DNxHD Encoder fails when Avid Structure is selected

[joshc011]

Hello,
I'm trying to use FFAStrans to make proxy files for an avid project. It appears others have done this successfully, but when I click the "Create Avid project structure" box, the transcode fails within a few seconds of the job starting. If I don't select Avid Structure, the file transcodes perfectly, but I really need OP-Atom for the Avid machine.
Thanks,
JC

[emcodem]

Hey JC,
welcome to the forum and thank you for using FFAStrans!

Not yet done but first insight: it's about the 1080p2398 framerate you are encoding to.

BMX Error:

Code: Select all

(2022-07-28 06:13:19) ERROR: 'sample_rate == FRAME_RATE_23976 || sample_rate == FRAME_RATE_24 || sample_rate == FRAME_RATE_25 || sample_rate == FRAME_RATE_2997 || sample_rate == FRAME_RATE_30 || sample_rate == FRAME_RATE_50 || sample_rate == FRAME_RATE_5994 || sample_rate == FRAME_RATE_60 || (IsSound() && sample_rate == SAMPLING_RATE_48K)' check failed
(2022-07-28 06:13:19) ERROR:     near ../../../src/mxf_helper/MXFDescriptorHelper.cpp:140
(2022-07-28 06:13:19) ERROR: BMX exception caught: 'sample_rate == FRAME_RATE_23976 || sample_rate == FRAME_RATE_24 || sample_rate == FRAME_RATE_25 || sample_rate == FRAME_RATE_2997 || sample_rate == FRAME_RATE_30 || sample_rate == FRAME_RATE_50 || sample_rate == FRAME_RATE_5994 || sample_rate == FRAME_RATE_60 || (IsSound() && sample_rate == SAMPLING_RATE_48K)' check failed

The reason seems to be on a quick peek that ffmpeg writes samplerate and editrate metadata 2997/125 into the mxf container.
When i replace all occurences of 2997/125 by 24000/1001 bmx is able to transwrap the video (replace hex values in a locally transcoded ffmpeg op1a version).

Now we need to find out how to tell ffmpeg to write the correct video sample rate into the mxf container.

stay tuned...

[admin]

Hi,

It's a matter of specifying 24000/1001 instead of 23.98 in ffmpeg. So consider it a bug that's fixed for the next release.
Thanks for notifying!

-steinar

[joshc011]

OK thanks for the quick replies everyone.
FYI I did notice potentially the same issue with 23.98 and DNxHR when selectin MXF(BMX)