[FFmpeg-user] MPEG-2 CBR

[Janez Miklavcic]

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


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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