Video encoding compression

[bbbbbbb45]

In Sony Vegas
I am rendering mpg2 1280 X 960 at a bitrate of 4,000,000
The videos come out pretty well but every minute of
video is rendered at 30 megabytes in size,
so a 5 minute video takes more than 150 megabytes of
hard drive space! I have seen high quality videos on
the internet rendered at about 11 megabytes per minute.
Is there any way to do this with Sony Vegas, or must I use
another program? I have tried reducing the bitrate but that reduces the quality.
Thanks,
K

[Baldrick]

Must it be in mpeg2? You can try h264/avc instead.

And I'm moving you to our video conversion section.

[bbbbbbb45]

Hi
I just tried avc, and I get an error message "An error occurred when trying to create the file..." when I tried rendering it. In any event I need a format I can upload to youtube.
Thanks,
K

[Baldrick]

Youtube will reconvert so it doesn't really matter what the file size is. If you haven't a slow internet connection then.

[Cauptain]

Hi
I just tried avc, and I get an error message "An error occurred when trying to create the file..." when I tried rendering it. In any event I need a format I can upload to youtube.
Thanks,
K

Use 960x720 for HD 4:3 file for Youtube.

Select Tablet 720 profile and change like a shot:





Claudio

[bbbbbbb45]

Hi, thanks for your comments
1) File size matters because while I upload to youtube, I want to keep backups

2) I tried making it an avc file using what Cauptain suggested, and while it worked, it cost 30 megabytes per minute--no better than mpg2.

Any other ideas where I can get high quality for about 10-15 megabytes per minute like professional videos?
Thanks
K

[jagabo]

file size = bitrate * running time

Using your 4,000,000 bits per second example:

file size = 4,000,000 bits per second * 300 seconds
file size = 1,200,000,000 bits
file size = 150,000,000 bytes

If you want a smaller file you have to use a lower bitrate. At low bitrates h.264 will give you better quality video than MPEG 2.

[_Al_]

Any other ideas where I can get high quality for about 10-15 megabytes per minute like professional videos?

Answer is not easy as you might think. One has to see what you are encoding and then we go from there.

Professionals use different workflow, technique, lighting, proper shutter speed, encoders and different originals, possibly 4k scans, they do not produce nice colorful noise in low light like we can do with camcorders .... You cannot compare your home video to scanned video from film.

There is no way to guess what bitrate you need, specially nobody seen your video. You run it through Constant Quality settings (x264) and you get idea roughly what bitrate encoder needs, otherwise it is a peekaboo game with guessing numbers and reality is hidden. After that CQ settings you know what encoder gives to a scene. Knowing that then, you know if you go lower it is a compromise and if you choose higher bitrate it is a waste.

[bbbbbbb45]

Thanks for your replies
1) sony vegas doesn't seem to have an option to encode in h.264
2) Is avc the same as h.264? When I encode in it, neither windows media play or vlc can open it.

Thanks
K

[Selur]

2) Is avc the same as h.264? When I encode in it, neither windows media play or vlc can open it.

1. yes, they are the same.
2. I think both have problems with raw h.264 streams (streams that are not in a container) other than that at least vlc should be able to playback avc material (windows media player need appropriate DirectShowFilter installed for playback)


----

file size = bitrate * running time

+ container overhead if the output is not raw (container overhead can be quite large if one for example uses m2ts)

[jagabo]

file size = bitrate * running time

+ container overhead if the output is not raw (container overhead can be quite large if one for example uses m2ts)

Yes, transport streams have significant overhead. Typically about 10 percent. Most other containers only have about 1 percent overhead. And, of course, there's the audio bitrate too.

[Selur]

it can also easily go up to 300%+ if you combine low bit rate with long running time,.. usually not the case most people encounter since they only use transport streams for high bit rates.
+ I don't think anyone figured a way out to anticipate the overhead when you multiplex thd inside a m2ts stream.

Cu Selur

Ps.: for those interested: http://forum.doom9.org/showthread.php?t=158828 + http://forum.selur.de/topic56-m2ts-overhead-calculation.html