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Exporting Small file for award contest
Hi,
At my internship I was asked to convert some video files for a contest our company is entering. I checked the contest’s guidelines and one of the guidelines is a video must be in 2 formats, mpeg and .mov. They also required certain bit rates and approx file sizes.
The mpeg file came out OK with their requirements, however, the .mov file doesn’t look as good. For a 30-second commercial they want a max bit rate of 60kbps and a file size of about 3MB. With those requirements, would you expect the .mov file would look too compressed or am I not going about this properly. I’m just trying to get other opinions so I don’t make my company look like asses at the contest.
(I brought the FCP quicktime reference file into Compressor and set up an export with their requirements)
Thanks,
Robert J. Grauert, Jr.
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6 Replies
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Hi Rob,
I think must be a mistake in the .mov specs.
60 Kbps is a data rate suitable just for a low quality audio file.
Think that people normally compress MP3 at 128 Kbps.
is impossible to do video + audio at such small data rate.
May be they meant 600 Kbps.
That data rate will allow you a very good quality H264 files for the web.
Also I don’t understand that they require such low data rate for the .mov when the .mpg (being MPG-1) will be around 1.3 Mbps.
Anyway I thought that a 60 Kbps .mov would be impossible to do, but I found a Compressor preset: Other Workflows> Web > Streaming> QT 7 Compatible> “H.264 40Kbps Streaming”
Rafael -
I think I did export around 600Kbps because 60kbps was smaller then the 3MB file size limit. So i thought to myself, “I should increase the bit rate to increase the quality and file size.” I did and the quality was better, but doesn’t look as clean as the mpeg video, which has a requirement of 8Mb/s.
They are using the mpeg file for the screening.
I will try the preset you found in Compressor. Thanks, Rafael.
Robert J. Grauert, Jr.
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Hi Rob,
this get more confusing for me.
You say that the .mpg is 8Mbps so I guess you are talking about an SD MPG-2.
What is the required size for the .mov?
rafael -
Sorry for being confusing.
Yes, one version is MPEG2 with an 8Mb/s data rate and 30MB file size at 720X576 resolution. I’m not having a problem with that though. I followed those guidelines and the exported product came out great.
What is giving me an issue is the .mov file. They want approximately 3MB file size at 60Kb/s at 320X240, but like you said earlier, they might mean 600Kb/s.
My question is: With those guidelines (for the .mov) would you expect the video to look too compressed/pixelated? I ask because my .mov DOES look a bit too compressed and pixelated, but if another pro says, “Yes, 600Kb/s is a low bit rate, so you are bound to have a pixelated image,” then I know I didn’t compress improperly, the contest holders just want a version that is more compressed since the videos will all be submitted through the internet.
Does that make sense? Sorry if this is a hassle.
Robert J. Grauert, Jr.
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[Rob Grauert] “Yes, 600Kb/s is a low bit rate, so you are bound to have a pixelated image,” “
H264 at 600 Kbps in a 320 x 240 picture will yield an incredible good quality. I’ve been using 450/500 Kbps with bigger size (480 x 270) and nothing to complain about the picture.
Lets do some maths;
They allow you 3 MB for 30′. So if the clip would be a 1 minute (same data rate) would be 6 MB.
6 MB for 60 seconds means 1 MB per 10 seconds. Thats means 100 KB each seccond of the clip.
So if they are allowing 100 KB per each seccond, you just multiply by “8” to get the data rate.
So 800 Kbps is the data rate that you can reach. I think that is a lot for a H264 at 320 x 240.
With that data rate your 30′ H264 clip will be 3 MB size.
This is for video + audio so you have to reduce a bit the picture data rate to acomodate the audio.
So set your H264 for a 575 Kbps data rate limit and the AAC audio for 224 Kbp.
Wonderful audio and video for a 3 MB file for 30 secconds.
Cheers,
rafael -
oh cool. I never thought of thinking about it mathematically. That is very handy.
Thanks again!
Robert J. Grauert, Jr.
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