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Fast Start Compressed Header - Compressor

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jack bibbo
Fast Start Compressed Header - Compressor
on Sep 25, 2008 at 8:01:36 pm

Hello I am using Compressor straight out of Final Cut Pro. I found a nice preset in the "H264 for Ipod Video at 640 x 480".

This is for streaming off our websites and the :30 spots look great.

However with this preset I can not find a place to adjust "Fast Start Compressed Header" so that it does not have to download all at once.

So logically I thought that I would create my own preset based off of their preset.

OK great, well it does not LOOK great at all right. Looks terrible and I believe that it is the Average data rate vs the Maximum data rate. They have a variable data rate 1.5 Mbps to 4 Mbps. This keeps it small in size and looks good. When I build a preset it only gives me the option to a. Automatic bit or b. Maximum bit rate. If I go max at 4Mbps then it way to big.

so I need to know can I either:

1. Make a preset and set a variable bit rate.
2. Take the IPOD setting that they have and make it have a Fast Start Compressed Header.

Below are the settings for both. 1st - their preset 2nd - mine.

(Theirs)

Name: H 264 FOR iPod video and iPhone 640 x 480
Description: H.264 video @ 1500 kbps, progressive, multi-pass. Audio is 44.1 kHz, stereo
File Extension: .mov
Estimated file size: 644.17 MB/hour of source
Device: iPod/iPhone VGA
Frame sync rate: 5 seconds
Video Encoder
Format: QT
Width and Height: Automatic
Pixel aspect ratio: Square
Crop: (L: 10, T: 10, R: 10, B: 10)
Padding: None
Frame rate: (100% of source)
Frame Controls: Automatically selected: Off
Codec Type: H.264
Multi-pass: On, frame reorder: Off
Pixel depth: 24
Spatial quality: 50
Min. Spatial quality: 50
Temporal quality: 50
Min. temporal quality: 50
Average data rate: 1.5 (Mbps)
Maximum data rate: 4 (Mbps)
Audio Encoder
Format: MPEG4
Sample Rate: 44.100kHz
Channels: 2
Bits Per Sample: 16
AAC encoder quality: high
Data rate: 128 Kbps

(MINE)

Name: Preset #1
Description: H.264 video @ 1500 kbps, progressive, multi-pass. Audio is 44.1 kHz, stereo
File Extension: mov
Estimated file size: 1.72 GB/hour of source
Audio Encoder
AAC, Stereo (L R), 48.000 kHz
Video Encoder
Format: QT
Width: 640
Height: 480
Pixel aspect ratio: Square
Crop: (L: 10, T: 10, R: 10, B: 10)
Padding: None
Frame rate: (100% of source)
Frame Controls: Automatically selected: Off
Codec Type: H.264
Multi-pass: On, frame reorder: On
Pixel depth: 24
Spatial quality: 75
Min. Spatial quality: 25
Key frame interval: 24
Temporal quality: 50
Min. temporal quality: 25
Average data rate: 4.096 (Mbps)



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Daniel Low
Re: Fast Start Compressed Header - Compressor
on Sep 25, 2008 at 9:36:59 pm

If you like the iPod preset then use that.

After it has transcoded the clip, open it up in Quicktime pro and choose Export.

In the Export dialog select 'Movie to Quicktime movie'

Uncheck the Video and Sound check boxes, check the 'Prepare for Internet streaming' box and choose 'Fast Start - Compressed Header'.

By the way, your crop values are wrong, cropping 10 pixels from each side will distort your 4:3 video image.

If your source in FCP is interlaced you need to deinterlace. Use Frame Controls

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Please post back saying what solved your problem. It could help others, and saying 'thanks' is free!


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jack bibbo
Re: Fast Start Compressed Header - Compressor
on Sep 26, 2008 at 12:20:55 am

Running it through QT Pro - will that recompress and further degrade quality?

