Method 2: Editing DVD footage directly.


You have avs files which decode and filter DVD footage all ready for editing... but there's a problem.

Many video editing applications do not like .avs files by default. Some programs require plugins and other programs have to use what is known as an 'avi wrapper' to make the programs read the avs files. Which method will depend greatly on your editing program.

a) Adobe Premiere 5.x, 6.x, and Pro 1.x - Premiere can use .avs files directly thanks to an import plugin which is included in the AMVapp.

b) Vegas Video - there is a plugin developed at debugmode.com to import avs footage into Vegas. I have not tested this, however so you are on your own :)

c) Programs with no other .avs support - In order to use .avs files in programs like Windows Movie Maker, Adobe After Effects, Ulead Movie Studio Pro and so on, you need to use an avi wrapper. This guide will show you how this is done but be warned that it is an experimental method.

Choose your method:

Adobe Premiere 5.x, 6.x, and Pro 1.x

To edit with your avisynth files in Premiere, you will need to download the latest Premiere Import Plugin. If you have downloaded and installed the AMVapp then you should already have it installed.

If you have to install it manually then copy it to your Premiere 'Plug-Ins' folder.

One you have this installed, it will allow you to open AVISynth (.avs) files in Premiere.

Speed

Using avs files can be slow or fast depending on how much processing has to be done by Avisynth. With DVD footage, seeking and rendering will be slower than with a huffyuv avi file.

What I recommend is that you get yourself a fast codec (like the PICVideo MJPEG Codec or the mjpeg codec in ffdshow) and select this as the codec in your "Project Settings". This will be the codec used for previews. You can always use a different codec later for exporting but this one is great for fast renders - especially when set to a low quality level. So, if you need to see if something has timed correctly, mjpeg codecs are great for that as they are very quick to decompress when set at low quality. My approach is usually to place a clip on the timeline, adjust it to fit then press Enter to render it, so I can see if it synchs.

However, if you find that it's too difficult editing with footage this slowly, then please use method 3.

Note also that this method of using footage is slower if you use deinterlacing/IVTC techniques in your avisynth script to remove interlacing. Again, if you find that it's too difficult editing with footage this slowly, then please use method 3.

Quality, Stability and the Premiere AVS GUI

The new Premiere plugin, developed by fellow amv-ers, contains a GUI which can change the quality of the footage you import into Premiere and it can also set up memory options to make AVS useage more stable.

When Premiere asks for a frame which is a different size than your source (preview window, timeline or exporting at a different size) the avs import plugin has to resize it. To do this there are 4 different resizers that you can choose in the GUI:

Premiere AVS Plugin GUI

As you can tell by the descriptions, low-quality resizers are fast and high quality resizers are slow. So what I recommend is setting the algorithm to Nearest Neighbour as this will ensure the timeline thumbnails and monitor previews will be the fastest they can be. When you export, however, you will want to change this to one of the other settings as Nearest Neighbour is poor quality.

The slowdown with the better resizers isn't that much though. With a quick 1000 frame rendering test it took 31 seconds with Nearest Neighbour, 34 seconds with bilinear, 36 seconds with Bicubic and 37 seconds with lanczos3. So, if you don't mind that amount of increase then you can keep it high quality all the time.

The right hand section of the GUI changes the Set Memory Max preferences in avisynth. Avisynth is not usually designed to process multiple avs scripts at once and as a result the memory can get used up really fast when processing multiple scripts. This can lead to avisynth crashing halfway through a render. To avoid this you can set the maximum memory allowed by each script. This option currently only works with Avisynth 2.5+ (which comes with the amvapp). The default setting is 64mb but if you are usuing lots of scripts you may want to reduce this to avoid memory crashes. It's a tricky thing to set, however, as some scripts which have a lot of processing may need a lot of memory and could crash if you set it too low - don't go below 16mb unless you really have to.

Errors, bugs, limitations and other things to avoid

Using avisynth scripts in Premiere can be a delicate matter. There are a number of things you should do be aware of when importing avs scripts into Premiere:

1) Check that the script works in VirtualDubMod. If you open a faulty script in Premiere you will just get a small 10 second clip containing an error message.

2) Make sure your avs script is creating an RGB32 output  By adding ConvertToRGB32() to the end of your script, you can make sure that the footage is in the correct format for processing in Premiere. Also, 24bit RGB support in the import plugin is sometimes problematic and will sometimes give you a clip in pure black rather than the footage you want. Converting to RGB32 will avoid this.

