I read here that each time a project is rendered you lose quality...
Any reason why? I sometimes render 3 or more times (depending on the changes)...
Thanks.........
Rendering
Moderator: Ken Berry
The simpilist answer is that each time you re-render you are actually re-compressing the file which in turn diminishes quality. Think of your original uncompressed .avi file as an orange. It starts off nice and round, full of juice. You compress (render) it in a squeezer. Now the orange isn't as round and full of juice anymore. You then take this squeezed(compressed) orange and put it back in the squeezer. What you now have is a sad looking orange without juice or just a few drops. 
That's why the recommended capture format is uncompressed .avi. This way you are starting with an uncompressed file, making whatever edits you wish and then when your are finished, you render to an MPEG.
That's why the recommended capture format is uncompressed .avi. This way you are starting with an uncompressed file, making whatever edits you wish and then when your are finished, you render to an MPEG.
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Trevor Andrew
erock1 wrote:It starts off nice and round, full of juice. You compress (render) it in a squeezer. Now the orange isn't as round and full of juice anymore. You then take this squeezed(compressed) orange and put it back in the squeezer. What you now have is a sad looking orange without juice or just a few drops.
Add a few shots of Gin I’m sure that will revive it. 
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Rich2Putt
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I am going to need some Gin by the time this is over
I have an analog Canon camcorder and ADS converter box to process from analog to digital.
My capture setting is "DVD" (VS9)...........with that said, do I change the capture setting to .avi ? And when my project is completed and I go to "Share" "Create File" I change the settings to MPG to render?
Am I confused, yes, do I need a shot of Gin? yes......
Thanks again........
I have an analog Canon camcorder and ADS converter box to process from analog to digital.
My capture setting is "DVD" (VS9)...........with that said, do I change the capture setting to .avi ? And when my project is completed and I go to "Share" "Create File" I change the settings to MPG to render?
Am I confused, yes, do I need a shot of Gin? yes......
Thanks again........
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jchunter
Rich,
With the ADS analog capture box, you can safely capture directly to Mpeg2, which is the format you will be using to burn your DVD. The box will be doing the hard work of digitizing your analog video and converting it to Mpeg. I have built a dozen or so analog projects this way.
As for editing Mpeg, I have run a number of experiments with video of resolution charts as well as moving video. I was able to capture and successivly re-render mpeg2 vidio 8-10 times with no measurable loss of resolution, when compared to AVI, when the bitrate was 8Mbps. You lose quality but you can't see it on a resolution chart. Coalman showed that below 6Mbps, one could begin to see compression artifacts.
John
With the ADS analog capture box, you can safely capture directly to Mpeg2, which is the format you will be using to burn your DVD. The box will be doing the hard work of digitizing your analog video and converting it to Mpeg. I have built a dozen or so analog projects this way.
As for editing Mpeg, I have run a number of experiments with video of resolution charts as well as moving video. I was able to capture and successivly re-render mpeg2 vidio 8-10 times with no measurable loss of resolution, when compared to AVI, when the bitrate was 8Mbps. You lose quality but you can't see it on a resolution chart. Coalman showed that below 6Mbps, one could begin to see compression artifacts.
John
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THoff
Also, Smartrender can not only greatly reduce the time needed to render, but it can also help maintain as much of the original quality as possible by not re-rendering portions of the video that haven't changed.
If you are simply cutting and splicing, adding transitions and titles etc. but not resizing, applying filters, or changing the bitrate, then Smartrender will take the nearest I Frame and subsequent P Frames in the source video and copy the data to the output video.
If you are simply cutting and splicing, adding transitions and titles etc. but not resizing, applying filters, or changing the bitrate, then Smartrender will take the nearest I Frame and subsequent P Frames in the source video and copy the data to the output video.
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Rich2Putt
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Thank you John & THoff...........
Let's see if I understand "smart rendering".
Once I complete a project and render it for the first time, view it after it was burned and then found some errors....when I go back to the project and make the corrections...I go back to "create file" and re-render. Is the re-render "smart render" meaning it's only rendering the changes I made the second time?
To make myself clear, once you render a project, any changes afterwards, "smart render" would be completed behind the scenes? (not noticable).
Any clearification on this would help me greatly.........
Let's see if I understand "smart rendering".
Once I complete a project and render it for the first time, view it after it was burned and then found some errors....when I go back to the project and make the corrections...I go back to "create file" and re-render. Is the re-render "smart render" meaning it's only rendering the changes I made the second time?
