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I love Sony Vegas, but………
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“Panning and zooming being very fiddly and often leaving borders around the zoomed shot”
I think you mean this question I had (and answered), posted at:
https://forums.creativecow.net/cgi-bin/new_read_post.cgi?forumid=24&postid=827665
Tim
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I’m not trying to figure out how to *set* the bitrate, rather how to determine what the bitrate is of an already rendered file.
This is from the Vegas help files:
24p video uses less space on a DVD, allowing you to add more video or use higher-quality video than you could with 60i video.So I’m still confused. According to Sony, a 24p mpeg2 file be smaller (significantly or otherwise) than a 30i mpeg2 file. But how much smaller? Let’s assume one file was rendered as a 24p DVD Architect video stream (in the 6,000,000 – 8,000,000 bitrate range), and the other as a 29.97 DVD Architect video stream (again, in the 6,000,000 – 8,000,000 range). What kind of size differences should I be looking for? I rendered the same 20 minute piece of footage — once as a 24p mpeg2 and once as a 29.97 mpeg2. The 24p file (rendered at a similar bitrate) was actually *larger* than the 29.97 file. What gives?!
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It’s all about the bit-rate…. repeat after me… it’s all about the bitrate.
A 24p project rendered (encoded) at the same bit-rate as a 29.97 project will result in VERY SIMILAR file sizes.
Am I making sense?
This answer was the same one I gave in my first response to you.
These files you are talking about – you rendered them right? Using Vegas? Yes? Then YOU can check out for yourself what the bit-rate was that YOU rendered them at. If you used the standard default templates then why don’t you just open up the custom properties of each template and check them out yourself.
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The bit rates are variable in the custom templates. So I know that both projects were rendered in the 6,000,000-8,000,000 ballpark, the custom settings. And I understand that it’s ALL ABOUT THE BITRATES!!
My confusion is a result of the line in Sony’s help files, the line I mentioned in my post: 24p video uses less space on a DVD, allowing you to add more video or use higher-quality video than you could with 60i video.
That line implies that using the same settings (including the same bitrates) and the same custom templates (which I did!), a 24p file should be smaller than a 60i file. I have not found this to be the case. And I’m simply trying to understand why.
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VERY helpful. Thanks for showing that program to me!
What I found was that Vegas, when encoding the same project, using the default settings, uses a higher bitrage for encoding 24p than it does when encoding 30i. The 30i file’s bitrate was even below the range Vegas uses in the default setting, which I found odd, but acceptable.
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[Marc] “That line implies that using the same settings (including the same bitrates) and the same custom templates (which I did!), a 24p file should be smaller than a 60i file. I have not found this to be the case. And I’m simply trying to understand why.”
You say you want to understand why… and yet you also say on the other hand it is “ALL ABOUT THE BIT RATES”. That… IS… THE… ANSWER. No further work should be required on your part to understand it any further.
I can appreciate that uou had some confusion initially… in that you made an assumption that the supplied default templates by Sony somehow were setup to create a 24p project that creates files that are identical quality to 29.97 projects and the files would be smaller. You have found out they are not… and that is because they have the same sort of bit-rate settings. Now you know that is the case… you can adjust the bit-rate settings in your 24p render and end up with smaller files.
ANy more questions?
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The way Sony’s post reads (24p video uses less space on a DVD, allowing you to add more video or use higher-quality video than you could with 30i video) makes it seem as though, all things being identical, 24p files would be smaller. It implies that you’d have to render 24p video at a higher bitrate or make it longer in duration to have it be equal in size to a 30i piece of video.
I ran two test renders, 11 seconds long, of some footage. Both were output as DVD Architect streams — one at 29.97, the other at 24p. Bitrate was set to a constant 6,000,000 bps for both. The resulting 29.97 interlaced mpeg file was 8.44 MB in size. The 24p file was 8.45 MB in size, larger than the 29.97 file, despite being the exact same video, rendered with the exact same bitrate as the 29.97 file.
So, if it is all about the bitrate, and 24p video should, at least, have 20% less information than 29.97 video (23.976 full frames versus 29.97 full frames), then why am I getting a larger file from the 24p video rendered with the exact same bitrate as the 29.97 video?
I’m not trying to be difficult here — this just doesn’t seem to add up.
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Marc,
I’ll be interested to hear Liam’s take on this, but my logic says – yes, the same bitrate will produce the same size (give or take a bit ….) BUT – the 24p should be better quality.
Peter Wright
Perth, Western Oz
http://www.allroundvision.com.au -
Was it
constant… or did you have Max, Avg, and Min settings at different values? In the end those values will also determine what the encoder chooses to do. In the end… I cannot claim to be any great expert on this… other than to “feel” I have an understanding (like Peter does) of how Bit-Rate plays into the file size thing. This comes from years of working with streaming files. Over the years the most common misconception is that people reduce the frame size – or the frame rate – and expect that to reduce the size of the file. When in actual fact… the bit rate is the only determining factor in file size.
I’ll run some tests myself on the 24p mpeg stuff to see what goes on in reality as well. Seems only fair.
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