How is equal crop on all sides distortion?

thanks





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Daniel Low
Re: Fast Start Compressed Header - Compressor
on Sep 26, 2008 at 7:36:54 am

No it won't decompress as you are 'switching off' any further video and audio processing by unchecking those boxes.

A video frame is not square obviously, therefore cropping an equal amount will distort it. Your crop values need to retain the 4:3 (or 16:9) aspect ratio. 10 pixels won't be much distortion but it's still distortion.

__________________________________________________________________
Please post back saying what solved your problem. It could help others, and saying 'thanks' is free!


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Daniel Low
Re: Fast Start Compressed Header - Compressor
on Sep 26, 2008 at 8:23:33 am

Sorry, recompress, not decompress!

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jack bibbo
Re: Fast Start Compressed Header - Compressor
on Sep 26, 2008 at 5:54:48 pm

So is that the only way to do what I was trying to accomplish - varibable data rate on my own preset. I would rather not have to bring it through another program if possible. We have QT pro but not on all machines.

I hear ya about the distortion. We do the 10 or 5 pixel crop to resemble the "action" of television. Distortion is minimal and unnoticeable.

Thanks thus far.





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Daniel Low
Re: Fast Start Compressed Header - Compressor
on Sep 26, 2008 at 6:33:56 pm

Try these cropping values:

720x480 – l/r 36 t/b 24 –
720x486 – l/r 36 t/b 26

They are TV safe area crops for NTSC.

Page 225 of the compressor 3 user manual will guide you through setting Fast Start Compressed Header up, or page 165 for compressor 2 manual

__________________________________________________________________
Please post back saying what solved your problem. It could help others, and saying 'thanks' is free!


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jack bibbo
Re: Fast Start Compressed Header - Compressor
on Sep 26, 2008 at 6:51:39 pm

excellent thanks for that.

Maybe you can explain something that I maybe overlooking:

if 4:3 is 1.33 pixel aspect ratio
and 640 x 480 is 4:3 and 1.33 pixel aspect ratio
then why is 720x486 consider 4:3 but the pixel aspect is 1.48

With that what would the cropping be on 640 x 480 to represent action safe and still be 4:3.

thanks for resolving my compression questions.





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Daniel Low
Re: Fast Start Compressed Header - Compressor
on Sep 27, 2008 at 12:53:43 pm

You're getting pixel aspect ratio (PAR) and frame aspect ratios mixed up:

640x480
720x480
720x486
720x576
768x576

Are all 4:3 (1.33:1) Frame aspect ratio

All have non-square pixel aspect ratios except 640x480 and 768x576 which have square pixels.

(N.B. 720x480 & 720x576 can also be 16:9 Anamorphic)

You crop the 640x480 with the same amounts as the 720x480

__________________________________________________________________
Please post back saying what solved your problem. It could help others, and saying 'thanks' is free!


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James Poulakos
Re: Fast Start Compressed Header - Compressor
on Mar 7, 2011 at 10:23:36 pm

I've tried doing this, that is, exporting from QT Pro without recompressing, just to get the "Fast Start Compressed Header" feature included in the file.... but QT Pro greys out the OK button unless I check either Video or Audio.

In other words, QT Pro is not letting me export a file with only the "Prepare for Internet Streaming" box checked.

This is as of Monday, March 7, 2011, using QuickTime Version 7.6.6 (1710) on Mac OSX 10.6.5... I assume QT is QT Pro on this machine because I'm a Pro Apps user with FCP, Compressor and Motion licensed and installed.

I'm not so much looking for a solution as sharing the info that this isn't possible... though a solution would be cool!

(Hmm, I did a 3-month search, and this thread from 2008 was the top hit. It seems relevant, so I posted here)


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Dave Mansueto
Re: Fast Start Compressed Header - Compressor
on Nov 3, 2008 at 10:38:34 pm

As far as I know the compressor 640x480 preset under apple devices does enable fast start.

I use that and upload those to our servers and it progressively downloads(plays right away).





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