Burned by bitrate I think

Started by evnewsphoto, July 26, 2012, 01:44:20 AM

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evnewsphoto

Still learning this stuff but I just got burned by having the bitrate set too low I think (.2 I think it was) and resulted in my video being very pixelated! I checked it after I brought into Final Cut Pro on my 13" macbook and looked fine but now that I have started editing it on a larger monitor I immediately realized it is pixel city, large chunky ones, like a low res video even though I was shooting 1080! Of course I deleted the raw from my card, looked fine on small screen and I had backed it up on 3 drives. Too late I guess.

So what bit rate should it be set at? 3.0 the max? Or something else? This was the first major shoot I used ML on and so annoyed that it looks so bad now. I don't want to get burned again. Thanks,  Everett


KarateBrot

I wonder why you even experimented with the settings on your first major shoot  :o
1.0 is fine for most cases. But of course you can change the bitrate to your liking. Just test the bitrates. That should be the best solution
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johndb

1.3, 1.4 or higher depending upon on-board audio use. I would advise testing before you do a serious shoot.
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evnewsphoto

I should explain that I was not experimenting, I think I somehow changed it by accident. I have already been frustrated by trying to adjust one thing in ML and hit one of the four arrow keys while trying to push the set button and suddenly I am in the next menu over and did not notice that I changed that setting. I did start with the default settings but quickly became frustrated with the Auto ISO setting that was over exposing my nicely lit interview and I have no idea if at some point in paging around I changed the bitrate. I guess lesson learned and I know to check it! It is my fault and I am not blaming ML just mad that it looks so crapy.

So yes I am running audio as well, using a Beachtek DXA, so what should it be then? If I set it for 3 is that not going to work? I have high speed cards. Thanks for the advice, Everett

a1ex

Hint: potentially dangerous settings are displayed in red.

Malcolm Debono

Hint 2: Hide dangerous items / items you don't use using the Menu key - no more accidentally changing settings and much faster to browse menu  ;)
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evnewsphoto

How do I hide a setting? I don't think I saw that in user guide. Thanks Everett

Malcolm Debono

While in ML menu (the one that opens when pressing the trashcan button), press the Menu button to enter editing mode. You should see that the highlighter now becomes red. To hide an item, simply highlight it (using arrows / scroll) and press the Menu button. It should become greyed out. To enable it again, press the Menu button again. If you exit and re-enter the ML menu, all hidden items will disappear. Press the Menu item to go into editing mode again if you need to access any of the hidden items or make them visible again.
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nanomad

That feature is a new addition of 2.3 and it's explained both in the manual AND the 2.3 announcement  ::)
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evnewsphoto

Ok, I just updated to the new version and yeah now I see how to hide stuff using the menu button (it turns red).

So back to my original bit rate question; it is set to 1.0x and says (FW default), if I set it higher like to the max of 3 would that give me the highest quality or is 1.0x as good as the higher ones? I remember someone else saying 1.4 or higher if I am using audio (which I am- Beachtek) so is the default of 1.0x not high enough?

In the user guide it says;

• CBR: constant bitrate. You specify a factor for multiplying default video bitrate, between 0.1x and 3x. CBR 1x is the firmware default setting.

not sure what that means

• QScale: constant quality, variable bitrate (VBR). Available values: -16 ... +16. Lower numbers mean higher nitrates.

Have no idea what those numbers are but  constant quality sounds like what I want.

• Firmware default: completely disable bitrate control.

so that is what the FW default means? If so then is that what I want always?

I think I know but what is bit rate after all? Is it the size of the file or is it something to do with compression?

Thanks, Everett

1%

do 1.1 or 1.2 You should get something decent. I don't like FW default it sets it too low, compares unfavorably to HV-20.

CBR scales the individual parameters of the h.264 encoder. "VBR" just locks the quality parameter and lets canon do the rest.

You're not going to get much above 60mb/s with audio and a regular card. HDV was like 20-30mbps but I think mpeg2 was a little less compressed.

Also, ISO/Lighting/Motion all affect the bit rate. 3.0x might work in a dark hallway but go outside and buffer is gone in seconds (movie stops).

QuoteIs it the size of the file or is it something to do with compression?

Both. But I don't think we're using the encoder at full potential yet.

Also remember that higher bit rates can stop recording if your card can't keep up.