[FFmpeg-user] MPEG-2 CBR

[Janez Miklavcic]

Sorry for my late reply...

I've tested different settings and different hardware (IP to ASI converter
Dektec...) equipment and I found out problem is in ffmpeg.
The problem is greater if picture is moving but if am sending still picture
the problem is minor.
Also I found out that some STBs are sensitive to this problem other are not
sensitive at all.
I think it is not a problem of packet loss - hardware is connected to PC,
maybe it is a problem of PCR or audio bitrate changes.



2015-01-15 21:56 GMT+01:00 Roger Pack <rogerdpack2 at gmail.com>:

> On 1/15/15, Janez Miklavcic <svislartv at gmail.com> wrote:
> > Thank you for your help!
> >
> > The fact is taht when using hardware encoder and you set mux rate to
> > 20Mbit/s and video to 2Mbit/s the "space" between 2 Mbit and 20 Mbit/s
> will
> > be filled with null packets, this is not in this case.
> > Now I reduced Mux rate and it is not exceeded by the tests I did with TS
> > reader. But still this encoder doesn't behave like a hardware one, but no
> > problem.
> > Please note, that I use this multicast stream for input into the hardware
> > multiplexer.
> >
> > The other problem that I have with the same video settings is when I add
> > audio stream. When I add audio stream there are problems on sound all the
> > time.
> > If I use the same settings but without video input it works without a
> > problem.
> > The problem is only on hardware (all that I tested), it works on VLC with
> > no problem.
> >
> >
> > Here is commandline:
> >
> > f:/ffmpeg/bin/ffmpeg.exe -f dshow -video_size 720x576 -framerate 2
> > -pixel_format bgr24 -i video="VidBlaster VVD" -i udp://232.8.8.11:5002
> > -acodec mp2 -ar 48000 -b:a 192k -mpegts_service_id 0x002 -vcodec
> mpeg2video
> > -b:v 500k -minrate:v 500k -maxrate:v 500k -bufsize:v 1024k -s: 720x576 -f
> > mpegts -r 10 -g 30 -muxrate 1.5M -mpegts_pmt_start_pid 0x3E8
> > -mpegts_start_pid 0x3E9 -metadata service_name="POLANC TV INFO" -metadata
> > service_provider="SVISLAR telekom d.o.o." udp://
> > 232.8.8.8:55002?pkt_size=188&buffer_size=6M
>
> You're sending and receiving over udp, possibly packet loss explains
> your problem somehow...is there a way to tell if the packet loss is
> incoming or outgoing?
> >
> >
> > 2015-01-15 13:17 GMT+01:00 Claudiu Rad-Lohanel <jazzman at misalpina.net>:
> >
> >>
> >> On 1/15/2015 1:30 PM, Janez Miklavcic wrote:
> >>
> >>> f:/ffmpeg/bin/ffmpeg.exe -f dshow -video_size 720x576 -framerate 25
> >>> -pixel_format bgr24 -i video="VidBlaster VVD" -mpegts_service_id 0x002
> >>> -metadata service_name="POLANC TV INFO" -metadata
> >>> service_provider="SVISLAR
> >>> telekom d.o.o." -vcodec mpeg2video -b:v 2000k -minrate:v 2000k
> >>> -maxrate:v
> >>> 2000k -bufsize 200000k -q 3 -s: 720x576 -r 25 -g 50 -f mpegts
> >>> -mpegts_pmt_start_pid 0x3E8 -mpegts_start_pid 0x3E9 -muxrate 20M udp://
> >>> 232.8.8.8:55002?pkt_size=188
> >>>
> >>
> >> what's this? what would you expect it to do if you tell it to go at
> >> 20Mbit?
> >>
> >> -muxrate 20M
> >>
> >>
> >>
> >>> Although bitrate is set to 2Mbit/s it jumps to 20 Mbit/s.
> >>>
> >>> Thnaks,
> >>> Janez
> >>>
> >>> 2015-01-15 12:03 GMT+01:00 Roger Pack <rogerdpack2 at gmail.com>:
> >>>
> >>>  On 1/14/15, Janez Miklavcic <svislartv at gmail.com> wrote:
> >>>>
> >>>>> Dear All,
> >>>>>
> >>>>> I've been trying to achive constant video bitrate for mpeg-2 with
> >>>>>
> >>>> different
> >>>>
> >>>>> settings of ffmpeg (windows) but no success.
> >>>>> The source was dshow.
> >>>>> I've been testing video bitrate with TS reader.
> >>>>> Can you tell me if video CBR in MPEG-2 is possible or not and if yes
> >>>>> can
> >>>>> you send me the settings.
> >>>>>
> >>>> uncut command line and console output of failing example please?
> >>>> _______________________________________________
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> >>>
> >>
> >> --
> >> jazzman
> >>
> >>
> >> _______________________________________________
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> >>
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