[FFmpeg-user] MPEG-2 CBR

Roger Pack rogerdpack2 at gmail.com
Thu Jan 15 21:56:24 CET 2015


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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