YouTube is well known for being the busiest video sharing site, but unfortunately YouTube uses the much older Sorenson Sparke codec for their video encoding. This was the "improved" video format for Flash 7 but is based on the very old H.263 video conferencing codec. Even when new this was an old, inefficient codec.

Many people send YouTube an already compressed video, similar to what you'd put on your website and are disappointed when they see the quality that results on YouTube. That's because most of the information was first thrown away by the encode before upload, so there was little quality left to be encoded to Flash 7.

The goal is to give YouTube a master that they can use for encoding.

YouTube have two limitations: no more than 10 minutes per video and no larger than 100MB per video.

YouTube converts everything that is uploaded to Flash 7 video at 320 x 240.

Remember the good old days of VHS distribution? You wouldn't give the duplicator a VHS copy of the show to duplicate. No, you'd give them the highest quality master you could. Therefore, to get the best quality from YouTube, give them a high quality "master" that is close to 99MB.

Use any application that exports to .mp4 with H.264 video, including QuickTime (Player) Pro; Final Cut Pro, Sony Vegas, et. al.

• Export as MPEG-4 with H.264 and set the size to 320 x 240. There is no point providing more resolution than YouTube's finished size. By going direct to that size means that you can devote bandwidth to making that master look great, instead of sending excess size that will be scaled down. Bonus is that you get to control de-interlacing and scaling.

From here on there are two choices: calculate the maximum data rate that will keep the file under 99MB or use some general purpose settings.

General Purpose Settings - up to 6 minutes

A simple way to ensure that the quality is there is to export to MPEG-4 with:

• H.264 video at 2000Kbits/sec (2Mbits/sec or 250KBytes/sec)
• 320x240 video size (deinterlaced or simply use one field)
• Mono audio with AAC at 64 Kbit/sec (or 128 Kbit/sec for stereo)
• Recommended Sample Rate and
• Best Encoding Quality.
• In the Video Options Main Profile should be checked on and Best Quality (Multi-pass) is advised for best quality.

These settings will be fine up to 800 Mbits aka 100 MBytes. At the proposed settings, any file shorter than 6 minutes and 15 seconds will be within YouTube's 100MB per upload limit.

If your video is longer than that but still less than 10 minutes then you're going to have to do some math to work out the maximum data rate you can afford.

Calculating Data Rate 6 to 10 minutes

This method requires you to know the duration of your video in seconds.  If it's less than 375 seconds (6 minutes 15 seconds), use the General Purpose settings above, if it's more than 375 some calculation is required.

• We have 800 Mbits to work with (100 MBytes x 8 bits-per-Byte).
• If we divide that by the number of seconds to be encoded we get our maximum bit rate per second.
• After deducting the 64Kbits/sec for mono audio or 128Kbits/sec for stereo audio, the remainder is the maximum data rate is the data rate for the video. Two pass will be important for this.
  

Let's consider an example.  The video is 8 minutes long that's 480 seconds.

• 800,000KBits divided by 480 seconds gives us 1,666,667Kbits/sec to keep within the 100 MB upload limit.
• Less 128Kbits/sec for stereo audio (or use mono and subtract only 64Kbits/sec) leaves 1538Kbits/sec for video.

So in the Data Rate set 1500 kbits/sec instead of 2000.

If you want to see an example uploaded using this method, click on the link below. This is a particularly difficult source to encode - fast flashs, leaves, lots of motion and yet, the quality is very high compared to the quality with other YouTube videos.

     http://www.youtube.com/watch?v=ZnTe-CI-hU8  

NOTE: More compression recipes like the above are available in Simple Encoding Recipes for the Web.