Can't convert Final Cut XML to AAF

Dear Fred,

I think we have now finally got to the bottom of this, in your original file there were two stereo tracks (4 channels in total). This was comprised of one AAC stereo pair, and one Dolby AC-3 stereo pair.

FCP X will read the AC-3 correctly but QuickTime cannot as it does not have the appropriate Dolby licence. I think we can agree that we can look at handling the failure with a more appropriate error message, but fundamentally you cannot work with the AC-3 and QT. So I think the only option is to convert any AC-3 into something else which we and QT can work with ie. AAC.

Yours Sincerely

James.

Dear Fred,

Just a quick update we cannot see a way to resolve this in the code with the current QT SDK, realistically I don't think we can progress until we do get a new SDK. Once we do, we will look again and keep you updated.

Yours Sincerely

Yes of course! It was a very exceptional way to get medias and the workaround works fine. I will know for next time...

Hi Fred,

We have been looking at this but I have to caution we are not sure how we can get round the issue as we are fundamentally dealing with the QT SDK, we will keep looking but I would be grateful if you could advise whether the workaround is acceptable for you to use in the long term as we may not be able to resolve.

Yours Sincerely

Fred,

We've figured out what is happening:
The clips that cause the problem have 2 stereo pairs of audio, which is four tracks in total. One of the stereo pairs is MPEG encoded audio, and one of them is AC3 encoded audio. It's strange to have a mix like this in a single file, but it's probably valid.

If I open the clips in FCP 7 or FCP X, it shows 4 audio channels, but if I open the file in QuickTime Player 7 or X, it only shows 2. This is because QuickTime is not licenced for the AC3 audio codec (but FCP is).

X2Pro uses QTKit to extract audio from files (except R3D files where is uses the RED SDK) before it puts the audio in an AAF, but because QTKit has the same codecs as QuickTime, it is not able to extract AC3 audio.

A workaround to this issue (until we have found a better solution) would be to re-encode the audio for any clips like this to not use AC3 and use that in your project instead, but of course you already figured this out by yourself.

I have put in a feature request to ignore AC3 audio tracks and put a warning in the conversion report.

I hope that helps explain it, and I apologise that we aren't able to offer you a better solution at this time.

Nice!

Yes I have downloaded the files with an extension called FVD Video Downloader on Google Chrome. I guess it will take the original media file extension.

FYI I had tried to convert the videos using Handbrake but it did not work. I then put the videos in FCPX and optimized them. The resulting .mov was 10 to 50 times larger but eventually it did work when I completely replaced the clips in the project (because for some reason the m4v version will be used for the export even though there is a .mov optimized version linked in the event; so I had to delete the original clip and import the .mov version as the new original file).

Thanks Graeme

Fred,

Thank you for providing those files, I can reproduce the issue here now so I've passed it on to the development team. I'll keep you updated with any progress.

You said earlier that "Those clips are extracts from archived web streams", but how exactly did you save the web stream to an m4v, or were they already m4vs that you just downloaded?

Sorry I had missed it, I can't find the setting to trigger an email when receiving a private message.

The access is working fine and I am uploading the files right now. Should take less than an hour.

Fred,

I sent you another PM yesterday. Did you get it?

Fred,

I just sent you a new PM with a password which should work this time.

Fred,

I've sent you a private message with FTP details.

Hello Graeme,

Thanks for your feedback.

Those clips are extracts from archived web streams. I can definitely send you the culprits!
Give me the ftp details and I will upload the clips.

Fred,

The error you are seeing "Wrong number of data buffers (2) passed to Add Sample Data (expected 4)" is caused by the FCPXML describing a clip as having 4 audio channels, but the clip (apparently) only having 2.

In the FCPXML there is a line like this:which describes the clip as having 2 audioSources with 2 audioChannels. 2x2=4 audio channels in total.

Can you tell me anything about this clip, like how many audio channels it has, and whether they are stereo/mono/etc what what it was shot on, how it was imported, etc?

Would you be able to provide the clip (/Volumes/d2_USB3_2To/Final Cut Events/BMW Future Retail Event/Original Media/Dépôt de bilan mercredi probablement pour Virgin [H.264 240p~360p] universal.m4v) for me to look at if I gave you FTP details in a private message?

Hi Fred,

In answer to your question "what is the use of the option under Media Handling that lets me think that the AAF file will be created even if there are error messages?": I assume you're talking about the "Handling media that can't be referenced" settings. The "help" section explains it like this:

Reference multi-channel WAV files
Only select this option if you know that your DAW can accept multi-channel WAV files referenced from an AAF file. Pro Tools, for example, cannot handle referenced multi-channel WAV files.
Handling media that can't be referenced
You can choose whether to embed media that cannot be referenced, or generate an error and not create an AAF file. If you do not want any media to be embedded, choose Generate an error, transcode any media which generates an error, then try the conversion again.
If you choose to embed media that cannot be referenced then that media will be subject to the trimming settings.

Tested the export by replacing the original file with the optimized media from FCPX and it's working fine... So apparently it has something to do with the file format or the codec?