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paradox on video’s audio when played on desktop vs mobile
https://www.youtube.com/watch?v=8SAI5GNw-2A
this was a recruitment video i made.
What makes me pull my hair out is the paradox…The boss’s voice plays just fine on desktops and laptops. yet TRY the same video on any mobile phone, and you can’t hear his voice at all, yet the other volunteers CAN be heard.
What is going on here?
Well, i did have to lip-sync a separate audio track over his mouth because the original recording got ruined by wind noise. Is that it? Please help me here.
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10 Replies
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Use mono. I assume that you are referring to the voice at :20, which is stereo. Somewhere in the workflow, one of the channels may be flipped, cancelling the other out when the decode in the mobile phone is converting the stereo to mono.
Rule of thumb, unless otherwise absolutely necessary, play it safe and use mono audio for phone and tablet distribution.
Steve Mann
MannMade Digital Video
http://www.mmdv.com -
-_- *groan*
I found something else… on phones, the audio works exactly as i intended it to be when you plugged in an headset or external speakers. Otherwise, the audio problem again. All internal phone audio chipsets are like this? I assumed they had to be stereo?
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This confirms my hypothesis – one of your stereo channels is inverted.
On the phone, the headphone jack is still stereo (for music), so even though one channel of your video’s audio is inverted, your ears will still hear the audio on headphones. When the stereo channels mix in the speaker amplifier for the single speaker in the phone, the inverted channel wipes out the non-inverted channel.
You will find very few pro videos on Vimeo or Youtube using stereo audio. It usually adds nothing to the video and it consumes some bandwidth that I would rather give to the video.
Steve Mann
MannMade Digital Video
http://www.mmdv.com -
Sigh… how do i make it mono in Vegas?
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The only thing i can think of is that all other audio was recorded with Rode shotgun microphone and Sony ECM-55 Lav microphone, BUT the boss intro audio was recorded with a ABC News microphone, you know, the one they hold on the news with the logo. That mic was plugged into the Sony a99 and was used as recording audio instead of the others.
Does microphone types have anything to do with inversion?
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nevermind it wasn’t even the microphones at all, the boss, Joe, and John cannot be heard in mono… this is annoying.
In what way can i uninvert it? I tried the invert button on the sidebar to the left of the tracks and that didn’t help.
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If the left and right channels are basically the same, then it’s real easy. Right click the audio event and select “Channels” then “Left Only” or “Right Only”.
Yes, the wiring of the microphone can affect the phase if the XLR connector is miswired.
Steve Mann
MannMade Digital Video
http://www.mmdv.com -
That worked! This was driving me nuts the whole time… Now i know. Thanks to you! Why is something like that so obtuse sometimes?
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It’s just experience. I made Karaoke discs for my daughter with this trick. On most music CD’s the music is stereo, but the vocals are almost always mono. (Movie sound tracks also – the dialogue is almost always mono). By duplicating the audio tracks, making one the left channel and the other the right channel, then invert one. You are left with the stereo bot the mono vocals are negated. It’s not perfect, and it introduces some distortion in the music, but it’s perfect for a teenager’s Karaoke party.
Steve Mann
MannMade Digital Video
http://www.mmdv.com -
[Stephen Mann] “It’s just experience. I made Karaoke discs for my daughter with this trick. On most music CD’s the music is stereo, but the vocals are almost always mono.”
In fact, for more professional studio recordings, each sound source is essentially recorded in mono. I would use one mic per singer, one or two per guitar cabinet or acoustic guitar (not for stereo effect, but for tweaking the character of the sound when mixing), three on a piano (88 sets of strings don’t get picked up properly with a single mic), three+ on a drum kit, many more if possible. I’ve even done this on “live in the studio” type recordings — whole band playing at once.
All this goes into a mixer, where the mixing engineer is placing each of these sound sources in a stereo field. And the lead singer is more often than not placed right in the middle of the mix. So that’s easy to cancel out.
You can sometimes play the trick with other instruments. Very simple mixing does nothing more than varying the level of a source left-to-right, so you can reverse that process and “pan out” other sources. Sometimes. More sophisticated stereo mixing uses levels and small delays… that’s hard to undo.
-Dave
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