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Rendering to MXF results in mono audio

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Herman Erasmus
Rendering to MXF results in mono audio
on Jul 17, 2015 at 7:37:49 pm

Greetings Video Editing Guru's and Pro's!

I'm stuck. Really I am, cant help myself out of this one, with the little I know about video editing.

The Job:
Edit a simple music video for a friend so its in an HD format.

The contents:
1 Video track
2 Audio tracks in stereo

The mission:
Get it over to HD - 1920*1080 25fps Interlaced 4:2:2 with PCM 8 channel (4 pairs of stereo) audio: 24 bit, 48000 sample rate.

I did what I thought must be done, and it all looks and sounds fine in the preview. However, when I render it out, things go wrong and I end up with monural audio (althoug my audio was indeed stereo).
Played around with the Render As setting: Enable/disable Multichannel Mapping (selected the Master track - and not the mono mixdown)... added busses and selected them, customised the template, nosiree! Mono it stays. Even dropped in another audio track for should it be the audio track that is maybe out of phase, or something. No joy!

Obviously I'm doing something wrong or missing a simple, yet critical step. Any of you pro's care to help out and kick me in the right direction please?

Appreciate!


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Wayne Waag
Re: Rendering to MXF results in mono audio
on Jul 18, 2015 at 1:50:47 am
Last Edited By Wayne Waag on Jul 18, 2015 at 2:50:36 am

Sorry, I'm not a Guru or Pro, but I don't think Vegas will do what you're asking (hope I'm wrong). It sounds as if you want to render to an MXF container that has 1 video stream and 4 audio streams. If that's the case, I suspect that you would have to render an MXF file with one of the audio streams and then render the three remaining audio tracks as three separate WAV files. You would then have to remux these into a single MXF file having the 1 video and 4 audio streams. You can use FFmpeg to do this. I tried it and it does work--1 video and 4 audio streams within a MXF container. As an aside, I tried a straight MXF render with your project settings. It produced a single stereo file that combined the 4 audio tracks. Interestingly enough, MediaInfo showed them as two mono audio tracks, although when imported into Vegas, it was a single stereo track. In any case, FFmpeg will work. If interested, I can help you with the necessary Command line.

wwaag

Added: The resulting file may not work for you. It plays OK in VLC, but will NOT open in Vegas. Regardless, here is the link to the test file so you can try it out. https://www.dropbox.com/s/akc4knw4zz8sgf1/output.mxf?dl=0


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Herman Erasmus
Re: Rendering to MXF results in mono audio
on Jul 18, 2015 at 9:39:21 am

Hi Wayne,

Thanks so much for the responce and going to all the trouble to create that test file, which I'm now downloading. Noticed in VLC your audio is mono as well (nice visuals1)

I followed the steps in John's excellent tutorial, had some underlying issues: installed QuickTime and then the Avid DNxHD codecs. Then things got a bit bitter after configuring the template as he instructs. I actually managed to create a file with stereo audio in it - after trying for who knows how many hours!

However, then I try and modify the audio with Enable Multichannel mapping, it goes to mono audio again.

Can I safely assume, tha whenever you try and do something with audio streams and you are messing about, SVP kind of defaults to Mono audio?

So if I understand you correctly with your suggestion, I need to add the very same audio track (44kHz stereo mp3 file) 4 times into the project, then assign it to Busses A to D, then try and render it again? Customise template, tell it 4 channels, and see what the output brings?

Sorry if I understand wrong or reason way out of line, I'm as inexperienced with SVP as a cockroach in a paint factory!

Also, is it correct that I'm ending up with a file of 2.7gig for a 00:03:05 project? Given the specs that it must be:

File Format: MXF OP1a Codec: DNxHD 8bit 120Mbps
Stored size: 1920*1080 Frame Rate: 25/1
Frame Type: Interlaced/TFF Chroma: 4 2 2
HD Audio: PCM 24bits per sample, 8 channel 48000kHz


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Wayne Waag
Re: Rendering to MXF results in mono audio
on Jul 18, 2015 at 4:07:06 pm

Can I safely assume, that whenever you try and do something with audio streams and you are messing about, SVP kind of defaults to Mono audio?

I suspect that this is indeed the case for MXF. Stereo will render as 2 mono channels (left and right). Thus 4 stereo tracks will render as 8 mono tracks. I redid the little test footage. Here is a screenshot of the timeline.



