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DVDs actually store only interlaced material. There are flags embedded in the stream that tell the MPEG decoder how to handle the fields, whether progressive or interlaced. Interlaced only players will simply ignore those flags and output an interlaced signal.
In short, your DVD should work fine with any player. The picture quality may well vary, but the disk itself should load and play without issue.
However, (1) if "DVDs actually store only interlaced material" why do they need flags? Flags suggest the DVD may contain Progressive stuff. Also (2) if an interlaced player outputs only interlaced video does it convert any progessive video?
Actually, this DVD was a test in which I compared an M2V exported with default settings from Premiere with an M2V exported with only Flicker removal set, one using the Anti-flicker filter and an M2V exported as Progressive (Field order). All 4 files were placed on the same timeline in Encore and burnt to DVD. When played on TV there was flicker only in the first two!
I just checked the file characteristics in Gspot. The M2V file exported from Premiere CS3 with Field order 'None' set was Progressive, the other m2vs are Interlaced. Also, the VOB from Encore CS3 containing all m2vs was read as interlaced!!!?
Looks as if Encore set a flag for the first M2V on the Timeline (interlaced) and did nothing else?! Then, Gspot simply read the flag!?
As a further check I placed only the progressive m2v on Encore's timeline: it did no transcoding, Gspot indicated 'PROG' for the main VOB (indicated interlaced for the menu VOB) and the DVD played on TV (player upscales and outputs progressive) with no flicker.
If a progressive video created in this way will play in any player the use of 'None' for the feld order is therefore the ideal way of overcoming flicker for Stills (photos, slides, etc)!
>if "DVDs actually store only interlaced material" why do they need flags?
To tell Progressive Scan players how to recreate the progressive signal from the stored interlaced signal.
>if an interlaced player outputs only interlaced video does it convert any progessive video?
Interlaced players simply ignore the flags and output the interlaced signal stored on the disk.
>Interlaced players simply ignore the flags and output the interlaced signal stored on the disk.
In that case, what happens if there is no interlaced video, only Progressive (as shown above, I had been able to place prog stuff on DVD)?
> DVDs actually store only interlaced material.
Haven't we been through this before, Jim? When you encode 24p there are 20% less encoded frames in the MPEG-2 stream. Therefore, it is "stored" as progressive. In this case, flags are added to tell interlaced hardware how pulldown should be added to achieve interlaced playback. Ideally, progressive hardware will ignore the pulldown flags completely -- or it may use them to repeat frames (not fields) to match 60Hz.
In the case of PAL Film (25p), there are no pulldown flags. There may be progressive flags on each frame, but this is only to tell the decoder that chroma information information is encoded as progressive (for YV12 colorspace, such as DVD, there is a big difference -- and this would apply to all playback hardware).
I have heard of issues with 25p or 30p material with older DVD players but I have never witnessed such problems myself. I have an NAD DVD player (about 8 years old) that played PAL 25p or NTSC 30p discs with no issues.
In practice, however, most PAL DVDs I've seen are encoded as interlaced even if the source is progressive (to get around any possible compatibility issues). To my knowledge, such a format cannot be output by AME unless you have a fully progressive source and choose Upper or Lower order from the menu.
If you'd like to achieve this in AME, Robin, you can:
1.) export your timeline as a progressive AVI (I suggest a lossless format)
2.) create a new PAL DV project
3.) import the AVI from step 1
4.) output via AME to DVD using upper or lower (does not matter) field order.
Thanks Jim and Dan for the comments.
They help, but, they also add to my confusion a little. For example:
> such a format cannot be output by AME unless you have a fully progressive source and choose Upper or Lower order from the menu
Assuming AME means Adobe Media Encoder, I do not understand this comment because, I've been exporting as Progressive with AME by setting Field order = none. This claim by Premiere's Help is confirmed by Gspot which saw the resultant M2V file as Progressive and by the fact that Encore did no transcoding when burning to DVD.
