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DM365 Mpeg2 encoder compliance problem.

Samer Tufail
Prodigy 210 points

Hi,

Im using DVSDK 4.0.2, dm365 evm and mpeg2 encoder to perform create a DVB-S stream. A DVB-S stream requires a valid compliant mpeg2 stream ( later muxed to be TS). However using the ffmpeg mpeg2 encoder I was able to create a stream which was complaint (with further processing my own stuff) however with dm365 and dvsdk demos mpeg2 encoder I was not.

I decided to create two files with each encoder and analyze then on where the problem lies and I will post some images. It turns out that ffmpeg's mpeg2 encoder repeats frames of SEQUNCE - SEQUENCE EXTENSION - GOP , Every 14 frames as required by the MPEG 2 standard but dm365's mpeg2 encoder does not

Image showing sequence frames of ffmpeg mpeg2: http://postimage.org/image/f8si5u0wz/

Image Showing sequence frames of dm365 mpeg2: http://postimage.org/image/h8ay2soh1/

You can clearly see the differences between the streams. The analyzer also reports 55 (Fair) for dm365 stream and 80 (Excellent) for ffmpeg streams (should not make a difference but this is how the analyzer ranks it in terms of compliance).

Is there a reason for this implementation? , Is there a solution to this problem?

Thanks for your help.

Regards,

Sam

  • 0
    TI__Genius 17215 points

    Sorry for delayed response - below is what i managed to gather - 

    If it is looking for Intra frames and sequence headers every 15 frames then following solution will help

    1. Send generate header for every 15 calls. This can be done by dynParams->videncDynamicParams.generateHeader.
    2. Setting intraFrameInterval to 15. This is also part of dynParams.
    Regards
    Yashwant
  • 0 in reply to Yashwant Dutt
    Prodigy 210 points

    Hi Yashwant,

    Thanks for your response, the problem is the missing GOP structures within the stream. It is actually discussed here in a thread http://e2e.ti.com/support/embedded/multimedia_software_codecs/f/356/t/42309.aspx. The solution you mentioned above will generate seq headers but what of the GOP structure which would still be missing?. Any way around that?

    Best Regards,

    Samer Tufail

  • 0 in reply to Samer Tufail
    TI__Genius 17215 points

    We dont have B frame support in DM365 mpeg2 encoder.

     

    regards

    Yashwant