Here is the link to the re-rendered file, showing the 8 mono tracks and not 4 stereo tracks.

https://www.dropbox.com/s/wqnktoytusg1jsp/mxf%20test%20final.mxf?dl=0

Perhaps someone could confirm that this is indeed the way Vegas works and it is the correct way to proceed. You could use FFmpeg to create the 4 stereo tracks, but from what I now see, I wouldn't recommend it. You might pose your question on the Vegas pro forum. In any case, good luck.

wwaag


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Herman Erasmus
Re: Rendering to MXF results in mono audio
on Jul 18, 2015 at 7:14:56 pm

So to solve my problem, I need to copy the same Stereo Audio track (and not insert it 4 times?), like Wayne has shown here, allocated each to a different Bus, and render it Multichannel Mapping Enabled, to get 4 pairs of stereo in the output file?


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John Rofrano
Re: Rendering to MXF results in mono audio
on Jul 18, 2015 at 6:07:58 pm

[Herman Erasmus] "File Format: MXF OP1a Codec: DNxHD 8bit 120Mbps"
What you created does not match these specs. They are asking for DNxHD in an MXF container and you are placing it in a MOV container. That's not the same thing. Vegas Pro is not capable of placing DNxHD in an MXF container so you cannot create this file with Vegas Pro.

~jr

http://www.johnrofrano.com
http://www.vasst.com



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John Rofrano
Re: Rendering to MXF results in mono audio
on Jul 18, 2015 at 6:12:22 pm

[Herman Erasmus] "Get it over to HD - 1920*1080 25fps Interlaced 4:2:2 with PCM 8 channel (4 pairs of stereo) audio: 24 bit, 48000 sample rate. "
Stereo is concept, not a file format. The file format will always have 2 mono tracks. Whether they are interpreted as Left and Right images from a Stereo recording is up to the software that reads it and maps it as such. That's why Vegas Pro allows you to control the mapping when you read the file back in. If you created a file with 8 channels from your 4 stereo pairs then you've created the audio successfully.

~jr

http://www.johnrofrano.com
http://www.vasst.com



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Wayne Waag
Re: Rendering to MXF results in mono audio
on Jul 18, 2015 at 6:59:57 pm

[John Rofrano] That's why Vegas Pro allows you to control the mapping when you read the file back in.

How do you do this? When I read the file with 8 audio channels that I've created, it only shows a single stereo track with the first 2 channels? How do I get the other 6 channels and do the assignments?

wwaag


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John Rofrano
Re: Rendering to MXF results in mono audio
on Jul 19, 2015 at 12:25:11 am

[Wayne Waag] "How do I get the other 6 channels and do the assignments?"
Two ways:

(1) Copy the audio track 3 more times. Right-click on the 1st copy, select Channels and then Channels 3/4. Right-click on the 2st copy, select Channels and then Channels 5/6. Right-click on the 3st copy, select Channels and then Channels 7/8. You now have 4 tracks with 8 channels mapped to 4 stereo pairs (1/2, 3/4, 5/6, 7/8).

(2) Go to Options | Preferences | General and check Import MXF as multichannel. Now drop the MXF file onto the timeline and you will get 8 mono tracks. Do the same as option (1) and right-click the first 4 audio tracks one by one and select Channels 1/2, 3/4, 5/6, 7/8. Then delete the last 4 audio tracks (they are not needed)

Notice that you can do alternate channel mappings. For example you can map mono channels 2/3 or 4/5 as stereo. So if your first track was mono and your next two were stereo you can leave 1 as mono and make 2/3 stereo. This is why when you send a show off for broadcast they request that the Slate contain the audio channel mappings so that they know how interpret them correctly.

