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Quality loss when rendering mini-DVD
I´m using a Sony camera with mini-DVD´s. I record the movies in 16:9 PAL format. I am using Vegas pro 8 to edit my movies and DVD architect 4.5 to make the DVD:s. The movies looks ok, BUT there is some quality loss in the picture on the edited DVD´s. The quality loss in not very big – most people would not think about it – but I think about it.
My question is – is there anyway to render the movies in Vegas without ANY quality loss in the picture? I mean – it´s already in DVD-format from the beginning, why would there be any quality loss…
In the project properties area I use PAL standard/IMX Widescreen (720×576…), upper field first, Pixel aspect ratio 1,4568 (PAL DV Widescreen).
When I render the movies I use MainConcept MPEG-2 with customized template. I use:
Video rendering quality: Best
Output type: DVD
Frame rate: 25.000
Aspect ratio 16:9
Variable bitrate (max 9 500 000, average 6 000 000, minimum 192 000)Is there anyway that I could change my settings for the better? And is there anyway I can edit the movies and burn them onto DVD´s without any quality loss whatsoever?
Thanks!
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32 Replies
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If you do nothing but straight cuts and never add any color correction or other FX, then Vegas will simply copy the input MPEG to the output MPEG assuming your output has the exact same attributes. The problem comes when you start to add FX and transitions. Vegas has to render those and unfortunately, your camera is already recording in a highly compressed format that starts to degrade when re-rendered.
My advice: if you are serious about editing videos… buy a new camera that doesn’t shoot DVD quality MPEG-2. Those miniDVD cameras are meant for people who just want to “shoot and watch”. The sad thing is that camera manufacturers all claim you can edit the videos. Just because you physically CAN edit them, doesn’t mean that you SHOULD! (as you have seen) Unfortunately, they forget to tell you that part.
You are getting about the best quality you can given what you are starting with. Like I said, if you just do cuts, you should see the video preview display a message like “no recompression needed” while rendering which is telling you that it’s just copying from the source to target media with no loss.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
Thank you for your answer!
Well, I don�t think that I use any color correction or other FX that could cause the problem.
The only thing I�ve added is music and time marks (in Vegas) and subtitles (in DVD architect) and I don�t think that could cause the problem. I use the option “save project markers in media file” when rendering.
When rendering the movies, it says “no recompression needed” in the preview window from time to time (the text is shown very fast many times) – so I guess I�m ok on that area.
I have not made separate streams for video and sound, but is that really necessary to solve this problem? I have found this text in Vegas help menu though:
“If you’re using the MainConcept MPEG-2 encoder, use the DVD Architect PAL video stream template to render your video stream (you’ll need to render your audio stream separately according to the parameters listed in the AC-3 audio or PCM audio headings).”
As I said, I have added music in Vegas. I have added mp3-streams and DVD architect tells me – before burning the DVD – that the audio tracks will be compressed. DVD architect does not however tell me that any video files will be compressed.
To sum it up – why is the picture quality not exactly the same on the edited DVD I have made? Should I use separate streams for video and audio? The audio is fine now – I only want to improve the picture.
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If you are seeing the “no recompress…” message than the quality should be the same because Vegas is telling you that it’s just making a copy of the file. Rendering separate streams will not affect this. The reason it is suggested to render to separate streams is to keep your audio from being recompressed twice. Once to MPEG2 and then again to AC3. You’ll get higher quality audio if you only render once to AC3.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
Thanks again!
About the picture: As far as I can tell, the picture should be exactly the same on the Mini-DVD and on the edited DVD (although it´s not)… So the question is – where does the quality loss come from? I mean – if it was a question of me having the wrong settings in Vegas, i guess the preview window would not say “no recompress…”. And DVD Architect does not tell me that it does anything with the movie. Before I burn the DVD, I check “Optimize DVD” in DVD Architect and there is no warning sign of recompression of the movie at all.
About the audio: In my case – is render to .wav pointless? Should I use Dolby Digital AC3 Pro or Studio?
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I can’t say why the video looks different. It should not. Have you viewed this miniDVD on your TV? Is that what you are comparing it to? You might want to try taking a file right from the camera a burning it to DVD just to bypass Vegas and see if it’s DVD Architect? It really is strange.
As for the audio, render to Dolby Digital AC3 Pro using the Stereo DVD template and it should be fine.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
I do like this – I put the Mini-DVD in my DVD-player connected to a Sony LCD-TV (40″). Then I found a typical “weak” spot in the movie where the compression has made its mark. I try to remember the look of the weak spot and afterwards, I directly put in my edited DVD. The weak spot now looks somewhat different and even worse. I will try to see if I can solve this problem, perhaps I´ll get back to you if I have any more questions.
My last question for now is this: When the “No recompression..”-sign shows in the preview window during rendering, it is not constant. The movie keeps running and the “no recompression”-sign just blinks very often for like 10/100 of a second (sometimes you can´t really see the text, it goes so fast). Is that what it should be like? Or does the “no recompression”-sign show only a few frames that are actually not recompressed?
Thank you for your help!
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Oh, this is a strange thing that perhaps tells us that Vegas is the “problem” here and not DVD Architect. In Vegas, I imported a DVD Camcorder disc. The content was 1,26 GB. Then I took all the content to the timeline in Vegas and rendered the content. The “No compression”-sign showed during the process. I used MainConcept and did’nt do separate audio and video tracks. The rendered file is 896 MB. Could this difference (1,26 GB – 896 MB) be all related to the audio compression – doesn’t the video have to be rendered (and shrunk) for the difference to be this big?
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“No Recompression Required” should be on solid and not blinking. There must be something different about the MPEG-2 on your miniDVD and the MPEG-2 template you are using to render which is causing some rendering to take place. Maybe it’s the bitrate? or the GOP? but something is different. A video without audio is going to be smaller in size than a video with audio so the difference in size isn’t a bad thing.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
Hi Johan
[Johan Lundqvist] “Variable bitrate (max 9 500 000, average 6 000 000, minimum 192 000)”
I think you’re way off with the 9,500,000. It’s too high and that may be the cause of your problem.
There’s been may threads here suggesting you never go over 8,000,000. Also personally I use 2,000,000 instead of 192,00 for the low end.
Allen
ASX Media Group, Inc.
http://www.asxvideo.com
NEW DVD – Europe, Trains-n-Trams -
Changing the values on variable bitrate does’nt help me…
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