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MPEG2 codec in AMT (XDCAM HD 1080 50i)

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Hello

The Mpeg2 codec in AMT assumes some defaults that are wrong.

Using the source XML shipped with AMT toolkit (v. 2.12.9.973)

<AmtMediaAttributes><format><mediaFormat>Uncompressed</mediaFormat><signalStandard>SS_274M_I</signalStandard><colorSpace>CS_YCbCr_709</colorSpace><colorComponentOrder>CCO_CbYCrY_NoA</colorComponentOrder><chromaSubSampling>CSS_4220</chromaSubSampling><resolution>RS_FULL</resolution><componentDataFormat>CT_UCHAR</componentDataFormat><crtRange>CRT_VideoRange</crtRange><bufferFieldOrder>BFO_Merged_F1_First</bufferFieldOrder><bufferLineOrientation>BLO_Top_Bot</bufferLineOrientation><rasterGeometry>RGT_SignalStandard</rasterGeometry><isAlphaPresent>kAVXFalse</isAlphaPresent><alignment>16</alignment><isAlpha0Transparent>kAVXBool_Max</isAlpha0Transparent></format><timecode>00:00:00:00</timecode><bitRateMode>CONSTANT BIT RATE</bitRateMode><framesPerSecond>50</framesPerSecond><storedHeight>540</storedHeight><storedWidth>1920</storedWidth><audioTracks>2</audioTracks><audioBits>16</audioBits><audioBitRate>48000</audioBitRate><audioCompressionType>Avid::WAVE::Uncompressed</audioCompressionType><extendedAttributes><attribute1>This is an attribute (#1)</attribute1><attribute2>This is another attribute (#2)</attribute2></extendedAttributes></AmtMediaAttributes>

Destination XML:

<AmtMediaAttributes><format><mediaFormat>Compressed</mediaFormat><signalStandard>SS_274M_I</signalStandard><dropFrame>kAVXFalse</dropFrame><compressionType>XDCAM-HD 50mbps 1080i 50</compressionType></format><timecode>00:00:00:00</timecode><bitRateMode>CONSTANT BIT RATE</bitRateMode><framesPerSecond>25</framesPerSecond><storedHeight>540</storedHeight><storedWidth>1920</storedWidth><audioTracks>2</audioTracks><audioBits>16</audioBits><audioBitRate>48000</audioBitRate><audioCompressionType>Avid::WAVE::Uncompressed</audioCompressionType><extendedAttributes></extendedAttributes></AmtMediaAttributes>

 

If I examine the resulting Mpeg2 stream I can see that in the picture coding extensions:

top_field is set to 0 (false)

furthermore alternate_scan is set to 0 which means that the standard zig-zag scanning will be used. From what I know interlaced material should always use the alternate scan pattern should be used. I examined the AMT.xsd to see if I can somehow influence these "assumptions" but I can't see anything obvious.

Jaka


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