Wednesday, December 24, 2008

Mastering 24p DVDs from HD using Premiere Pro.

24p DVD mastering.

First some basics, there is no true 24p mode on standard DVD, there are is only 60i encoding (and 50i for PAL.)  So all those film source are encode to DVD by adding 3:2 pulldown (or 2:2 for PAL with a 4% speed up for 24p sources.)  How this pulldown is added impacts how well your DVD presents on today's common progressive displays. 

Adding 3:2 pulldown for NTSC DVD creation has been has been tricky, seemingly there are lots of dead ends (like using Encore to encode directly to 24p -- this should work, I have made several blurry DVDs trying to use it.)  This is one of the most common support questions.  McCarthyTech has a good blog post on using AE to manually insert pulldown before encoding as 60i, and this will work everytime.  It was his post that has prompted this one, as there is an even simpler way using Premiere CS3+ directly, and if you are careful it can be even better for final presentation.  McCarthyTech's technique can be improved if we trust the MPEG2 encoder can to add the pulldown using repeat flags.  Fortunately this works correctly using the 23.976p encode mode within Premiere's Adobe Media Encoder (MPEG2-DVD preset), now we just have to watch out for other Premiere limitations.  

The advantage of pulldown that uses the MPEG2's repeat flags, this can help with quality as only fields used to construct the 24p signal are compressed, the repeat flag pad the data out to 60i. This flags also help progressive scan DVD players reconstruct the correct 24p signal more reliably. The manually created pulldown in AE works for most situations as many DVD players can use the data-rate pattern to guess the pulldown, but it is not always extracted correctly (seen as a weave pattern during motion.)  Of course there is no issue for non-progressive outputs where the display is reasonable for pulldown detection (if needed.)

The way I produced several 24p DVDs in the last weeks is to export out of Premiere as a 1920×1080 24p (23.976) master CineForm AVI, then I used VirtualDub and scale using Lanzcos 3 filter to 720×480 and export out to CineForm 444 SD.  Load the SD clip back into Premiere SD 24p preset, interpret footage back to 16×9, and export with Adobe Media Encoder to MPEG2-DVD 24p. Encore will take this file without further transcoding.  Now that seems to be an odd path and it is, plus using VirtualDub is unnecessary, but the export to 1920x1080 master first is a very important step. 

I first made the mistake of exporting my 1080p timeline directly to MPEG2-DVD, and it looks horrible.  I've made this mistake before, as you simply expect it to work (never has in Premiere up to the tested PPro v3.2), but here why it doesn't always do what you want.  When you add any spatial distorting filter (motion, blurs and sharpens, etc), you see the results previewed at 1080p, any scaling for your preview display is applied after the filter operations -- so you adjust you filter so they look correct on a 1080p source.   We you use the Adobe Media Encoder, the scaling is applied first, before any of your filters -- as a result your output doesn't look like you previewed -- spatial filter are around 2.5 times stronger than you intended.   In one of my recent projects, I was using the additional resolution of the 1080p source to reframe for a nicer DVD output, see below how much it matters in what order of operations that scale occurs (see below.)

The image on the left is soft and badly aliased, and it looks far worse in motion.  Simply exporting the timeline to 1080p first, then using that new file to export to DVD solves the problem, without ever leaving Premiere.  The VirtualDub step in my above technique can be as simply skipped, as loading the exported 1080p AVI into Premiere will use the CineForm importer's own Lanzcos 3 scaler for exactly the same results, much faster and more convient.  

Friday, December 12, 2008

What, no more Aspect HD?

After 5 years we are now retiring Aspect HD, and I say Yah!!!! David Taylor, CineForm's CEO, has post as to why on, but I like this change as we no longer need to remove key features from Prospect HD to make Aspect HD (that is how it is built.) This will streamline development and testing, plus slicing off all the really good stuff always bothered me. We will still have entry level products in the NEO line (more news to come,) but today's customers are increasingly purchasing their first CineForm product at the Prospect HD level (some going directly to P4K as Red users really need a workflow.) Recently Aspect was falling into no man's land, too pricey for the hobbiest and too feature limited for many professionals. The Prospect product line now starts at $749, lowering the entry point for professionals and existing Aspect users can product jump for $199 (only around $50 more than typical upgrade between AHD versions.) This upgrade will also include the upcoming CS4 version of PHD.

Aspect and Prospect a short History.

5+ years ago when Aspect HD was first released it retailed $1199, it was the only HDV professional product of its day for post. The only HDV camera at the time was the barely HD single chip 720p JVC HD10U, so Aspect HD took in only one camera format, 720p HDV and converted into an 8-bit AVI for much easier post within Premiere 6.5 (wow, we come so far since then.) Aspect HD was upgraded to Premiere Pro 1.0 and we soon added 1080i support as Sony FX1/Z1U was coming (we have a bread-boarded prototype of the Z1 in box at the office -- somewhere.) Then HDV exploded, many great cameras, and CineForm implemented the first HDV support for Adobe into Premiere 1.5.1, and Aspect HD prices fell and the sales volumes grew. Around the same time a Prospect HD beta version was used in the post of Dust to Glory, the first film sourced (and HDCAM, DV, etc.) theatrical release ever to have had an compressed online DI workflow. Support for more and more cameras where added, XDCAM-HD, P2, AVCHD, etc. While Aspect was growing beyond it HDV roots (bumping up against it 1440x1080 8-bit limits,) and Prospect was turning in the swiss army knife for all input types with the addition of DPX sequences, XDCAM-EX, Grass Valley Infinity, SI-2K, Red, Dalsa, Phantom all with HDSDI I/O. Over the years of Prospect, feature additions includes 10-bit, 12-bit, 4:4:4, alpha channels, RAW compression, Active Metadata and much more.  So today the Prospect line fits the role for today's indie professional, with so many input formats and many possible output types, it is nice to have an intermediate that handle yours resolution, bit-depth needs in real-time, without breaking the budget, your disk system, or the PC your are try run on. Aspect HD was being left behind when compared to Prospect, so I hope many Aspect users will make the jump to Prospect, as it is a big step up.

Bits of Fun

Here are a couple of videos internally created by CineForm engineers (plus friends) just for fun. The first is this year's entry to the 48 Hour Film Project. We drew the tough genre of "Holiday Film", so it is now seasonally appropriate (we created this one back in August.)

Competition requirements: a "Holiday Film" to be written, shoot, edited and delivered within 48 hours with these elements:
1) Character: Joe or Josie Beeble -- Construction Worker
2) Prop: Tweezers
3) Line of Dialog: Hey, have you heard the news?

The second is currently a finalist on, which is a competition entry to help one of our engineers win an Audi S4. The entry is called Visceral Thirst, so please vote for Tim (he said I can have a drive if he wins.)

Both films where shot using an SI-2K Mini, although Tim used some Sony V1U footage (all the beautiful car shoots in Visceral Thirst are SI-2K,) and both where finished in tight time-frames using Prospect 4K and Active Metadata.