Hi Fo
I have also recently signed up to this forum and am hoping to learn from others. However, in this instance, perhaps I can pay it forward. The file size is due to the video bitrate, as Danny said, but lowering the bitrate in Vegas is not the optimal solution to this challenge. The reason is the the MainConcept AVC CODEC implemented in Vegas does not provide good results at lower bitrates.
The Internet HD 720p setting defaults to an average of 8000Kb/s for VBR video and 192Kb/s for the audio. That is why 90 minutes of content will result in a file nearly 6GB in size. This CODEC only offers two distinct options CBR and VBR and not much in the way of fine tuning the results even though there are several such settings available in the H.264 specification. Reducing the bitrate using either of these options will soon result in obvious image degradation. The settings required for decent results will add at least 10MB per minute of content. One can obtain MUCH better results by running that 6GB file through an encoder that will allow one to take advantage of the other settings available in the H.264 specification.
Here is a walk-through using Handbrake:
1) Download, install and run Handbrake.
2) Click “Source”, then navigate to the 6GB file created by Vegas, select it and click “Open” to load it into Handbrake.
3) Click the “Browse” button next to “Destination” choose where you want to save the re-encoded file.
4) Select MP4 as your container and tick “Web Optimized” to allow for quicker playback starts when streaming.
5) Select the “Picture” tab and confirm that the width is 1280.
6) Select the “Filters” tab and ensure everything is set to off.
7) Select the “Video” tab and ensure the video CODEC is set to H.264, the FPS to “same as source” and the framerate to variable.
8) Set the x264 Preset slider to “very slow”, choose “still image” from the x264 Tune pull-down and confirm the H.264 profile is set to Main and the level to 4.0.
9) Select Constant Quality and set the slider to 30 (for now).
10) Select the “Audio” tab and choose “Auto passthru” from the CODEC pull-down to prevent the audio from being re-encoded.
11) Now, near the top of the Handbrake interface in the “Source” section, change the “Chapters” pull-down to “Seconds” and select a small range for test purposes – say 10 seconds (i.e. 00:00:00 through 00:00:10).
12) Click “Start” to render the file and then, once it is done, check the video quality in your media player.
13) If you detect visible artifacts, go back to the “Video” tab and set the “Constant Quality” slider to a slightly lower number, say 28, and then click “Start” to render again. You can repeat this step until you find a setting that provides acceptable quality.
14) Then go back to the “Source” section and change the “Seconds” pull-down back to “Chapters”, then click “Start” to render the complete file.
Using this method, one can easily get the video portion of the file down to less than 100Kb/s while still retaining decent quality. This means that the video will add less than 1MB per minute of content. I have done this several times in the past with great results. I have found an RF of around 30 is usually acceptable for 720p and have even achieved decent results with settings as low as 40 for 1080p.