[FFmpeg-user] MPEG-2 CBR

[Roger Pack]

On 1/22/15, Janez Miklavcic <svislartv at gmail.com> wrote:
> 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.


Let us know if you find the problem in FFmpeg then, patches welcome!
>
>
>
> 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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