Latest post Mon, Jan 11 2016 7:38 PM by joelatakoo. 16 replies.
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  • Fri, Feb 27 2015 4:16 PM

    AMT Import Low Res Proxy

    I'm looking at creating an function with the AMT SDK to import a low-res proxy format into Avid Interplay. I currently am importing XDCAM HD and IMX-30 formats, but I'm not familiar with the low-res proxy. The specs for low-res proxy provided to me are two proxy formats, MPEG-4 at 500 kbps and H.264 at 800 kbps. Both use MXF Op-atom for a container format and MP2 audio at 96kbps per channel.

     

    1st question: How would I create the video essence? I currently use FFMBC to produce the XDCAM HD / MXF formats. There is nothing available to produce an H264 / MXF format as far as I can tell.  Any help would be appreciated.

     

    2nd question: Is there a method to import an Low-res proxy, or a call to the web services that tells Interplay that this is a low res proxy.  And does the low-res proxy have to be linked to the main video by the MOBID, or something?

     

    Thanks,

     

    Joe

  • Fri, Feb 27 2015 7:03 PM In reply to

    • robg
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    Re: AMT Import Low Res Proxy

    Joe,

    1. You can use AMT to create either MPEG-4 or H.264 proxy meda, with MP2 audio in MXF Op-atom format.

    For example, check out these XML files in the AMT SDK:

    /XML/MPEG4_30_500_2A_MPEG2.XML
    /XML/H264_1080i_2997_2A.XML

    Other formats and frame rates are available, too.

    Note that AMT has two different modes, pass-through and transcode. Pass-through is when the media has already been compressed, and it is just passing through AMT. Transcode is when AMT does the compression from uncompressed media.

    2. You can use AMT to create multiple resolution master clips via CreateAmtFile, CreateAmtFileOnSharedStorage or CreateAmtInterplayClip by explicitly creating a clip with the same source MOB ID, starting timecode and duration.

    Hope this helps.

    - Rob

     

  • Fri, Feb 27 2015 7:08 PM In reply to

    • andym
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    Re: AMT Import Low Res Proxy

    Hi joelatakoo,

    The AMT SDK allows you to create an Avid compatible H.264 proxy and that's the only supported way of creating a proxy for Interplay. AMT will create suitable Avid OP-Atom video essence for you. When creating media, AMT allows you to specify a so-called 'source ID', enabling you to create a proxy as an additional resolution for an already existing asset.

     

    Rgds,

    Andy

  • Fri, Feb 27 2015 8:58 PM In reply to

    Re: AMT Import Low Res Proxy

    If pass-through is available, is there a good mechanism for creating the H264 such as FFMPEG with those same specs?

    If not, then I assume the source would have to be an uncompressed file such as RGB (mov. avi)? 

  • Fri, Feb 27 2015 10:25 PM In reply to

    • andym
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    Re: AMT Import Low Res Proxy

    Avid does not recommend or support using AMT passthrough for externally compressed H.264 bitstreams. To minimize compatibility issues, the Avid product portfolio relies on receiving a narrowly defined proxy bitstream as generated generated by AMT and other products for this purpose. AMT is a frame based SDK that supports a wide range of source encodings and is not limited to uncompressed sources.

  • Fri, Feb 27 2015 10:43 PM In reply to

    Re: AMT Import Low Res Proxy

    That's great. We'd rather not have to produce a uncompressed format. Could you give an example of a frame-based source encoding that could work?  Thanks.

  • Mon, Mar 2 2015 4:22 PM In reply to

    • robg
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    Re: AMT Import Low Res Proxy

    Joe,

    There are a couple of samples in the AMT SDK that demonstrate how to do this. Take a look at TestRawToAmt() and/or TestRawToInterplay().

    These functions show how to do frame-based source encoding using AMT.

    - Rob

     

  • Sat, Mar 21 2015 12:35 AM In reply to

    Re: AMT Import Low Res Proxy

    Our attempts have been unsuccessful so far. 

    Here are the steps that one of our team members have tried. 

    steps - 

    1. create a MXF to AMT for the orginal file with the command. The source MXF is XDCAM HD 50 Opatom.

    mxf_to_amt "C:\Users\rajneesh\Desktop\clients\latakoo\avid_low_res\input_file\for_avid\vai_goodbye_NBC_UNC_20150215141007_v1.mxf" "" "C:\Users\rajneesh\Desktop\clients\latakoo\avid_low_res\input_file\for_avid\output" "C:\Users\rajneesh\Desktop\clients\latakoo\avid_low_res\input_file\for_avid\vai_goodbye_NBC_UNC_20150215141007_a1.mxf" "C:\Users\rajneesh\Desktop\clients\latakoo\avid_low_res\input_file\for_avid\vai_goodbye_NBC_UNC_20150215141007_a2.mxf" "C:\Users\rajneesh\Desktop\clients\latakoo\avid_low_res\input_file\for_avid\vai_goodbye_NBC_UNC_20150215141007_a3.mxf" "C:\Users\rajneesh\Desktop\clients\latakoo\avid_low_res\input_file\for_avid\vai_goodbye_NBC_UNC_20150215141007_a4.mxf" "C:\Users\rajneesh\Desktop\clients\latakoo\avid_low_res\input_file\for_avid\vai_goodbye_NBC_UNC_20150215141007_a5.mxf" "C:\Users\rajneesh\Desktop\clients\latakoo\avid_low_res\input_file\for_avid\vai_goodbye_NBC_UNC_20150215141007_a6.mxf" "C:\Users\rajneesh\Desktop\clients\latakoo\avid_low_res\input_file\for_avid\vai_goodbye_NBC_UNC_20150215141007_a7.mxf" "C:\Users\rajneesh\Desktop\clients\latakoo\avid_low_res\input_file\for_avid\vai_goodbye_NBC_UNC_20150215141007_a8.mxf"

