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H.264 vs. FLV problems in Workflow
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:
https://www.mckinneyontheweb.com/E63.htmlYou 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 512×288. 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 1920×1080. I wonder why not 1440×1080?
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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6 Replies
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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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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
1440×1080 HDV = 1920×1080 square computer pixels – Flix is getting that completely right.
Lastly H.264 is a MUCH higher quality codec than On2
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Fonts are like cologne:A bad choice speaks louder than a good one.
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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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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.
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Fonts are like cologne:A bad choice speaks louder than a good one.
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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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“So if you have movie.mov change it to movie.mov.flv or movie.flv. “
The facts::
https://theflashblog.com/?p=748
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Fonts are like cologne:A bad choice speaks louder than a good one.
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