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MPEG4 decoder

Hello,

I have MPEG4 decoder questions:

1) How to get aspect ratio of current frame

2) Can this table be moved to MSMC memory or the values differ for each MPEG4 decoder instance?

0085fae8    00001170     m4h3dec_ti.le66 (.fardata:M4H3DEC_TI_DCTAC_NMIDRATEIntrqMD_Table_AnnexI:vldTables.oc)

I use this decoder: software-dl.ti.com/.../index_FDS.html

Regards,

Andrey Lisnevich

  • Another issue - initialization of the codec fails on Full HD resolution (1920x1080). algAlloc returns -3. Do you know the reason?

    Thanks in advance,
    Andrey Lisnevich

  • Hi Andrey,

    >>>1) How to get aspect ratio of current frame

    You can get the storage aspect ratio ( which is the ratio of pixel dimensions ) using status->outputWidth/status->outputHeight.

    >>>2) Can this table be moved to MSMC memory or the values differ for each MPEG4 decoder instance?

    Yes, this table can be moved to MSMC memory.

    >>>3) initialization of the codec fails on Full HD resolution (1920x1080). algAlloc returns -3. Do you know the reason?

    The current implementation of decoder will support decoding only up to WVGA resolution.

    Please let us for any questions

    Thanks,

    Praveen.

  • Hi Praveen,

    Storage Aspect Ratio (SAR) is fine. It is just width and height in pixels. What I need is Display Aspect Ratio (DAR) or Pixel Aspect Ratio (PAR also called Sample Aspect Ratio in H.264 terminology).

    For example C66x MPEG-2 decoder has:
    IVIDDEC2_Status.aspect_ratio

    and C66x H.264 decoder has:
    IH264HPVDEC_OutArgs.SeiVui_buffer.vui_params.aspect_ratio_idc
    IH264HPVDEC_OutArgs.SeiVui_buffer.vui_params.sar_width
    IH264HPVDEC_OutArgs.SeiVui_buffer.vui_params.sar_height

    Regards,
    Andrey Lisnevich
  • Hi Andrey,


    For MPEG-2 decoder and H.264 decoder, these aspect ratio parameters have been parsed from the bit-stream and also those were populated in status or outArgs to send it to the application. Where as in MPEG-4 decoder these parameters were parsed from the bit stream but not populated in either status or outAgrs to send it to application.

    We will modify the MPEG-4 decoder library to support this feature and we will share the updated library.

    Thanks,

    Praveen

  • Hi Andrey,

    We extended the status structure to get the aspect ratio parameters from the library and also updated the library to populate these aspect ratio parameters in the status. Please find attached the updated library along with one modified header file .

    Mpeg4_Decoder_Lib_05262015.zip 

    With the updated MPEG-4 decoder we can get the aspect ratio parameters from the status as:
    IVIDDEC2_Status.aspect_ratio_info
    IVIDDEC2_Status.par_width
    IVIDDEC2_Status.par_height

    Please let me know for any questions

    Thanks,

    Praveen

  • Hi Andrey, wondering if library shared by Praveen worked OK for you?thank you,
    Paula
  • Andrey, I will close this E2E. Please let us know if you face any issue with previously shared library. Thank you,
    Paula