This should probably be in the DVD encoding section, but since I have a HD110, I wanted to address this specifically to other users.

I shoot HD 720P30, edit AIC in FCP. It looks gorgeous. When I make a QT movie out of FCP using the same settings, that looks gorgeous. But every time I try to downconvert the finshed piece to SD for DVD, it looks terrible. The graphics go soft and serious aliasing is introduced - and I don't ubnderstand since this is progressive footage. Is it the AIC intermediary codec that is messing me up? What do you guys find gives you the cleanest output to SD DVD using FCP and compressor?

This should probably be in the DVD encoding section, but since I have a HD110, I wanted to address this specifically to other users.

I shoot HD 720P30, edit AIC in FCP. It looks gorgeous. When I make a QT movie out of FCP using the same settings, that looks gorgeous. But every time I try to downconvert the finshed piece to SD for DVD, it looks terrible. The graphics go soft and serious aliasing is introduced - and I don't ubnderstand since this is progressive footage. Is it the AIC intermediary codec that is messing me up? What do you guys find gives you the cleanest output to SD DVD using FCP and compressor?

I output my timeline in QT format, then use Compressor "Best Quality 2-Pass" presets for video & Dolby 2.0 preset for Audio.

The way I understand it, all DVD compression codecs convert whatever you have to 480i wether it was originally progressive or not.

If there is in fact a way to keep it progressive, I would love to know how.
I know that DVD players are capable of outputing progressive for people with LCD/flatscreen displays but I think it's just using software to combine the 2 fields into a progressive stream.

Just my understanding. I could be wrong.

If you're editing 30p then your footage will "effectively" still be 30p even on a 60i DVD. Progressive displays will generally have fairly smart deinterlacers that can find the progressive picture in the interlaced stream and display that.

This should probably be in the DVD encoding section, but since I have a HD110, I wanted to address this specifically to other users.

I shoot HD 720P30, edit AIC in FCP. It looks gorgeous. When I make a QT movie out of FCP using the same settings, that looks gorgeous. But every time I try to downconvert the finshed piece to SD for DVD, it looks terrible. The graphics go soft and serious aliasing is introduced - and I don't ubnderstand since this is progressive footage. Is it the AIC intermediary codec that is messing me up? What do you guys find gives you the cleanest output to SD DVD using FCP and compressor?

I used to simply make a Quicktime movie and import that into DVD SP thinking it was ok. After I tried using Compresser and best quality 90 mins it is a remarkable difference in quality. It takes a while but I am really happy with the workflow. I am in Pal land but should still be the same.

While we are on the subject- how does one go about creating a 480p DVD? Everytime I burn a DVD originating from 720p60 I get a 480i DVD no matter what.

There's no such thing as a "480p DVD." Progressive scan isn't in the DVD standard. The standard is very tied to the NTSC and PAL standards in which it was intended to be viewed.

If you're downconverting 720p60 for DVD I would recommend 480i60 to maintain the temporal resolution of your source material.

There's no such thing as a "480p DVD." Progressive scan isn't in the DVD standard. The standard is very tied to the NTSC and PAL standards in which it was intended to be viewed.

If you're downconverting 720p60 for DVD I would recommend 480i60 to maintain the temporal resolution of your source material.
Actually 480p24 and 480p30 are in the DVD standard. I make progressive DVD's all the time.

Check this reference Click here (http://en.wikipedia.org/wiki/Display_resolution)

Actually 480p24 and 480p30 are in the DVD standard. I make progressive DVD's all the time.

Check this reference Click here (http://en.wikipedia.org/wiki/Display_resolution)

What does the Wikipedia article have to do with what we're talking about? Maybe you meant to link to the DVD-Video article but it doesn't explain the issue either.

DVD video is 60i. Period. Okay, 50i in PAL. But it's never progressive. When you click the "encode progressive" option or whatever in your authoring software, it's not storing progressive frames on the disc. It's storing fields and using flags to indicate that they used to be frames, and in the case of 24p it uses repeat flags on the fields that don't change due to the 3:2 pulldown. A smart DVD player can look at the flags and recreate the progressive frames. A dumb DVD player doesn't have to look at the flags, it just has to decode the fields and spit them out to the TV. That's how Joe Blow can buy a $37 DVD player at Wal-Mart.

