s
> >     Stream #0:2[0x7e7](eng): Audio: mp2 ([3][0][0][0] / 0x0003), 48000
> Hz,
> > stereo, fltp, 192 kb/s
> >
> >
> > * If i execute the command above it crashes after 5min with :*
> >
> >
> > [h264 @ 0x6b52480] reference picture missing during reorder
> >     Last message repeated 1 times
> > [h264 @ 0x6b52480] Missing reference picture, default is 65814
> >     Last message repeated 1 times
> > [h264 @ 0x6ad5380] reference picture missing during reorder
> > [h264 @ 0x6ad5380] Missing reference picture, default is 65815
> > Output #0, mpegts, to 'udp://@
> >
> >
> 239.253.251.13:5505?overrun_nonfatal=1&fifo_size=350000&pkt_size=188&&buffer_size=2000000&bitrate=4000000
> > ':
> >   Metadata:
> >     encoder         : Lavf58.45.100
> >     Stream #0:0: Video: mpeg2video (Main), yuv420p, 720x576 [SAR 64:45
> DAR
> > 16:9], q=2-31, 3000 kb/s, 25 fps, 90k tbn, 25 tbc
> >     Metadata:
> >       encoder         : Lavc58.91.100 mpeg2video
> >     Side data:
> >       cpb: bitrate max/min/avg: 4000000/0/3000000 buffer size: 2000000
> > vbv_delay: N/A
> >     Stream #0:1(eng): Audio: mp2, 48000 Hz, stereo, s16, 128 kb/s
> >     Metadata:
> >       encoder         : Lavc58.91.100 mp2
> >     Stream #0:2(eng): Audio: mp2, 48000 Hz, stereo, s16, 128 kb/s
> >     Metadata:
> >       encoder         : Lavc58.91.100 mp2
> > av_interleaved_write_frame(): Cannot allocate memory:18.08
> > bitrate=4995.0kbits/s speed=1.01x
> >     Last message repeated 1 times
> > Error writing trailer of udp://@
> >
> >
> 239.253.251.13:5505?overrun_nonfatal=1&fifo_size=350000&pkt_size=188&&buffer_size=2000000&bitrate=4000000
> > :
> > Cannot allocate memory
> > frame= 9427 fps= 25 q=2.8 Lsize=  230612kB time=00:06:18.24
> > bitrate=4994.6kbits/s speed=1.01x
> > video:138661kB audio:11807kB subtitle:0kB other streams:0kB global
> > headers:0kB muxing overhead: 53.263130%
> > [udp @ 0x682e200] Circular buffer overrun. Surviving due to
> > overrun_nonfatal option
> >     Last message repeated 121516 times
> > Conversion failed!
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Hi Karim ,
Thank you for your mail, Setting fifo_size to 2621400 did the job but I
still have some problems in the stream . I have an analyzer listening for
the output stream and it shows some errors in PAT and PMT every 30-40sec .
Tried different parameters and no luck. Please check the photo attached to
this mail and if any of you guys has any proposal please let me know.
ffmpeg command:

ffmpeg -i "udp://@238.252.250.9:5000?overrun_nonfatal=1&fifo_size=524288"
-map 0:0    -vf scale=720:576  -b:v 3M -minrate 3M -maxrate 5M   -map 0:2
-b:a 128k -map -0:1 -muxrate 7M  -threads 0 -f mpegts   "udp://@
239.253.251.13:5505?overrun_nonfatal=1&fifo_size=524288&bitrate=7000000&pkt_size=1316
"
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