To make myself clear, once you render a project, any changes afterwards, "smart render" would be completed behind the scenes? (not noticable).
Any clearification on this would help me greatly.........
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THoff
I depends on what you mean by "make corrections".
If you started with a DV AVI file and transcode to MPEG, then SmartRender doesn't apply, even after you rendered it once completely, and then only make a minor change to a title before creating another MPEG file.
SmartRender only applies if the input and output file are compatible, i.e. you go from DV AVI to DV AVI, or MPEG2 to MPEG2, and always assuming that the output file parameters match the input file.
If you started with a DV AVI file and transcode to MPEG, then SmartRender doesn't apply, even after you rendered it once completely, and then only make a minor change to a title before creating another MPEG file.
SmartRender only applies if the input and output file are compatible, i.e. you go from DV AVI to DV AVI, or MPEG2 to MPEG2, and always assuming that the output file parameters match the input file.
Dude, why put yourself through all this time and trouble. Capture your footage to .avi. and make all your edits. Preview your project. Don't like something, just make further edits and preview again. Don't create render to an MPEG till your done. If you do create an MPEG, burn it to a DVD and then don't like it, throw out the DVD and delete the MPEG file you created. You'll still have the original VSP linked to all the oringinal .avi files. Just make your changes and make a new MPRG to burnRich2Putt wrote:
Let's see if I understand "smart rendering".
Once I complete a project and render it for the first time, view it after it was burned and then found some errors....when I go back to the project and make the corrections...I go back to "create file" and re-render. Is the re-render "smart render" meaning it's only rendering the changes I made the second time?
To make myself clear, once you render a project, any changes afterwards, "smart render" would be completed behind the scenes? (not noticable).
Any clearification on this would help me greatly.........
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Fuego669
Bearing in mind that AVI is just a container format and it's the codec that defines whether you are using a lossy, lossless, or no compression method.
For example Divx/Xvid streams can be written into an AVI file, but both of these formats are lossy, whereas something like HUFFYYUV is lossless and can safely be used to save some space (versus no compression) without losing any of the original quality. I tend to capture into AVI using HUFFYUV (http://neuron2.net/www.math.berkeley.ed ... ffyuv.html). My reason for using AVI is that it edits better than MPEG formats, from the perspective of cuts, etc.
No compression, or lossless compression, should be capable of being rendered, re-used as source and re-rendered ad-infinitum, without loss of quality or the introduction of artifacts.
Finally, my understanding of Smart Render is that it saves time when rendering a VS project as it simply uses previously rendered and cached clips, where no changes have been made to these clips in the current edit session.
However, so long as the source remains the same, each time you render the same project with Smart Render turned off, you should still get the same output each and every time; irrespective of how many times you re-render. Reasons for not using Smart Render are that it can inject problems due to VS bugs or inconsistencies.
That said THoff has pointed out above that Smart render can do a little more by not rendering source video that is already in the target rendering format.
At least that is my understanding of the above issues. Always willing to learn otherwise if anyone cares to comment.
For example Divx/Xvid streams can be written into an AVI file, but both of these formats are lossy, whereas something like HUFFYYUV is lossless and can safely be used to save some space (versus no compression) without losing any of the original quality. I tend to capture into AVI using HUFFYUV (http://neuron2.net/www.math.berkeley.ed ... ffyuv.html). My reason for using AVI is that it edits better than MPEG formats, from the perspective of cuts, etc.
No compression, or lossless compression, should be capable of being rendered, re-used as source and re-rendered ad-infinitum, without loss of quality or the introduction of artifacts.
Finally, my understanding of Smart Render is that it saves time when rendering a VS project as it simply uses previously rendered and cached clips, where no changes have been made to these clips in the current edit session.
However, so long as the source remains the same, each time you render the same project with Smart Render turned off, you should still get the same output each and every time; irrespective of how many times you re-render. Reasons for not using Smart Render are that it can inject problems due to VS bugs or inconsistencies.
That said THoff has pointed out above that Smart render can do a little more by not rendering source video that is already in the target rendering format.
At least that is my understanding of the above issues. Always willing to learn otherwise if anyone cares to comment.
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GeorgeK
Did anyone say Gin?
After reading all that lot, Now I am looking for some Gin !
Let me see if I can confuse you, Rich2Putt any more than the above lot.
1) Many video formats are lossy compression methods. So to is the JPEG format used for still images (photos). This means that when they convert your input (eg original) video file, say the video file you captured, to another format, they loose some of your video detail. This conversion process is called "rendering". Some video formats are not lossy. As said above, Uncompressed AVI is not lossy (because it is not compressed, that at least is simple to understand).
