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H.264 vs. FLV problems in Workflow

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Jeff mack
H.264 vs. FLV problems in Workflow
on Feb 18, 2009 at 9:10:18 pm

Sorry to ask a deep question here and appreciate not being told to look up a thousand articles. Thanks is advance.

So I got this gid to do short 1 minute videos at the local flea market. I shot this video in HDV 1080i60 with my Z-1. I captured with easy HDV 1080i in FCP. Did a simple edit and exported non self contained. Then I used Flix Standard and encoded to FLV and posted here:
http://www.mckinneyontheweb.com/E63.html

You see how the picture looks VERY soft and blocky? My original footage was very crisp and clean. Now here's the problem.

With Flix standard, I used the preset for 300Kbs. When I open the edit tab, there are not many variables. First, I set the outpute frame size to 512x288. Then set the frame rate to 29.97. I then set the keyframes to 60 and in this case I used constant bit rate for streaming with max at 260Kbs vs variable for download. When I play the resulting file, it looks like crap. I tried switching to a higher bit rate (512Kbs) preset with Max BR at 448. I tried changing the keyframes to 15, I tried variable and nothing improves the picture much. The encoder sees the source BTW as 1920x1080. I wonder why not 1440x1080?

I then went into compressor and tried H.264 and did the same sort of tests. The only thing I didn't try was 2 pass.

Here's another question. The footage in the link has not been deinterlaced. Do I need to use compressor to deinterlace before going to the web? Obviously it takes a long time. I have right now 50 or so of these short vids to do quickly. And then about 100 per month all at one time.

When I see some video on demand on the net, the footage looks as if it were native. I know enough to be dangerous but not enough to get a good image.

Last thing, this file is on my server and I am going to start hosing the files to a streaming server and use embed code on my web page. Any comments are greatly appreciated!

Jeff


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Jeff mack
Re: H.264 vs. FLV problems in Workflow
on Feb 18, 2009 at 9:20:47 pm

One last thing. I just did another test with H.264 in Compressor and this time I used 1000 Kbs bit rate and it looks great! I also did NOT deinterlace. Will viewers have a hard time watching this vid due to the encode rate or will it simply just increase the file size?

Jeff



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Daniel Low
Re: H.264 vs. FLV problems in Workflow
on Feb 18, 2009 at 11:07:18 pm

You need to deinterlace.

Your keyframe setting should be set to force a keyframe every 5-10 seconds or every 150 to 300 frames - I'd suggest every 250 frames for your content in the link. (The encoder will insert keyframes automatically when it thinks it needs to).

The edit you posted in the link is going to need a higher datarate, there's lots of motion (pans and zooms) and lots of tiny detail. You need to think about 'Shooting for the Web', minimise all motion, shoot wide then cut to close rather than panning and zooming all over the place

The clip 'pumps' because you've set the keyframes for too often.

Flix 'standard' is just not very good really - you can't expect great results from it. compressor is MUCH better but you'll need to invest some time learning and experimenting to get the best out of it. Preset are only a starting point never good as a final setting

1440x1080 HDV = 1920x1080 square computer pixels - Flix is getting that completely right.

Lastly H.264 is a MUCH higher quality codec than On2

__________________________________________________________________
Fonts are like cologne:

A bad choice speaks louder than a good one.


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Jeff mack
Re: H.264 vs. FLV problems in Workflow
on Feb 18, 2009 at 11:54:17 pm

Thanks Daniel, Hoped you'd answer. Listen, I did an H.264 in Compressor and it looked great at the 1000Kbs preset. I made the keyframes 30. I thought the more keyframes you have, the better the interpolation but you say make it 250. I don't understand. Will the 1000Kbs choke my viewers or does that not matter except for the encode time? Also, I did not check the deinterlace in the frame controls but on the overview, it said deinterlace fast averaging. Does H.264 in Compressor automatically DI? And why is there a check box in the video filter tab if so?

Jeff



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Daniel Low
Re: H.264 vs. FLV problems in Workflow
on Feb 19, 2009 at 12:15:56 am

Too many keyframes usually hurt quality, it's too much to go into here but you should let the codec decide when to insert keyframes, with you forcing them every 5-10 seconds depending.

the higher the datarate the longer it will take to download, most computers should be able to play it back, it's not like you are streaming it.

H.264 does not automatically deinterlace, in compressor you have a number of ways to deinterlace, the one you chose is the lowest quality. Use frame controls for the best results.

__________________________________________________________________
Fonts are like cologne:

A bad choice speaks louder than a good one.


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Elijah Lynn
Re: H.264 vs. FLV problems in Workflow
on Feb 19, 2009 at 12:50:26 am

Just so you know. Flash Player 9+ supports H.264 so you don't really need to encode to .flv at all. Just add or change the extension to *.flv and link to it from the code. It will work nicely.

So if you have movie.mov change it to movie.mov.flv or movie.flv.

On my limited inexperienced experience H.264 smokes FLV.



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Daniel Low
Re: H.264 vs. FLV problems in Workflow
on Feb 19, 2009 at 7:49:17 am

"So if you have movie.mov change it to movie.mov.flv or movie.flv. "

The facts::

http://theflashblog.com/?p=748




__________________________________________________________________
Fonts are like cologne:

A bad choice speaks louder than a good one.


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