If the frames were actually progressive on the disc a dumb DVD player would have to be made more sophisticated (read expensive) in order to apply pullup to progressive material. While the ability to store progressive material natively would be nice, the added hardware complexity required makes it unsuitable for a consumer format.

What does the Wikipedia article have to do with what we're talking about? Maybe you meant to link to the DVD-Video article but it doesn't explain the issue either.

DVD video is 60i. Period. Okay, 50i in PAL. But it's never progressive. When you click the "encode progressive" option or whatever in your authoring software, it's not storing progressive frames on the disc. It's storing fields and using flags to indicate that they used to be frames, and in the case of 24p it uses repeat flags on the fields that don't change due to the 3:2 pulldown. A smart DVD player can look at the flags and recreate the progressive frames. A dumb DVD player doesn't have to look at the flags, it just has to decode the fields and spit them out to the TV. That's how Joe Blow can buy a $37 DVD player at Wal-Mart.

If the frames were actually progressive on the disc a dumb DVD player would have to be made more sophisticated (read expensive) in order to apply pullup to progressive material. While the ability to store progressive material natively would be nice, the added hardware complexity required makes it unsuitable for a consumer format.
Are we going to get into this again? We went through this last year. There is DVD progressive. If the DVD player is connected via Y/C or Composite it will ouput interlace only. If the DVD player is connected Component it will ouput progressive to a progressive capable TV (ie flat panel).

S

If you could find a link to that thread I'd like to see it.

Just because a smart DVD player can produce progressive output doesn't make the format itself progressive. Deinterlacing video doesn't make the original video progressive. The video is stored on the disc as 60i and any processing done by the DVD player doesn't change that.

If you could find a link to that thread I'd like to see it.

Just because a smart DVD player can produce progressive output doesn't make the format itself progressive. Deinterlacing video doesn't make the original video progressive. The video is stored on the disc as 60i and any processing done by the DVD player doesn't change that.

This is all obfuscatorated. Is it perhaps like the Sony V1? where the stream is 60i but the video encoded within the 60i stream is truly progressive?

That is the progressive frames are imbedded into a 60i stream... then a cheap player just plays the 60i but a progressive player pulls the progressive frames out of the 60i stream and they are displayed as the original progressive frames.

???

This is all obfuscatorated. Is it perhaps like the Sony V1? where the stream is 60i but the video encoded within the 60i stream is truly progressive?

That is the progressive frames are imbedded into a 60i stream... then a cheap player just plays the 60i but a progressive player pulls the progressive frames out of the 60i stream and they are displayed as the original progressive frames.

???

That's exactly it. There are flags in the bitstream that indicate that certain pairs of fields were originally part of a single frame, and a smart DVD player can use those flags as hints to build progressive output. It was done this way precisely so that a cheap player could be as simple (cheap) as possible, while still allowing for more sophisticated players to produce progressive output painlessly.

It's also similar to how the HDxxx records 24p and 30p to tape when HDV is natively 60p. Repeat flags are used to duplicate frames without taking up more bandwidth.

Exactly. The basic video on a DVD Video is either 625/50 or 525/60, just like progressively scanned SD video is recorded to either 625/50 or 525/50. Metadata for handling that image within the DVD player for prog scan output via component is another matter.

Techies arguing is such a great opportunity to learn!
So, putting aside the semantics of the dispute, it would seem that:

•All dvd's have a 60i signal which is inherently "interlaced".
•Flags can be added to the encoding, allowing "smart" players to decode "true" progressive.

What I assume however, is that since 2 interlaced fields are still required to make a frame, 60p cannot be recreated. So 60p footage could be encoded for 30p playback (temporal loss, possible motion issues not seen at 60p), or 60i (temporal speed unchanged, less sharp on LCD/Plasma displays). Same effect with different numbers for 50p shooters.

Interesting (tough) choice for those of us in the HD200 series camp shooting 60p/50p, (or HD100 shooting SD 50/60p). For HD100 series owners (or other 24p/25p/30p sources), encoding "progressive flags" would appear to be a no brainer for HDV sources converted to SD for DVD.

I think this has been covered before, but one of the clear issues in keeping quality going to DVD from HDV is with quality re-sizing / downconverting prior to mpeg encoding. Search for exact workflows...

