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I-Frame only on XDCAMHD

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James Ronan
I-Frame only on XDCAMHD
on Sep 12, 2017 at 4:07:33 pm

Hey guys

Hoping I'm posting in the right forum...

I'm trying to export an advert for UK TV.

They're specifications are:

Codec: MPEG-2
Container: OP1a
Profile / Level: MPEG-2 4:2:2 / High
Video: 100Mb/s
Audio: PCM 2ch 48kHz 24bit
GOP Structure: I Frame only
Upper Field First
Chroma: 422
Framerate: 25fps
Dimensions: 1920x1080px
File Extension: .mxf

I am using the XDCAMHD50 PAL (4:2:2) which I think is right, but when supplied it failed because it was "long-GOP" and it needs to be "I-Frame"

In this Codecs settings in Adobe Media Encoder under Advanced XDCAM Settings there are two check boxes:

Force Fixed-length GOPs
Force Closed GOPs

Does anyone would know if having any of these checked would turn it to "I-Frame"
And could anyone explain what they mean?

Thanks a lot!


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Chris Wright
Re: I-Frame only on XDCAMHD
on Sep 13, 2017 at 7:26:17 am

gop length is from I frame to I frame so if that is 1. it should be all i frames (fastest editing)
closed is not using adjacent b frames.(somewhat fast editing)

i would select both and then test with ffmpeg's ffprobe

ffprobe -show_frames videofilename.mp4 > outputfile.txt
Then you just look for the pict_type entries, which will be either I, P, or B. B denotes a b-frame.

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Pradip Patil
Re: I-Frame only on XDCAMHD
on Jan 18, 2020 at 2:52:48 pm

Hi James,

Did you find solution to this as I have received similar specs for a project. I tried what Chris Wright suggested but the file still shows as non I-frame in MediaInfo.


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