Roles, multitrack quicktime files and H.264

When I 'Share' a single multitrack quicktime file, with all my roles selected, to Prores all the audio roles are audible in the exported output file. However, when I export the same to an H.264 file some roles are not audible. I've tested this and it's not predictable in terms of what audio roles make it to the output and which don't. I've also tried converting the multitrack Prores quicktime into H.264 using Handbrake/ffMpeg etc and problem is same.

I'm assuming the H.264 format can't cope with more than 2 audio channels so can't cope with a multitrack quicktime (checking the file with iMediaHUD the original Prores output is showing Audio #1, #2 and #3) so maybe this is an oversight by the FCPX code writers. Or is there a workaround anyone has discovered?

Of course when I simply 'share' 'audio and video' to H.264 all audio tracks are heard so this leads me to think the issue is that H.264 can't deal with more than 2 audio channels that a multitrack quicktime file creates.

Any insights or help warmly welcomed as I'm having to do two round trips per export at the moment. The first to multitrack proress and then that output reimported for a simple 'video and audio' H.264 export.

Thank you. Paul

H.264 only support 2 channels, correct. If you want all your roles as separate channels, use ProRes. It'll maintain the quality of both audio and video much better for whatever app you're going out to.

And what do you mean by "all my roles selected"? How specifically are you arranging the audio stems in the export (Share) window?

Thanks Ben

That's as I thought but doesn't that mean that basically I can't get a youtube/vimeo uploadable H.264/Mpeg4 output file when using the 'output as quicktime multitrack' in export roles without doing two outputs? If so that kind of sucks. (compressing the multitrack prores with an external compressor yields same audio drop out results).

I have a dialogue/effect/music roles setup but in my testing I made just one audio role for all audio and still got the problem I described of some audio not being audible. When the audio drops out it is clearly one clip here and there but not predictable.

What is the purpose of doing a multichannel H.264 for YouTube? What is your purpose in messing with Roles in the first place? That is only for more complex output to other applications.

Screw Roles and Stems for YouTube output. Just do a normal H.264 for YouTube, it'll be fine.

So my big question is, what are you trying to achieve "specifically" with Roles for YouTube? YouTube doesn't even support multiple audio channels besides stereo pairs.

Hi Ben

I 'mess' with roles because they help me enormously. I'm working with multiple language versions of one film so I create a role for language A subtitles and language B subtitles and same for language A dialogue etc etc. This means I can work in one project timeline with multiple language versions by selecting /deselecting roles. This is a game changer and since 10.0.3 lots of people have been very thankful for the roles functionality.

You're absolutely right, I don't want a multitrack version for youtube - that's my problem - FCPX won't let me create a simple dual channel prores quicktime from the roles 'share' function to compress down to H.264. I'm simply asking if someone has found a workaround to avoid double outputting as I have to do now so my clients can view versions on youtube/vimeo.

Many thanks, Paul

I'll have to look at that, but when I've exported as ProRes files, I've been able to specify my title sub roles, and leave all the audio alone. But it's not something I've done in awhile. I'll have to look at that again in the morning.