Stephen sez:
"It's also similar to how the HDxxx records 24p and 30p to tape when HDV is natively 60p. Repeat flags are used to duplicate frames without taking up more bandwidth."

Flags are definitely used to differentiate the 24/30p frames, but 6 frame GOP mpg2 HDV isn't "natively 60p" I believe. The camera is native 60p, but sends to tape 30p or 24p with 6 unused additional frames. Using a firestore with 24p actually discards those frames and uses less space. The 12 frame GOP of true 60p is natively 60p, and can be interpreted in post to other frame rates, although we don't have the flags that a varicam creates while recording, which allow preview of the effect.

Preparing for fireworks...

I can't find my source but I'm very sure I've read that the HDV used by the HD100 operates at 60fps and uses repeat flags on 24 and 30p material. Yeah, useful, I know.

720p60 downconversion for standard def is a no-brainer. 60i, not 30p. By going wtih 30p you're losing half your temporal resolution and making it look juddery. And I've mentioned before that going 30p will not result in any more vertical sharpness because 30p in standard def is treated exactly the same as 60i.

When you watch standard def TV (especially sports), often times you're looking at downconverted 720p60. I can't name a single broadcaster that chooses to maintain a progressive look in downconversion at the expense of temporal resolution. They all downconvert to 60i.

This article actual contradicts my previous understanding on this topic, so I hope everyone can forgive me if I've said anything misleading in the past. The following quote is from this URL:

http://www.hometheaterhifi.com/volume_7_4/dvd-benchmark-part-5-progressive-10-2000.html


How Progressive Players Work

How The Information is Stored on Disc

It’s important to understand at the outset that DVDs are designed for interlaced displays. There’s a persistent myth that DVDs are inherently progressive, and all a DVD player needs to do to display a progressive signal is to grab the progressive frames off the disc and show them. This is not exactly true. First of all, a significant amount of DVD content was never progressive to begin with. Anything shot with a typical video camera, which includes many concerts, most supplementary documentaries, and many TV shows, is inherently interlaced. (Some consumer digital video cameras can shoot in progressive mode, and a handful of TV programs are shot in progressive, particularly sports events.) By comparison, content that was originally shot on film, or with a progressive TV camera, or created in a computer, is progressive from the get-go. But even for such content, there is no requirement that it be stored on the DVD progressively.

DVDs are based on MPEG-2 encoding, which allows for either progressive or interlaced sequences. However, very few discs use progressive sequences, because the players are specifically designed for interlaced output. Interestingly, while the sequences (i.e., the films and videos) are seldom stored progressive, there's nothing wrong with using individual progressive frames in an interlaced sequence. This may sound like a semantic distinction, but it’s not. If the sequence is progressive, then all sorts of rules kick into place which ensure that the material stays progressive from start to finish. Whereas if the sequence is interlaced, then there are fewer rules and no requirement to use progressive frames. The encoder can mix and match interlaced fields and progressive frames as long as each second of MPEG-2 data contains 60 fields, no more, no less (or 50 fields per second for PAL discs). The progressive frames, when they are used, are purely for compression efficiency, but the video is still interlaced as far as the MPEG decoder is concerned.

The input to a DVD encoder (the instrumentation that is used to author a DVD) is almost always an interlaced digital master tape, even if the original material was shot on film. The video transfer is typically done at a different facility, and the output of the transfer is interlaced. Since the DVD encoding software doesn't even have access to a progressive master, it must rely on the same kinds of algorithms that a deinterlacer uses to put the proper fields together. Since there is essentially no requirement that it actually always put the proper fields together, other than compression efficiency, many encoders are conservative about using progressive frames. If the encoder cannot be sure that a frame is progressive, it will typically mark it interlaced, because the only real loss is a few bits of disc space.

When the mastering engineers view the disc for quality control, they view it on an interlaced monitor. They don't necessarily care how well it deinterlaces, because that's not part of the DVD spec. Some mastering houses do pay attention to the flags produced by their encoder, and some do view the disc on progressive players just for quality control, but that's not at all required.