~jr

http://www.johnrofrano.com
http://www.vasst.com



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Wayne Waag
Re: Rendering to MXF results in mono audio
on Jul 19, 2015 at 3:09:15 am

[John Rofrano]

Thanks so much for your detailed explanation. One thing I really enjoy about Vegas, like Photoshop, is that there is always so much more to learn, lots of new tricks, even for us old otters. You should be commended for the time you spend to give help and also your patience when so many others (including me) would simply say RTFM. Again, thanks.

wwaag


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Wayne Waag
Re: Rendering to MXF results in mono audio
on Jul 19, 2015 at 3:12:23 am

[John Rofrano]

Thanks so much for your detailed explanation. One thing I really enjoy about Vegas, like Photoshop, is that there is always so much more to learn, lots of new tricks, even for us old otters. You should be commended for the time you spend to give help and also your patience when so many others (including me)would simply say Read The blank Manual. Again, thanks.

wwaag


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John Rofrano
Re: Rendering to MXF results in mono audio
on Jul 19, 2015 at 4:31:44 pm

Thanks Wayne. I appreciate the kind words. When I find a manual that's worth reading, I'll start directing people to it. lol :-D

~jr

http://www.johnrofrano.com
http://www.vasst.com



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Wayne Waag
Re: Rendering to MXF results in mono audio
on Jul 19, 2015 at 5:43:15 pm

[John Rofrano]

When I find a manual that's worth reading, I'll start directing people to it.

Well, why don't you write one? Seriously. Given the seemingly shrinking base of Vegas users, it probably wouldn't be a very successful commercial undertaking, but it might be fun. Just a thought.

wwaag


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John Rofrano
Re: Rendering to MXF results in mono audio
on Jul 20, 2015 at 3:41:00 pm

[Wayne Waag] "Well, why don't you write one? Seriously. Given the seemingly shrinking base of Vegas users, it probably wouldn't be a very successful commercial undertaking, but it might be fun. Just a thought."
We (VASST) did! It's called Vegas Pro 11 Editing Workshop and was written by my good friend Douglas Spotted Eagle. :-D

I co-wrote Instant ACID for Sony ACID Pro so I know how much work goes into writing a book.

I aslo helped Spot write a few chapters of Instant Vegas Movie Studio.

So while you meant it jokingly, I've published books on the topic and I'd like to think that the book is better than the manual.

~jr

http://www.johnrofrano.com
http://www.vasst.com



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Herman Erasmus
Re: Rendering to MXF results in mono audio
on Jul 18, 2015 at 7:02:14 pm
Last Edited By Herman Erasmus on Jul 18, 2015 at 7:04:06 pm

I do appreciate the advise and help from the fellow forumites.

John, so I'm basically placing a DNxHD into a MOV container (my last try) and not into a MXF container, if I'm grasping the concept now. How would you reckon do I go about getting this done? I see under Output Format I have options of:
- Panasonic P2 MXF
- Sony MXF
- Sony MXF HDCAM SR

Will there be a preset in there that will work, or do I adopt from your tutotial and create a custom template under one of those MXF options?

Thanks!


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John Rofrano
Re: Rendering to MXF results in mono audio
on Jul 19, 2015 at 12:45:36 am

[Herman Erasmus] "Will there be a preset in there that will work, or do I adopt from your tutotial and create a custom template under one of those MXF options? "
I'm not sure if you read my other post but Vegas Pro cannot produce an MXF file with the DNxHD codec in it. It simply can't be done with Vegas Pro.

I believe that Adobe Premiere Pro can create files using the Avid DNxHD codec in an MXF OP1a container.

~jr

http://www.johnrofrano.com
http://www.vasst.com



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Herman Erasmus
Re: Rendering to MXF results in mono audio
on Jul 19, 2015 at 7:48:06 pm
Last Edited By Herman Erasmus on Jul 19, 2015 at 8:03:54 pm

A big word of THANKS to Wayne and John for the help, pointers and tips they offered!

Based upon what was said, on the limitations of SVP, I installed the trial version of Première Pro and did the project in there. Had disturbing images that it might be as complicated as PhotoShop and that again I will revert to being a cockroach in a paint factory, but alas not! When I went to Export - Media I found the correct container and codecs already present. Afraid to bork up, I rendered it with the default settings and the output sounds perfect stereo. In VLC it looks like:



Seems to be the specs it should be? Only snag, is audio is 16 bits and not the prescribed 24.

Rendered it then as 8track audio:



Seems to be fine in terms of the video requirements (John please check me on that!) but I changed the audio to the other available option, being 32 bit. Unless the Codec information: PCM S24 LE denotes the actual 24bit nature and not what VLC reports as Bits per sample: 32. The previous render gave audio as PCM S16 LE.