    2. run the transcode command to convert to MPEG4

    transcode "C:\Users\rajneesh\Desktop\clients\latakoo\avid_low_res\input_file\for_avid\output" "C:\Users\rajneesh\Desktop\clients\latakoo\avid_low_res\input_file\for_avid\output\output.XML" "C:\Users\rajneesh\Desktop\clients\latakoo\avid_low_res\input_file\for_avid\MPEG4_25_500_8A.XML" "C:\Users\rajneesh\Desktop\clients\latakoo\avid_low_res\input_file\for_avid\output_2"

    3. it fail to transcode with message saying that it is not able to find the codec for transcode.

    4. we are using AMT SDK 2.11

    I've also tried TestRawToAMT() but we've been unable to determine the format for the proper input. I've used Uncompressed RGB video but the AMT clip output produces a green screen. You've mentioned that the input format does not necessarily have to be uncompressed. Could you provide an example of a video/audio that can be used and the best way to transcode to that standard?

     

    thanks,

    Joe

     

  • Wed, Mar 25 2015 1:30 PM In reply to

    • robg
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    Re: AMT Import Low Res Proxy

    joelatakoo,

    We got your test media and we are looking at it now...

    - Rob

     

  • Thu, Mar 26 2015 2:18 PM In reply to

    • robg
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    Re: AMT Import Low Res Proxy

    joelatakoo,

    I was able to compress your media to using the sample app in two steps using the h.264 compressor.

    The first step is to decompress the XDCAM HD:

    AMT_DLL_sample_app.exe transcode
    "C:\low_res_issue\output"
    "C:\low_res_issue\output\output.XML"
    "C:\low_res_issue\UNC_1080i_2997_8A.XML"
    "C:\low_res_issue\output2"

    The second step is to compress to h.264

    AMT_DLL_sample_app.exe transcode
    "C:\low_res_issue\output2"
    "C:\low_res_issue\output2\output2.XML"
    "C:\low_res_issue\H264_1080i_2997_8A.XML"
    "C:\low_res_issue\output3"

    Please give this a try and see if it works for you.

    - Rob

     

  • Fri, Mar 27 2015 3:54 PM In reply to

    Re: AMT Import Low Res Proxy

    Thank you.

     

    Question: What version of the AMT are you using?

  • Tue, Mar 31 2015 5:53 PM In reply to

    Re: AMT Import Low Res Proxy

    Hello. Thanks for the assistance. We are making progress in that your suggestion successfully created the proxy video but the audio track appears to be not playing back correctly once imported into Avid. We are investigating but may have a follow on question if we can't figure it out.  

  • Thu, Jun 18 2015 6:04 PM In reply to

    Re: AMT Import Low Res Proxy

    We've been successful with the method you provided in conducting 2 transcodes to produce the proxy video from a source XDCAM HD 50 clip. A problem has occurred now that the XDCAM HD 50 clip is now using 24 bit audio. Since the H264 Low-res proxy requires 16 bit audio, we have been unable to transcode either the XDCAM to the intermediate Uncompressed format using the 16 bit format since it throws this error:

    ERROR: 'AMT_UNSUPPORTED_TRANSCODING_REQUEST'

    If we use the 24 bit param to transocde to the Uncompressed, the clip is created successfully. But, then trying to transocde the clip to H264 using 16 bit param throws:

    ERROR: 'AMT_MPEG1LAYERII_PCM_QUANTIZATION_NOT_SUPPORTED'

    If we keep the H264 param to 24 bit, the conversion begins but usually freezes around half way through the frames and has to be stopped.

    Would you happen to know if there is something we could do to eleviate the problem.  Thanks. Joe

  • Fri, Jun 19 2015 5:41 PM In reply to

    • robg
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    Re: AMT Import Low Res Proxy

    OK, I'll check with our developer support team. In the meantime, you may be able to use a tool like ffmbc to covert the audio from 24 bit to 16 bit samples.

    The steps would be:

    1. Use AMT to decompress the XDCAM HD

    2. Use ffmbc to convert the audio files to 16 bit

    3. Use AMT to compress to H264

    - Rob

     

  • Fri, Sep 4 2015 8:42 PM In reply to

    Re: AMT Import Low Res Proxy

    Hello.

    We've successfully added the process to convert and import the 16 bit Low-res proxy. A question came from the customer related to Interplay Access and the dynamic relinking. They noticed that the High Res Comes in and the Audio Bit Depth that shows in Avid Access is 24bit but once the Low Res Proxy is processed this changes to 16 bit as it’s the last thing that’s checked in. We checked the High Res in Media Composer and its definitely 24 bit.

    They have spoken with their Avid engineers and they advise having Access showing 16bit Audio may cause the below issue:

     “It may cause issues where the system thinks the correct audio bit rate is not available. This may cause potential dynamic relink problems, I think we would want to recheck-in the high res at the end to make sure it was the last metadata check-in for correct metadata of the clip.”

     Is it possible to re-checkin the Hi Res post the Low Res checkin so that Access shows the Audio Bit Depth of the Hi Res and not the Low Res?

    Thanks, Joe

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