MPEG formats (MPEG2 and MPEG1) are both lossy formats so in converting from another format (say MPEG2 8000 CBR to a another format, say MPEG2 6000 VBR) there will be some loss of detail.
But be not too worried, as jchunter said
However if your like me and want to loose as little detail as possible. Then you have two solutions a) work with uncompressed AVI or b) only render when absolutly necessary. Since I do not have enough disk space for Uncompressed AVI, I have chosen the later, option b) rerender only when necessary.
2) You have UVS project, it contains one or more video clips, you add transitions or effects, sound, titles, etc. It is a work of art, your ready to create either a DVD or a video file via the "Share" tab in UVS. UVS re-renders your original video files to add your titles, sound, etc, to create a new DVD (or Video file, according to your selection, Create Video File or Create Disk).
When you review your work of art , as say a DVD on your TV, you notice that you had a title wrong (or say a music track that did not match the video or still picture), so you want to go back to your project.
No problem, open your project, and make your change to your title, then since you have not altered your original video files the next time you create a DVD or Video file, UVS re-renders your original video files to add your titles, sound, etc, to create a new DVD (or Video file, according to your selection, Create Video File or Create Disk). This is still only one re-render, not two.
However say you create a new Video file of transitions or effects, sound, titles, etc, and then decide to create a new project, using this file you created as a input (original) file, add more effects, etc, and the create a DVD or Video file. This time the ouput will be two re-renders from the very first video file you started with.
3) Now I want to explain Ulead's "Do not convert compliant MPEG files.
For exampe,say your original video, captured from the VCR is in MPEG2, 6000 VBR video, etc, you have set your project to these same video settings. You have added a Title overlay to the beginning and the ending of your video. Then you create a DVD using the same video settings (MPEG2, 6000 VBR video, etc). When UVS renders the project, it has to re-render the video overlayed by your titles, but when it checks your input (original) video which does not have titles or any other thing overlaying the video, it determines that the video format is the exact same and does not waste time to re-render the video but simplely copies the frames over without re-rendering them. This saves time by not re-rendering and saves quality as no re-render has taken place.
So back to the original concern, what to do?
My suggestion;
1) use the best quality capture you can afford to store your video in, for example, you can store uncompressed AVI (sometimes also called Raw AVI) easily, then use this format.
For me, MPEG2 does not take up a lot of space so I use MPEG2 8000 CBR.
2) Create projects in the same format that you captured in.
3) When you burn a DVD or create a video file, try to use the same video settings that you captured in, or if you want to fit more on the DVD disk, then settle for a lower quality setting. In this way, I only have at the most, one re-render or re-compression occurring.
However I think that jchunter is correct, even this is not requried as long as you do not re-render a piece of video too many times (he suggested 8 to 10 times), you will be hard pressed to notice.
Please let me know if this helps explain things.
Let me see if I can confuse you, Rich2Putt any more than the above lot.
1) Many video formats are lossy compression methods. So to is the JPEG format used for still images (photos). This means that when they convert your input (eg original) video file, say the video file you captured, to another format, they loose some of your video detail. This conversion process is called "rendering". Some video formats are not lossy. As said above, Uncompressed AVI is not lossy (because it is not compressed, that at least is simple to understand).
MPEG formats (MPEG2 and MPEG1) are both lossy formats so in converting from another format (say MPEG2 8000 CBR to a another format, say MPEG2 6000 VBR) there will be some loss of detail.
But be not too worried, as jchunter said
I doubt if you will notice the loss of detail.re-render mpeg2 vidio 8-10 times with no measurable loss of resolution
However if your like me and want to loose as little detail as possible. Then you have two solutions a) work with uncompressed AVI or b) only render when absolutly necessary. Since I do not have enough disk space for Uncompressed AVI, I have chosen the later, option b) rerender only when necessary.
2) You have UVS project, it contains one or more video clips, you add transitions or effects, sound, titles, etc. It is a work of art, your ready to create either a DVD or a video file via the "Share" tab in UVS. UVS re-renders your original video files to add your titles, sound, etc, to create a new DVD (or Video file, according to your selection, Create Video File or Create Disk).
When you review your work of art , as say a DVD on your TV, you notice that you had a title wrong (or say a music track that did not match the video or still picture), so you want to go back to your project.