Also, there were other issues I had raised that still need addressing. As result I have done some more experiments.
1) With scanned slides and photos in Premiere CS3 and exported as Progressive scan M2V (Gspot & Encore agrees -- see above), I burnt it to DVD from Encore CS3. In a progressive DVD player (Pioneer DV-400) there was no flicker on the plasma TV.
2) This DVD played successfully in my older interlaced-player (DV-355), which had to convert it to interlaced before outut (added a little flicker and moved the subtitles).
3) When using the Anti-flicker filter to remove flicker, the export (Field order = lower, the default) was interlaced and on DVD it played much the same in either DVD player. There was no flicker but there was an obvious blur compared to the progressive output.
Based on comments from Jim and Dan, I have concluded that in my case the best way to overcome Flicker is to export from Premiere as Progressive (Field order = None). This is far simpler (one click) than the use of the Anti-flicker filter (needs adding and adjusting for each image). Also, unlike the Anti-flicker filter, it maintains image quality.
If I lend the (progressive) DVD to someone having only an interlaced-DVD player, all I need do is apologise for the slight flicker that may be introduced when their player converts to interlaced output.
>what happens if there is no interlaced video, only Progressive
It is still stored on the disk as interlaced, with the flags to tell progressive players how to rebuild it.
>Therefore, it is "stored" as progressive.
The DVD spec calls for storing only interlaced video. It would make sense that 24fps uses less space than 30fps, but that's a separate issue.
"There's enormous confusion about whether DVD video is progressive or interlaced. Here's the one true answer: Progressive-source video (such as from film) is usually encoded on DVD as interlaced field pairs that can be reinterleaved by a progressive player to recreate the original progressive video."
That quote is incorrect... Or, if is correct, then it's correct only some obscure technical sense that has no releation to how sources are prepared, encoded or authored.
> 24fps uses less space than 30fps, but that's a separate issue
Jim, you seem to have locked yourself into the case of a progressive source such as Film, which traditionally had been converted to interlaced when placed on DVD!
There are other situations, such as intentionally outputting material from Premiere Pro as Progressive scan, and feeding the DVD to a progressive player. The output is progressive: it is claimed by Adobe and may be deduced from the fact that there is no flicker on Stills (there is if exported as interlaced), it remains as progressive on passing through Encore (no transcoding), it is seen as such by Gspot and on playing in an interlaced-DVD player, it is changed (converted to interlaced). This I deduce because it added flicker, had moved subtitles and changed the brightness.
Hope my deductions are not wrong!
>it's correct only some obscure technical sense that has no releation
The relation is that even though Robin is exporting progressive content from Premiere, the disks created with such content will still work fine on interlaced only players.
> because the signal stored on the disk is technically "interalced"
OK. How does one produce progressive media, encode in as progressive, burn it to disc and have it magically become "interlaced"? How does this occur? I really do not understand this logic at all.
I cannot understand how/why the MPEG-2 specs would contain an optional progressive_sequence header and support per-frame progressive flags to handle hybrid material.
I cannot understand how/why pulldown flags would be required for 24p content if it were already stored as "interlaced".
If what Dan (and Jim, earlier) claims is true - that DVD specs include flags, etc, to cover progressive material, they mnust also allow such material to be present on DVDs.
Regardless of what DVD specs state, I have placed Progressive material on DVD, and that it is treated differently than interlaced video. For example, on the same DVD I have placed 3 titles: (1) interlaced video containing flicker, (2) interlaced with flicker removed (anti-flicker filter) and (3) progressive video of the same material but not having any flicker just because it is progressive!
In a Progressive-player, all titles play correctly, with no flicker evident for Titles 2 and 3. In the interlaced-player, only the two interlaced Titles play as above. The progressive Title behaves differently: it has flicker and the brightness had changed, etc.
If Title 3 had been changed to interlaced as it was placed onto DVD, it would have played the same on both players!!!