Anyone who has edited HD footage and has had to output to an SD DVD is well aware of the shortcomings of today’s NLEs. Whether you are using Adobe Premiere or Apple Final Cut Pro, when you export your HD footage to MPEG2 DVD, the results are very poor. In fact, you might be thinking to yourself that it would look better had it been recorded in SD to begin with. Well you would be correct. The problem with current editing software is that they use very bad downscaling algorithms, the math that is used to convert a higher resolution source to a lower resolution output, leaving you with footage that is almost unusable. In this article, I will primarily focus on Premiere and the PC, as I still haven’t found an equally good alternative on the Mac. Final Cut users, please read the update at the bottom of the article.
Why both companies release their software year after year without offering the ability to export a high quality mpeg2-dvd file continues to go unanswered. As an example, here are some screenshots comparing HDV 60i footage, shot on a Canon XH-A1, that was downscaled using Adobe Premiere CS4 (through the Adobe Media Encoder) versus the same footage that was edited in Premiere and downscaled using a 3rd party application:
Your footage comes out looking very low resolution using the Adobe Media Encoder’s downscaling, especially noticeable on titles.
Adobe has recently made some attempt to offer an option to have better quality rendering. In CS4, they have added an option to the Sequence Properties to enable “Maximum Render Quality” aka MRQ. With this little box checked off, your Adobe Media Encoder will take FOREVER to render, and here are the results:
As you can see, the results are much better than before, however there is noticeably more artifacts and strong ringing around high contrast areas. It looks as if the text has a black stroke effect applied. Lets not forget, it took the Adobe Media Encoder horribly long to render this out, where as our 3rd party application (which I will get into later) takes far less time and looks better!
If you are satisfied with the results of the Maximum Render Quality image and don’t care if it takes 5x – 10x longer to render, then you can stop here. For those of you who care about achieving the best quality downconversion using completely free utilities… keep on reading.
Before we go any further, I would like to give credit to Dan Isaacs who has devoted so much of his time to perfecting a downscaling workflow and offer his knowledge to the community, frequently posting in the Adobe user-to-user forums. He does have a tutorial on his website, however it is a little outdated and his most recent improvements in the workflow are found by scouring through posts in the Adobe forums. I will be going over his methods and offering some additional suggestions when possible.
At first you may feel a little overwhelmed by all the steps involved and programs you will need to download, but I assure you, the process goes quickly and the results are spectacular.
The basic steps of the workflow involve:
- Exporting your Video out of Premiere
- Downscaling and applying other filters to enhance the image
- Encoding to mpeg2
Lets go through each step at a time so you get a better understanding of why we do each process and why there are so many additional tools you must download.
Exporting out of Premiere:
The ideal way would be to have Premiere deliver it’s frames directly to a second application without compressing, altering it, or exporting a huge file. This was easily done in Premiere CS3 using the Debugmode Frameserver plugin. Unfortunately since Adobe has shifted all the exporting to the Adobe Media Encoder in CS4, frameserving is not currently possible. So we must export in a format that is near lossless, renders quickly, and doesn’t take up too much space. There is one format that pretty much meets all those requirements, and that is MPEG2 I-frame. If you have a Matrox editing card, go ahead and export using the Matrox MPEG2 I-frame codec at 100 Mbits/sec. If you don’t have the Matrox codec, you can still configure the Adobe Media Encoder to export to MPEG2 I-frame.
The output settings for MPEG2 can be overwhelming if you are unfamiliar with all it’s terms. I highly recommend you download these:
Once you download and extract them to any folder, simply select MPEG2 as the output format in AME, click the icon to import a preset, then select the downloaded preset which matches your source footage.
Downscaling & Processing:
Once you have exported your HD master out of Premiere, its now time to apply advanced algorithms to the footage which will scale it down and do all kinds of optimizations for dvd playback. The free program you must download to do this is:
The program basically works like this; you create a script (commands in a text document) in the same location as your HD master export, which tells AVISynth what file to load and what effects/filters you want applied to it. AVISynth does not actually export your file, but rather does all the processing of the effects and filters, and delivers those processed frames to another application. Unfortunately Encore is not capable of importing the .avs file that the program generates, however many other programs and mpeg encoders are, such as Procoder, HC Encoder, and Virtual Dub among many others.
