Video quality degrades

[John Rofrano]

[Pat Adams] “However, when I trim a clip and add it to my timeline, the picture softens and becomes a little fuzzy.”

What are you using to determine this? If you are looking at the preview window in Vegas Pro then you can control how much quality it uses but be warned that greater quality means potentially jumpy playback. If your preview is set to Preview (Auto) it’s OK for it to look a little fuzzy. It’s just a preview. if you set it to Best (Full) it should be great quality again. The preview quality has nothing to do with the actual footage. When you render, it switches to Good (Full) by default so that’s how your output will look. You should leave it at Preview (Auto) while editing for best playback performance.

~jr

http://www.johnrofrano.com
http://www.vasst.com

[Pat Adams]

The problem is that my actual rendered video itself was soft/blurry looking – unlike the original imported clips – looking just as it did in Preview (Best), which I had been using. I just did switch to Preview (Auto) on your suggestion and will try it that way by re-importing several clips and seeing if they’re sharper in the final rendered product.

Perhaps my Render Settings are not optimal either, since I’ve seen several different variations on what is considered “Best”.

I may need advice on the definitive best render settings as well.

Thanks for your reply, John!

[John Rofrano]

Changing the preview will have no affect on the output.

What render template did you use?

~jr

http://www.johnrofrano.com
http://www.vasst.com

[Pat Adams]

I’ve used a variety of settings, including variable bit rates, based on tutorials. This is the one I used just a few minutes ago. I’m using Vegas Pro 12, if that’s important.

[John Rofrano]

That template should yield very good results.

Is your source video 720p?

~jr

http://www.johnrofrano.com
http://www.vasst.com

[Pat Adams]

The source video (.mp4) is:

Frame width: 720
Frame height:402

Data rate: 903kbps
Total bitrate: 1034kbps

Could the source be the problem?

[John Rofrano]

[Pat Adams] “Could the source be the problem?”

Yes indeed. Your source video is 720×402 and you are rendering to 1280×720 which is 3 times the size! That’s where your softness is coming from. Your source bitrate is 1034kbps which is also very low. The problem is definitely your source which is lower quality than SD and you’re render it as HD. Try rendering to 720×402 and see if it looks better.

~jr

http://www.johnrofrano.com
http://www.vasst.com

[Pat Adams]

I thought a vid could be rendered however one likes if the source and project were the same. I see I was wrong.

I did just as you suggest and rendered at 720×402. It looks pretty good but far from perfect so am I correct in assuming that considering the source video I’ll never get great results?

I’ve added “Sharpen” from Media FX to all clips and that helped as well.

Thank you for your patience in replying. The technical side of Vegas is going to take some time to learn.

I’m sure I’ll be back with more questions.

[John Rofrano]

[Pat Adams] “I thought a vid could be rendered however one likes if the source and project were the same. I see I was wrong.”

There is a saying, “You can’t make a silk purse out of a sows ear”. Creating resolution where there is none is hard to do. You can render smaller and get great results but any time to render larger there will be an averaging of pixels to create new ones. These will never be as accurate as if the original image was larger to begin with. It has nothing to do with the source and project being the same size and everything to do with the source not having enough pixels to accurately represent the image.

[Pat Adams] “I did just as you suggest and rendered at 720×402. It looks pretty good but far from perfect so am I correct in assuming that considering the source video I’ll never get great results?”

Yea, pretty much. That’s why I mentioned the low bit rate problem. Not only is your video small, it doesn’t use a lot of data to represent the image. Let’s do the math: 702×402 is 282,204 pixels. Each pixel requires 1 byte (8 bits) to represent it. 282,204 x 8 = 2,257,632 bits per frame. 2,257,632 bits x 30 frames per second is 67,728,960 bits per second. So uncompressed your video requires 66,142kbps and it’s only using 1,034kbps. That means it must be compressed 66:1. That’s a LOT of compression which resulted in a large loss of quality.

Video that has marginal video quality may look fine, but once you re-render it, the quality starts to degrade rapidly. That’s another way of saying, Don’t expect your rendered video to look as good as the source because there just isn’t enough bits there to work with.

~jr

http://www.johnrofrano.com
http://www.vasst.com

[Pat Adams]

Got it! Your advice also made me realize I was doing something else wrong, but all in all, I’m much more satisfied with my results and happy now that I more or less understand the “why” of my problem.

Many thanks!

ETA:

If I have some clips in my movie that are 1920x1080p, e.g. and others only 720×402, I assume I should render according to the smallest size, but will the 1080 clips look worse this way, or will there be no change in the quality of the rendered video?