In short, the content on a DVD is interlaced conceptually, and is stored in interlaced sequences. Frames can be marked "progressive" to help compression, but are not always marked that way, even when it would be correct to do so. In interlaced sequences, the encoder can either keep the fields separate, or combine them together into one frame, whichever is best for compression purposes. There is a flag on each image stored in the MPEG-2 stream called “picture_structure” that can be either “frame” for a full 720x480 pixel frame, or “top field” or “bottom field” for a single 720x240 field. (We’ll learn about top and bottom fields later.) And it is allowed, but again not required, to set a flag called “progressive_frame” as a hint to the decoder that the fields in that frame were taken from the same frame of film. This allows for better pause and slow motion modes, and better down-conversion of 16x9 images for 4x3 displays. But this is again, purely optional. The content will play fine whether the data is structured as fields or frames, and whether the flag is present or not.

In fact, the encoder is allowed to combine fields that are not from the same film frame together, as often that produces better compression, even for inherently interlaced video. In such cases, the encoder is not supposed to set the progressive_frame flag, but again, if it does happen to get set, it will make no difference for normal playback on an interlaced display. And since interlaced displays are the only thing DVD was designed for, sloppiness with flags is more common than you’d think.

The flags on the disc, and the structure of the frames, are purely hints. Interlaced video can be stored on the disc as frames, and progressive frames can be broken into fields. The progressive_frame flag can be there or not. It doesn’t make any difference for interlaced playback. As we will see, though, it can make a big difference for progressive playback.

I can't find my source but I'm very sure I've read that the HDV used by the HD100 operates at 60fps and uses repeat flags on 24 and 30p material. Yeah, useful, I know.

720p60 downconversion for standard def is a no-brainer. 60i, not 30p. By going wtih 30p you're losing half your temporal resolution and making it look juddery. And I've mentioned before that going 30p will not result in any more vertical sharpness because 30p in standard def is treated exactly the same as 60i.

When you watch standard def TV (especially sports), often times you're looking at downconverted 720p60. I can't name a single broadcaster that chooses to maintain a progressive look in downconversion at the expense of temporal resolution. They all downconvert to 60i.

Well if the HD100 recorded 60p, there's sure a lot of you guys out there who'd like to be using it! <gr> Also I was informed by JVC that although 24p takes the same time on a tape by tape design, on the firestore it uses less space, since less frames are recorded to the drive...

From 60p, 60i may very well be better for many things - certainly sports... but for material with more stately rhythms, viewed on progressive oriented equipment (LCD/Plasma "smart" dvd player, 30p, ensuring flagged progressive playback could have advantages over the "unflagged" 60i. Fields with slight differences (interlace artifact) would be created - although I realize that we are used to seeing these, they are a factor. 30p originated footage, WOULD be treated the same at 60i, since fields would originate from the same frame. But interlace is also known to compress less effeciently.

Progressive is inherently better for both acquisition and broadcasting, and part of why many of us chose this camera. The temporal resolution limitation is purposely chosen by many (ok often abused) witness the popularity of 24p settings with the panasonic DVX.

But bring on the darn blu-dvd's or hd-rays asap. I wish apple would put it's big posterior on the line and give us machines with the burners and software with the authoring. Like, this year!

Meanwhile progressive broadcast is also clearly the path for HD. In Europe they have this path clearly envisioned.
http://www.jvcpro.co.uk/getResource2/jvc_highway_4_ibc.pdf?id=6594
article "EBU backs emerging progressive standard"
60p HD broadcast, 720 now, 1080 to come. Leave interlace behind!

Well if the HD100 recorded 60p, there's sure a lot of you guys out there who'd like to be using it! <gr>

While the container stream is running at 60fps, the encoder in the HD100 isn't sophisticated enough to fit 60p into the bandwidth allotted to it, which is why it records 30p with repeat flags to fit in the 60p container.

I realize the encoder is the weak link here. But why waste bandwidth with 60 frames instead of 30?
I was just teasing about the frame envy issue...

BUT, the firestore taking up less drive space with 24fps than 30fps is the fact that makes this 60 frames stream with flags seem strange. I don't have a firestore, but I remember this clearly as an interesting and useful feature in the JVC presentation. Going to tape, they have the same size file.

This isn't a challenge, Stephen. I'm just curious to have a better understanding of this stuff!

The repeat flags don't take up any (well, hardly any) bandwidth at all. They just tell the decoder "play this frame twice."

Without more detailed knowledge of the HDV spec I couldn't say exactly why this is done. I know DVCPro HD can only do 60fps in 720p, and Varicam uses the same technique to record slower frame rates on tape. Maybe HDV is the same way.