3) Don't slow down clips too much. If you slow down clips in Premiere to very very slow speeds (like <10%) then it might crash avisynth when you try to export or reload your project. Do not do this. Either make a still and use that or if it crashes when applying lots of filters, try and pre-render the section with a lossless codec.

4) Do not change your script whilst Premiere is open. It probably won't crash but if Premiere is expecting a 1000 frame file and you change something and give it a 30 frame file then any clips that no longer exist in the new avs file will be converted to 1 frame empty clips. Also, if you change the frame rate Premiere will have to interpolate the cuts and this can be really inaccurate leaving you with clips from all the wrong parts of your source footage.

5) Look out for avisynth crashes. If avisynth crashes it produces a short error clip instead of the footage. This is bad because it means the frames that were once there are no longer there. Premiere will sometimes, seeing that the frames are not there, convert your timeline edits to 1 frame completely destroying your project. The trick to avoid this is to NOT SAVE if you see this happen. Close down premiere, check your avisynth scripts to see if they are working, check your memory max settings and try the project again. If it's been saved with 1 frame cuts then you will have to go back to an older save file to restore your project. This is why setting up a Project Archive is important - you can see how to do that in the section on setting up your Premiere Project.

If you keep these things in mind you will discover that using avs footage is a mostly painless procedure. If you have any difficulties you should see the testing phase earlier in the guide for details of possible avisynth problems. If you have any concerns or questions, ask in the Video Software forum.

Now that you've read the info and understand the issues it's time to see how to correctly set up your video project.

Frameserving Avisynth to Programs without .avs Support

This method uses what is known as an avi wrapper. Many programs, when you give them a file, expect it to have a header that they recognise just like an avi header or an mpeg header. AVS files, however, are just text files so they do not have the information many programs need.

There is a way around this using the newer builds of FFDShow, as contained in the AMVapp. When installing FFDShow you can select to enable Avisynth scripts serving. With this setting chosen you can then go to your FFDShow folder in your start menu and choose FFDShow > MakeAVIS to bring up the makeAVIS gui.
MakeAVIS gui
The makeAVIS gui is pretty straightforward. It is possible that different options will be required for different programs but most of the time the following procedure will work fine:

1) Make sure your avisynth script outputs RGB32 as that will be what most programs will want.

2) Don't try and serve audio unless you really need to - it's a little buggy. Compressed audio is especially troublesome.

3) Don't use the 'Force' options (luke) unless things really aren't working for you in your program.

Import your avs file, set the options then choose create to make a tiny .avi file - this avi file doesn't contain any real content it just makes the program thinks it does as all the frames are generated by avisynth on-the-fly. This avi file can be used in any program that reads avi files. However, you cannot delete your avs file, nor should you change any of the settings in it without making a new .avi file.

This method for using Avisynth scripts should work as well as the Premiere method but it has not been tested as thoroughly, so proceed with caution. Like with Premiere there are certain things you need to be careful about when dealing with avisynth footage.

1) Check that the script works in VirtualDubMod. If you open a faulty script in Premiere you will just get a small 10 second clip containing an error message so you should test all scripts beforehand.

2) Make sure your avs script is creating an RGB32 output . Most editing programs process natively in RGB and it is best to give them footage in this format so you know that what you put in is what you will get out. You can do this by adding ConvertToRGB32() at the end of your script.

3) Don't slow down clips too much. Avisynth has been known to crash in Premiere when you do this so it is also likely in other programs too. Either make a still and use that or if it crashes when applying lots of filters, try and pre-render the section with a lossless codec.

4) Do not change your script. The makeAVIS program creates an avi header based on the script info at the time, it cannot change this if you change your script and so it could cause crashes or bad footage.

5) Look out for avisynth crashes. Avisynth has a tendancy to crash if a) the script has a bad filter chain or b) there are memory buffer issues. The former should be spotted in VirtualDubMod once the script works it should be left alone. The latter can be fixed by editing the "setmemorymax.avsi" file contained in your Avisynth 2.5/Plugins folder. The amvapp includes this script and sets the default to 64mb which means 64mb of memory is allowed per script used. You can reduce this as you please to avoid memory issues but don't make it too low.
It is possible that the makeAVIS method may have a larger memory overhead than the Premiere import method, so make sure you keep an eye on memory useage when doing exports to avoid crashes and don't use too many avisynth scripts unless you really have to.

Now you have your fake avi files ready, you can set up your video project.

AbsoluteDestiny - January 2003