No problem, open your project, and make your change to your title, then since you have not altered your original video files the next time you create a DVD or Video file, UVS re-renders your original video files to add your titles, sound, etc, to create a new DVD (or Video file, according to your selection, Create Video File or Create Disk). This is still only one re-render, not two.
However say you create a new Video file of transitions or effects, sound, titles, etc, and then decide to create a new project, using this file you created as a input (original) file, add more effects, etc, and the create a DVD or Video file. This time the ouput will be two re-renders from the very first video file you started with.
3) Now I want to explain Ulead's "Do not convert compliant MPEG files.
For exampe,say your original video, captured from the VCR is in MPEG2, 6000 VBR video, etc, you have set your project to these same video settings. You have added a Title overlay to the beginning and the ending of your video. Then you create a DVD using the same video settings (MPEG2, 6000 VBR video, etc). When UVS renders the project, it has to re-render the video overlayed by your titles, but when it checks your input (original) video which does not have titles or any other thing overlaying the video, it determines that the video format is the exact same and does not waste time to re-render the video but simplely copies the frames over without re-rendering them. This saves time by not re-rendering and saves quality as no re-render has taken place.
So back to the original concern, what to do?
My suggestion;
1) use the best quality capture you can afford to store your video in, for example, you can store uncompressed AVI (sometimes also called Raw AVI) easily, then use this format.
For me, MPEG2 does not take up a lot of space so I use MPEG2 8000 CBR.
2) Create projects in the same format that you captured in.
3) When you burn a DVD or create a video file, try to use the same video settings that you captured in, or if you want to fit more on the DVD disk, then settle for a lower quality setting. In this way, I only have at the most, one re-render or re-compression occurring.
However I think that jchunter is correct, even this is not requried as long as you do not re-render a piece of video too many times (he suggested 8 to 10 times), you will be hard pressed to notice.
Please let me know if this helps explain things.
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MikeGunter
erock1 wrote:
Dude, why put yourself through all this time and trouble. Capture your footage to .avi. and make all your edits ... make your changes and make a new MPEG to burn
A lot of wisdom here.
There are a few more tiny considerations.
In a TV commercial in the states, the spokesman says, "better... is an opinion." There's a great deal of truth to that.
Editing video in a computer requires some means of getting digital content on the hard drive by either IEEE1394 (Firewire), USB, or some other connection - perhaps a PCI card, etc., that either (1) transfers the digital content - the zeros and ones on a DV tape are the same 0s and 1s on the hard drive, or (2) converting analog to digital via some tool like ADS Pyro link or one of the Canopus ADVCs. There are many others, too.
MPEG compression in either MPEG1 or MPEG2 are very lossy. Recompressing adds artifacts, whether discernible or not - (yes, tree falling, woods, no one around, sound...).
If one is making cuts only video that will go to DVD or VCD, then likely there isn't any reason to use anything but MPEG content matched to the target output.
However, most of us don't do that. We add titles, overlays, color correct, and so on.
I recommend that one capture and edit in the least lossy format one can. Right now, that is DV AVI. It is compressed 5:1, but the encoding is top notch and the content only takes up 13GB per hour of content. Analog content can be encoded to Microsoft DV by any number of converters. One can use a DV camera with analog inputs to convert, too. Quality takes a hit due to generational loss in the conversion, but MS DV CODEC is the 'everyman' CODEC for the *least* lossy content. The recompression loss in DV is low.
One of the great VS9 strengths is its ability to work with many CODECs on the timeline and offer choice
VS9 has a neat trick to help recompression errors, too. One can import a VS project as a clip, so that one could have clip one on the main track, and a VS project on the overlay. The timeline will only process the data once.
Conversion from the timeline to MPEG2 should be clean, too.
Good luck and have fun.
Mike
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Rich2Putt
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Mike,
If I understand all of this, although I have an analog camcorder, transfering the data through an ADS analog to digital converter, I can "capture' in DV AVI.
After I capture in DV AVI, do all my edits, titles etc....in the time line
1)...I go to "share" "create file' and change the setting to MPEG2 (which will now render the project.
2)...Then go to create disk, add chapters etc ...and burn to DVD (setting at MPEG2)
Does this sound right?
If I understand all of this, although I have an analog camcorder, transfering the data through an ADS analog to digital converter, I can "capture' in DV AVI.
After I capture in DV AVI, do all my edits, titles etc....in the time line
1)...I go to "share" "create file' and change the setting to MPEG2 (which will now render the project.
2)...Then go to create disk, add chapters etc ...and burn to DVD (setting at MPEG2)
Does this sound right?