T2i Magic Lantern + Rode Videomic - Gain vs No Gain

Derkoi

Derkoi

Well-known member
Hey,

I just managed to get the Magic Lantern firmware to boot properly on my 16GB card, and so I had chance to try out disabling the audio gain.

I made a quick video to let you guys hear for yourself, I think it works great. Hope it helps some of you guys who perhaps didn't know if the Magic Lantern firmware would work or not.

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I AGREE
 
nboyanov said:
Thanks for posting this! I did not realize there was a new one with agc turned off. cant wait to test it out.
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No problem, i figured a few people wouldn't have been aware of it.

There's a few issues on my camera with the firmware, might not be on them all though.

1. When using the firmware with AGC off & no mic plugged in, the on board mic doesn't work.

2. When I playback a recording there is no audio playback.

I'm sure these will get sorted soon & might just be on my camera, your mileage may vary.
 
Is there any benefit to the Magic Lantern Firmware update beyond being able to disable the AGC?

I've been getting great audio quality with the Rode mic going straight into the camera, no firmware update, and don't want to risk bricking my camera and frying my warranty for manual gain control.

If they came out with a bitrate hack equivalent to the GH1 hack, I'd definitely risk it to improve my visual quality.

Just not ready to take the plunge for the audio since the quality is also pretty solid - anyone with experience about the pros / cons of the firmware update I'd love to hear it!
 
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The benefits of the Magic Lantern firmware are huge in my opinion. Once all the features are implemented.


  • Features:
    • Onscreen audio meters
    • Lens data computation
  • Upcoming features:
    • Manual audio gain (not yet tested)
    • Headphone monitoring via A/V jack
    • Zebra stripes / histogram / waveform
    • Cropmarks
 
Derkoi said:
The benefits of the Magic Lantern firmware are huge in my opinion. Once all the features are implemented.


  • Features:
    • Onscreen audio meters
    • Lens data computation
  • Upcoming features:
    • Manual audio gain (not yet tested)
    • Headphone monitoring via A/V jack
    • Zebra stripes / histogram / waveform
    • Cropmarks
Click to expand...

Cool, thanks Derkoi. Any thoughts or info on a bitrate hack for the Canon cameras? A. is it within the realm of possibility, B. Can you see one coming any time soon?

I'm not a firmware master by any means, though I do try to keep on top of things.
 
I don't think it's possible but I dunno. Personally I hope Trammel gets the auto rack focus to work, that'd be awesome. :)
 
Torrey Meeks said:
I've been getting great audio quality with the Rode mic going straight into the camera, no firmware update...
Click to expand...

I watched your "Life in a Day." It really is well-done as far as shooting and editing, and it kept me watching to the end. Kudos.

Two things that stood out to me:

1) Your friends are interesting and/or a bit frightening. (That makes the story worth telling.)

2) I would not call that audio "great quality" by any stretch. It wasn't bad enough to make me turn the video off, but it wasn't good enough to be of note.

Regarding item #2, what AGC does is to try and ride the gain so that it's always recording at a very high level. So when the sound source suddenly drops, the AGC rushes in to turn up the volume, which also amplifies ambient noise and hiss. And I can certainly hear that in your video. Also, for louder sound sources especially, the AGC adds a "crunchy" artifact that comes from really bad compression.

The other challenge is that a mic on the camera is never a good idea for on-cam dialog. It is too far away to be angled properly, and too far away to record the dialog with enough strength in the voice to keep room reflections at bay. For interiors, it sounds like recording in a bathroom. For exteriors, there's just too much traffic in the background. The AGC makes this worse.

Again, I really loved the video... it's just that the VideoMic straight into the camera with AGC does pose major challenges.
 
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Derkoi said:
Without the AGC there's nothing stopping someone using an extension cable from the mic to camera now though. :)
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Correct. I was speaking in terms of non-defeatable AGC. Sorry for not clarifying. I have edited that post.
 
I may wait till a newer version if disabling AGC turns off the built in mic. I actually have a use for it. I usually record audio on the H4N and use plural eyes in FCP to sync everything to the audio from the built in mic (them mute or delete that). It really saves me a lot of time.

Of course, once the Magic Lantern firmware is working well I'd consider plugging straight into the camera...hopefully the quality is on par with the H4.
 
C2V said:
I watched your "Life in a Day." It really is well-done as far as shooting and editing, and it kept me watching to the end. Kudos.

Two things that stood out to me:

1) Your friends are interesting and/or a bit frightening. (That makes the story worth telling.)

2) I would not call that audio "great quality" by any stretch. It wasn't bad enough to make me turn the video off, but it wasn't good enough to be of note.
Click to expand...

Thanks C2V! That was my first project on my T2i and it got me fired up to be filming again. Before I got the T2i I was shooting on a 5-year-old Panasonic PV-GS150 : )

It was a trusty old battle axe - I did my first videos on it - and I learned a ton using it, but got despondent with the visual quality after awhile.

Haha, yeah, my friends are a motley crew. Met a lot of them through my video and film endeavors.

Thanks for your catlike ears and input on the audio quality. It's definitely not my specialty. I went from the PV-GS150 with an Audio Technica ATR-55 to the Rode Mic and T2i setup, so when I got my first batch of shots into post all I could think was, "OMG. This is amazing."

I definitely want pro sound, so knowing what's lacking and why in that department in invaluable.

C2V said:
Regarding item #2, what AGC does is to try and ride the gain so that it's always recording at a very high level. So when the sound source suddenly drops, the AGC rushes in to turn up the volume, which also amplifies ambient noise and hiss. And I can certainly hear that in your video. Also, for louder sound sources especially, the AGC adds a "crunchy" artifact that comes from really bad compression.
Click to expand...

Thanks for breaking that down for me. I was always a bit stymied by exactly what AGC did / what it tried to achieve, and what the drawbacks were.

(At the same time I upgraded from the PV-GS150 camera and AT-55 mic setup, I went from a 13-inch white MacBook to a MacPro after I got funding for a documentary. The whole package has blown me away and I'm hoovering up info as fast as I can.)
 
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Torrey Meeks said:
I definitely want pro sound, so knowing what's lacking and why in that department in invaluable.
Click to expand...

I know I link folks to this about every other day, but it really is an invaluable resource. You should get a copy of the "Sound for Film and Television" DVD that is sold through DVXUser. It's a great crash-course in sound, and explains a lot of what you need to know to get that pro sound. It's part gear selection, part technique.
 
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