Again, my deepest thanks to the forum and guidance I was able to get from you guys. You video chaps are by far the friendliest lot I encountered on a forum for a very long time! :-)


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John Rofrano
Re: Rendering to MXF results in mono audio
on Jul 19, 2015 at 11:12:48 pm

It looks right from the images. The 24 vs 32 bit seems odd but I agree that maybe VLC misinterpreted it. I'm glad that worked for you. Too bad it couldn't be done with Vegas Pro. :(

~jr

http://www.johnrofrano.com
http://www.vasst.com



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Herman Erasmus
Re: Rendering to MXF results in mono audio
on Jul 21, 2015 at 9:07:28 am

The final product that I supplied to the broadcaster can be found on this link.
If maybe Wayne and John could (when they do have some time) just technically inspect what I did in terms of containers and codecs and formats, and give a verdict if I stayed on the right path or ended up in die mud.

The video track I did not do much with, just used what I was given. Audio was given a bot of enhancement.

https://www.dropbox.com/sh/p6fmitbels7w1sz/AACXXjhXMnzLJ1Zo8GDXHEa0a?dl=0

Just got the email back from the technical guys. *sigh* Thought I cracked it first time with your help, but seemingly I fluffed! The container and format is perfect, but ....
EBU R128 compliance: Audio on tpmax of -3.0dB and LUFS -23lufs.
What on earth?! Goooooooogle here I come!


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John Rofrano
Re: Rendering to MXF results in mono audio
on Jul 21, 2015 at 11:53:20 am

[Herman Erasmus] "The container and format is perfect, but ....EBU R128 compliance: Audio on tpmax of -3.0dB and LUFS -23lufs. What on earth?! Goooooooogle here I come!"
Congratulations on getting the container correct!

No need to Google at all. Most of us work in Broadcast. What do you need to know? Was tpmax of -3.0dB and LUFS -23lufs the target you need to hit? or the current measurement?

Do you understand what they want? I don't want to explain what you already know.

Do you have Vegas Pro 13.0 because you are going to need Loudness meters and only Vegas Pro 13.0 has them.

Let us know what you need and we'll help you out.

~jr

http://www.johnrofrano.com
http://www.vasst.com



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Herman Erasmus
Re: Rendering to MXF results in mono audio
on Jul 21, 2015 at 12:13:32 pm

Thanks for the reply John. Cant all the forums have such nice people like you guys?!

What they want: audio to conform to the (nearly) universal broadcast standard of -23dB average. What I did wrong: I adjusted audio levels to be under -3dB on the meters and foolishly ignored the rest of it (thought only the max volume is important), so it bounced back to me.

Found a super nice youtube video explaining it... In Audition there is: Window - Match Volume. Set it to ITU-R BS.1770-2 Loudness and a level of -23dB. It showed it had:
ITU Loudness: -11LUFS
Total RMS: -13dB
Peak: -1.92dB. Screamingly loud, in your standards?

Ran it and the levels dropped to:
ITU Loudness: -23LUFS
Total RMS: -25.4dB
Peak: -13.6dB

Hope I nailed it this time! TPMax of -3 I dont think I hit, seems to be -13 now. Guess the way the original audio was mastered by the recording studio, influences this max?

Will still go and check the loudness meters in SVP.

Again, appreciate your help and pointers and advise and wisdom!


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John Rofrano
Re: Rendering to MXF results in mono audio
on Jul 21, 2015 at 12:24:53 pm

Yea, Audition Match Volume makes it all too easy. ;-) Didn't realize you had Audition. Way easier than using Vegas Pro for that particular job. I guess you're all set. Good luck!

~jr

http://www.johnrofrano.com
http://www.vasst.com



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Herman Erasmus
Re: Rendering to MXF results in mono audio
on Jul 21, 2015 at 12:33:45 pm

All set yes, thanks to you and Wayne helping me in the right direction!

Will hear either tonight or tomorrow from the Broadcaster if its up to standard now.


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Aaron Star
Re: Rendering to MXF results in mono audio
on Jul 19, 2015 at 5:53:09 pm

Avid would be your best tool to work in DNxHD.mxf.

In Vegas, HDCAM SR Lite would be your comparable MXF format with 12 channels of audio. Most other NLEs will support HDCAM and XDCAM with additional sony plugins added, some will support without plugins.


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