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HD Video Compression - Several poor MPEG-4 Symptoms

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Tom Wille
HD Video Compression - Several poor MPEG-4 Symptoms
on Oct 29, 2012 at 4:58:48 pm

Hello,

In my line of work, I am in constant need of hi res (1080p) video to be shrunk down to 100-300 mb while the video is 4-6 minutes long. Sometimes I'll download video and it will be 4 minutes long, 27 mb and it looks crystal crystal clear, so I know it can be done!

I usually export a non selfcontained file from final cut and then put on the mp4 setting in apple compressor. I feel like it used to work much better than it does nowadays. I've been getting a lot of visible pixels and the file size is okay but still, I've seen smaller look better! .mov and h.264 compressions always come out to be way too big. Another symptom is that when I give clients mp4 files, half of my clients come back to me saying things are out of sync and then I have to work them through the process of downloading VLC and then that always works, but it is a pain.

Any suggestions would be helpful!

Thanks.


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Craig Seeman
Re: HD Video Compression - Several poor MPEG-4 Symptoms
on Oct 29, 2012 at 5:12:41 pm

Simple math:
Duration times Data Rate equals file size.
Lower the data rate and you lower the file size (and lower the quality though).

Quality is related to bits per pixel (but a bit more complex so it's just a guide)
Bits Per Pixel equals Data Rate divided by the total of Frame Rate times Frame Size (in pixels).

Apple's H.264 is probably the least efficient of the major H.264 encoders.
x264 is probably about the most efficient. Telestream Episode has an x264 option and Sorenson Squeeze includes it.



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Tom Wille
Re: HD Video Compression - Several poor MPEG-4 Symptoms
on Oct 29, 2012 at 5:23:17 pm

Thanks for the reply, Craig.

In order to save some money on those other two products, what would be your recommendation in Compressor? mp4 with a max bit rate, Apple ProRes, other?


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Tom Wille
Re: HD Video Compression - Several poor MPEG-4 Symptoms
on Oct 29, 2012 at 5:31:20 pm

Additionally, how do you think I come across super small video files that look amazing, or download a 2 hour digital copy of a movie that is crystal clear yet only 1.5-2 GB? If I compressed something 2 hours long 1080p it would be at least 12 GB.


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Craig Seeman
Re: HD Video Compression - Several poor MPEG-4 Symptoms
on Oct 29, 2012 at 5:53:02 pm

[Tom Wille] "how do you think I come across super small video files that look amazing"

They're probably using x264 as I noted above.

What you should do depends on what your target really is. It's not at all clear to me.
You mention a "need" but no explanation as to why you have that need.
The H.264 codec is the most efficient commonly used codec.
For best results do a 2 or MultiPass VBR encode with Frame Reordering on targeting the data rate that will get you to the file size you need.

Compressor does not do High Profile encoding. It does not do CABAC entropy encoding. It does not give you control of the GOP structure or reference frames. These are all things that can improve quality at a give data rate.



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Tom Wille
Re: HD Video Compression - Several poor MPEG-4 Symptoms
on Oct 29, 2012 at 5:57:34 pm

Thanks. I actually need the file sizes smaller because a big client uses the videos in PowerPoint and anything higher than 200mb usually crashes it.


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Craig Seeman
Re: HD Video Compression - Several poor MPEG-4 Symptoms
on Oct 29, 2012 at 7:06:49 pm

Figure out the file size as per the formula I posted.
You have to consider whether the client really needs 1080 files. A smaller frame size improves quality.
You have to understand the basic concepts I posted in order to learn how to target.



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