iMovie HD 6 - Audio Getting Stripped Out on Export

[bittersweet]

I'm using imovie HD6 and for capturing and editing my hv20 video and I'm experiencing some very weird audio issues when exporting from iMovie to Quicktime (.mov) or mp4. We recorded some segments of video/audio using a an Azden wireless handheld mic (10HT) and wireless receiver (Azden 100UPR). Other segments of my video were recorded using a hotshoe mounted Rode Videomic on the camera.

Now all the segments of my videos using the Rode Videomic are fine. They export from imovie just fine. All of the segments shot using the Azden handheld mic and receiver loose their audio when I export from iMovie and specify a mono audio setting. In the iMovie, I lay down an extra music track so I have the video's audio track and a 2nd music track.

You can see the video I'm referring to at http://www.youtube.com/watch?v=M3AfhgfBOTw. At about 32 seconds into the video you'll see the audio disappears.

If I export the iMovie to quicktime using full or high quality settings as stereo, the audio in the video is just fine, that is I can hear the audio throughout the whole video. If I then try to export the video to YouTube, YouTube then does something with the video so the audio goes away for some sections that used the handheld mic. I assume YouTube is converting the audio in the video to mp3 mono and that's removing the sound or lowering the audio levels so low that you can't really hear the sections recorded with the Azden handheld.

I've extracted the audio from iMovie and looked at the settings. All sections of the audio, those recorded with the Rode Videomic and Azden handheld are the same - Aiff audio file, 1536 kbps, 48.000 kHz, and 16 bit.

I'm at a lost here and have tried everything I can think off in trying to identify a fix for the issue including trying to convert the audio from 16 bit to 12 bit and from 48,000 to 41,000.

Thanks.

[MacGB]

So you do have audio when in iMovie,

what happens if you export stereo i.s.o mono ? (There may be a difference the way Rode and Azden is handeling the mono/stereo differently)

MacGB

[bittersweet]

So you do have audio when in iMovie,

what happens if you export stereo i.s.o mono ? (There may be a difference the way Rode and Azden is handeling the mono/stereo differently)

MacGB

Wow... Thanks MacGB for answering me. It's been tough getting help on any forums, so thanks so much.

Yes, I get sound in iMovie just fine. And I was getting sound when it was recording in that I was monitoring my levels on the HV20. The audio from the Rode VideoMic and Azden wireless handheld do sound different in iMovie HD 6 in that the Azden handheld stuff sounds better in that a lot of the room noise is not present as it is with the Rode Videomic when played back in iMovie.

Not sure what you mean by exporting as "stereo i.s.o mono" I.m able to export to stereo just fine, but I think YouTube is stripping the audio down to mono and its getting lost on those parts recorded with the Azden Handheld

Here is how I've tried exporting.

Compress using expert Settings:
Movie to Quicktime movie (.mov) as well as tried to go to mp4. Video using h.264

Under Sound settings I've tried exporting under AAC and Apple Loseless (as well as other settings) as Mono. Under Stereo the sound is fine, but the Azden handheld stuff is getting stripped out under mono settings.

Under rate, I've tried both 48,000 and 44.1. Under the render settings I've tried Better and Best Quality settings

Under Encoding Strategy I've tried Average Bit Rate and bit rate settings randing from 64bit, 128bit... all the way up to 256 kbps.

Again you can see the video I uploaded to YouTube where the Azden handheld audio disappears at around the 32 second mark onward - http://www.youtube.com/watch?v=M3AfhgfBOTw

Thanks for your help!

[MacGB]

Glad to help you out (not sure if we will succeed)

This really is a strange problem. What I suspect is that the Azden in fact is recording in mono to just one track. The Rode (I know) is recording mono into two tracks (quasi stereo). So in exporting I gues the empty track (I don't know wether this would be the left or right track from a "normal" stereo track) is taken into the conversion by Youtube.

What I would suggest:
in the export settings for sound you have a choice for the channel "mono or stereo"

try experimenting to set this to stereo, or if that doesn't work to set it to mono and see what happens.

it would be interesting to see if you export just the audio and open that in f.e. Garageband if you get a mono or stereo track.

I have a hunch that here lies the rootcourse of the problem.

Note:
a. I haven't been uploading to Youtube yet, so I am not aware of the precise settings they require as an input
b. neither did I record mono via mono-jacket into the HV20. I have been using Rode (mono) with a stereo jacket and a lavelier mic from Vivanco (stereo/mono) with a stereo-jacket

HtH
MacGB

[ThomaSeidler]

i know you may not like the sound of this but maybe you need something like Final Cut Express HD 3.5 I reckon. or maybe 3 would do: http://cgi.ebay.co.uk/FINAL-CUT-EXPRESS-HD-3-SEALED-UNREGISTERED-COA-ENGLISH_W0QQitemZ260196075052QQihZ016QQcategoryZ18 9QQssPageNameZWDVWQQrdZ1QQcmdZViewItem#ebayphotoho sting

pretty cheap. i certainly found it useful when dealing with my mono signal from ATR35S mic. But that may not be your problem...? You heard stereo signal thru earphones when recording?

Mmm... it could be your video settings, i found youtube freaked out when i sent it h264 files, i got grey screens for first while, and so on. The best files i've found it converts the quickest are h264 - but check my stuff on Youtube settings here (http://harmlesswise.com/0710-youtube-google-video-recording-hdv-avchd#3.1) (probably won't help, but just in case).

Anyway, all the best...

t

[bittersweet]

Update: What I found out was the stuff recorded with the Azden wireless handheld and receiver into the HVZ20 was recorded in stereo, recorded out of phase. The waveform on one track peaked out at the top of the wave form and the other track peaked out the opposite at the bottom of the wave form.

So when I compressed the video to mono or tried uploading to YouTube the two tracks were canceling each other out. So I extracted the audio in Audacity, deleted one of the tracks, copied the top track to another track and set one of the tracks to left channel and the other to right channel and then combined the tracks into a single stereo track. I then replaced the extracted audio track and that fixed the problem.

A real pain, but at least its a solution. I'm going to look at the cable connection going into the HV20 to see if simply adding a mono "jacket" might fix the problem.


i know you may not like the sound of this but maybe you need something like Final Cut Express HD 3.5 I reckon. or maybe 3 would do: http://cgi.ebay.co.uk/FINAL-CUT-EXPRESS-HD-3-SEALED-UNREGISTERED-COA-ENGLISH_W0QQitemZ260196075052QQihZ016QQcategoryZ18 9QQssPageNameZWDVWQQrdZ1QQcmdZViewItem#ebayphotoho sting


I agree, I'm considering going the route of FCE, but I'm new to video and need to train students on an easy to learn platform, thus the reason I'm using iMovie HD 6.




pretty cheap. i certainly found it useful when dealing with my mono signal from ATR35S mic. But that may not be your problem...? You heard stereo signal thru earphones when recording?

Yes I believe I was hearing stereo through the headphones.



Mmm... it could be your video settings, i found youtube freaked out when i sent it h264 files, i got grey screens for first while, and so on. The best files i've found it converts the quickest are h264 - but check my stuff on Youtube settings here (http://harmlesswise.com/0710-youtube-google-video-recording-hdv-avchd#3.1) (probably won't help, but just in case)..

I think the issue is the audio being recorded out of phase and not the settings. It didn't matter what my output settings were, when I converted to mono or if YouTube did this, the two stereo tracks canceled each other out. But I really appreciate you providing your video output settings. I bookmarked them and will definitely give them a try to see how they work for me. The quality of your videos on YouTube are great.

Thanks so much!