Export .MXF with stereo (dual channel) audio track

Hello

For a broadcaster, I'm trying to deliver an MXF OP1a 1080i25 file, with video in AVC-Intra 100 (no problems here) and two stereo audio tracks (from two different stereo audio mix, French version and International version).
I must specifically output each one of those two stereo mix on one dual-channels tracks, so I must have two dual-channel (stereo) tracks, and not 4 single (mono) tracks.

Using Resolve 14, here is what I did :
1/ the source audio mix are stereo .WAV files, properly defined as such in the Clip Attributes of the Media Pool
2/ the timeline tracks are stereo (2.0) tracks, the WAV files do playback properly in stereo
3/ in Fairlight, I create two stereo main buses, and I assign track 1 to bus 1, and track 2 to bus 2. The Mixer then properly displays two stereo master buses, on each the two stereo audio files play properly : the first audio stereo source file on the first main stereo bus, the second audio stereo source file on the second stereo main bus.
So far, so good.

But when delivering in .MXF, no matter what audio setup I select (either the two stereo Main Fairlight buses output, or the stereo timeline tracks output), the audio in the resulting MXF are always flagged (in Media Info, for example, and by the broadcaster's QC tool) as 4 single mono channel tracks.

The same audio setup output in Quicktime .MOV does work : I do get two dual-channel stereo tracks.
But not in .MXF.

Has anyone ever managed to output stereo dual-channel tracks in an MXF from Resolve ? If so, what do I do wrong ?

Thanks !


Guillaume

[Shrinivas Ramani]

Could you try with 15.0 beta 6 please and let us know if the issue persists?

It has some related audio bug fixes.

Thanks

Hello

Thanks for the reply, I just downloaded and installed the 15b6 version, but I still get two mono channelled-tracks in the resulting MXF file.


Here is my audio setup inside of Resolve, the Fairlight Bus Format is just one main stereo (the default one) :

Resolve_Fairlight_Audio_bus_format.png (33.56 KiB) Viewed 7059 times

Fairlight bus assign is also pretty straightforward :

Resolve_Fairlight_Audio_bus_assign.png (37.13 KiB) Viewed 7059 times

On the Deliver page, I chose the MXF flavor that I need (AVC-Intra 100, 1080i25) :

Resolve_Video_Deliver.png (73.01 KiB) Viewed 7059 times

[Shrinivas Ramani]

I assume the audio tab for your render job just uses the default main bus? With render 1 track per channel turned off?

Could you DM me a link of your project export (just the drp file without media)?

Thanks

Obviously, I pick the main Fairlight stereo bus as audio output :

Resolve_Audio_Deliver.png (64.68 KiB) Viewed 7051 times

But after deliver, in the Media Info of the resulting MXF, I still get two tracks, each one containing one channel :

MediaInfo_result.png (118.89 KiB) Viewed 7051 times

What I do need, from the sample provided file, is this :

MXF_stereo_OK_what_I_want_CROP.png (174.67 KiB) Viewed 7050 times

One track containing two channels.

I assume the audio tab for your render job just uses the default main bus? With render 1 track per channel turned off?

Yes I pick the stereo main bus as output, and the "Render one track per channel" is not ticked.

Could you DM me a link of your project export (just the drp file without media)?

I think I did, let me know if you can open the DRP ?

In the meantime, I found a workaround with FFMPEG :

1/ I export from Resolve the video silent (without audio) as an .MXF OP1a AVC-Intra 100 1080i25 (every flavor I need)

2/ I export from Resolve the audio as stereo .WAV (48 Khz 24 bits)

3/ I rewrap without converting/re-compressing via FFMPEG :

Code: Select all

ffmpeg -i VideoSilentFile.MXF -i AudioStereoWaveFile.wav -map 0:0 -map 1:a -vcodec copy -acodec copy VideoWithStereoAudio.MXF

And voilà : an .MXF file with only one stereo audio track containing two audio channels

[Shrinivas Ramani]

This problem seems to be specific to certain MXF OP1a variants. We're looking into it.

Thanks for your report.

I think I managed to narrow it down to the use of the MXF writing library "Sony MXF Development kit", see screenshots below : I can output stereo tracks in MXF when using XDCAM or DNxHD codec, but not MPEG4 (Sony).

DNxHR_HQ__Output_main_stereo_bus.png (80.6 KiB) Viewed 6937 times

XDCAM__Output_main_stereo_bus.png (83.01 KiB) Viewed 6937 times

MPEG4-422__Output_main_stereo_bus.png (83.3 KiB) Viewed 6937 times

By the way, I opened a Blackmagic support ticket : Support #LFK-129-48639 , so no need to double-investigate on your side

Regards,

Guillaume

I can see that this is an old thread - but I am dealing with the same problem. I need to deliver an MXF with embedded audio. Is there any way to do it and what would be the settings?

Thank you very much.

I can see that this is an old thread - but I am dealing with the same problem. I need to deliver an MXF with embedded audio. Is there any way to do it and what would be the settings?

Thank you very much.

Same here, I need to export XDCAM MXF with embedded audio tracks, but I can only get it to export one video file and four individual audio mxf files to the folder. I need to make it one MXF file with embedded audio. Anyone know if this is possible?

Sounds like the difference between OP1a and op atom.


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