Dan Isaacs has provided a plugin/preset he created for AVISynth that does just about everything for you. Download it here:
Instructions for how to use his conversion package are included in the zip file. No additional plugins for AVISynth are required, since Dan has provided all of them for you in the zip file. Please take the time to read through his documentation. It explains all the different settings and how to tweak them, in addition to how to configure it for different footage types such as 24p, 30p, PAL, NTSC, 4×3, 16×9, etc.
If you think all of this is starting to go over your head, its really not that difficult, especially if you have HD 60i source footage, your script will probably consist of just this:
Now that your script is done, it might be ready to import into your mpeg encoder. If you will be using Encore to encode your mpeg2 file, you must create an AVI file that can be imported into the program. Having encore encode the mpeg2 file won’t look that bad since the quality issues mainly came from the downscaling which has already been done. The program you will need to install in order to open the AVISynth script and save as an AVI is called:
By default Virtual Dub will export an uncompressed AVI file, which takes up huge amounts of space. I highly recommend downloading and installing the free:
Once you install the codec and Virtual Dub, follow these instructions:
- Run VirtualDub
- Open your .avs script file in VirtualDub
- In VirtualDub, go to Video : Compression and select the Lagarith lossless codec
- Also set VirtualDub to use Video : Fast recompress mode
- Save your output to lagarith.avi
- Import lagarith.avi into Encore for transcoding and authoring
Encoding to MPEG2:
If you will be using Encore to encode, you should know where to go from here. I would suggest VBR 2-Pass encoding for best results, with a max bitrate of 8 Mbits, target of 7 Mbits, and minimum of 2 Mbits. You may need to adjust the target bitrate depending on how much content you need to fit on the disc.
If you want near studio quality mpeg encoding using a free program, I recommend downloading and installing HC Encoder which delivers extremely high quality results. A high quality mpeg encoder will produce slightly better looking video at greatly reduced bitrates, causing the file sizes to be much lower (did you ever wonder how hollywood movies are able to fit so much high quality video content on a single dvd? Its from using a good encoder).
There sure are a lot of steps to get a quality downconversion out of Premiere. Once you go through the entire process one time and get all the programs you need, you will realize it’s not that complicated and moves along quite quickly.
One of the drawbacks to this method is that you cannot export chapter markers out of Premiere. You can always create them in Encore, or you can render out a draft quality mpeg2 file from Premiere with chapter markers intact, import that into Encore, then replace the asset with the high quality version and your chapter markers will remain.
I look forward to the day when Adobe offers some good quality downconversions. But until then… this is one of the best methods to use.
UPDATE: Apparently the latest version of Apple Compressor (3.5) is producing even worse downconversion results than the previous version (3.05). However, after comparing both versions, even with the best quality resize setting applied under the frame controls, the results are still extremely poor compared to using AVISynth and the hd2sd script.
Final Cut Users: Export a contained Pro Res 422 HD quicktime out of Final Cut, load it onto a windows system, and use the method above starting with the “Downscaling and Processing”. Your Pro Res file will be loaded by the script without issues.
UPDATE 2: For those of you interested in following this topic on the Adobe forums, where Dan Isaacs and Jeff Bellune are posting responses and even more helpful details to this workflow and process, please read this thread.
UPDATE 3: Jeff Bellune has recorded a nice video tutorial of this workflow that can be seen here. I highly recommend watching it if you were confused in any way by this article.
UPDATE 4: There has been a good deal of discussion in forums about CS5 having greatly improved downscaling quality, and some believe the method outlined in this article is no longer necessary. It is true that the downscaling quality has greatly improved only when using the Mercury Playback Engine (read this post), however, it’s quality is still inferior to the hd2sd script. For many, the results of the improved downscaling of CS5 with Mercury Playback enabled may be good enough (and not require as many steps). But for those who demand the absolute best quality achievable, the hd2sd script should still be used.