HD Archive Settings

discburn wrote on 6/3/2019, 12:57 AM

I'm in the process of archiving a 720p29.97 project that worked our very well, indeed with the assistance of this forum.

To keep the original footage involves storage of 70GB.

I've exported my timeline using the MPEG export HDV1 Camcorder (NTSC, 1280x720p) preset. The bitrate is a constant 18,300 kBits/s. Because the original footage is HDV1 NTSC, this output gives a much better picture, where fine detail is present, than the MPEG 4 export preset.

So, rather than keep all the original footage, I'm thinking of using my HDV1 export as my 'Master', ie I can bring it back onto my timeline for re-editing, burning a DVD, etc.

However, I see on the MPEG export page another option - HD Archive 1280x720p NTSC. On examination of the output details, I see the Frame rate is 59.94 and the bitrate is variable from 28,000 kBit/s to 73,840 kBit/s.

I could change the frame rate to 29.97. But perhaps, then, the bitrate is too high?

Also, will the quality be any better than my HDV1 version? I have done small export tests and I'm not sure if the image is any better.

All comments appreciated!

Seamus

Comments

johnebaker wrote on 6/3/2019, 3:28 AM

@discburn

Hi Seamus

. . . . Frame rate is 59.94 and the bitrate is variable from 28,000 kBit/s to 73,840 kBit/s . . . .

That maximum frame rate is very odd when you compare it to the PAL version of the same preset, with a max of 28000 - granted there is a 20% increase in fps however this does not equate to ~ 2.6x bitrate requirement.

Personally I would set the maximum bitrate to 36000 for 50 fps, or, if you change it to 29.97fps, then I would set it to 28000 and save the settings as a new Export preset.

HTH

John EB

discburn wrote on 6/3/2019, 3:45 AM

@johnebaker

Hi John EB,

.... if you change it to 29.97fps, then I would set it to 28000 and save the settings as a new Export preset....

On the 'Video settings' page, the 'Medium value (kBit's)' is 28000. Should I set the Maximum to just a little above 28000? Or stick with 28000 and set 'Bitrate mode' to Constant?

And, will the exported file be a better quality master than the HDV1 export at 18300 kBit/s? (given that the source material is HDV1 at 183000 kBit/s, albeit edited, colour corrected, etc.)

Seamus

johnebaker wrote on 6/3/2019, 4:37 AM

@discburn

Hi Seamus

I see you are using the MC codec, the info I was for the Intel (Default) codec, however looking at the MC settings they too are at odds with the equivalent PAL settings by the same amount as I previously quoted.

. . . . the 'Medium value (kBit's)' is 28000. Should I set the Maximum to just a little above 28000? Or stick with 28000 and set 'Bitrate mode' to Constant . . . .

I would suggest you set the maximum to 36000 to give the encoder some headroom - see below - and leave the Bitrate mode at variable - if you set it to constant then you are defeating the encoder's capability of using a higher value for fine detail and movement and lower where there is less detail or movement in the video.

I have found, after examining many exports with a Bitrate viewer for a different issue with MEP/VPX and DVD Architect, that despite setting a maximum bitrate this will be exceeded, if necessary, when using variable mode, this is desirable to maintain fine detail quality.

HTH

John EB

discburn wrote on 6/3/2019, 1:55 PM

Thanks John EB,

I changed the setting as you suggested: to Medium bitrate of 28000 and Max of 36000. Then I exported my 720p29.97 file. The export was quite fast.

I downloaded BitrateViewer (great little tool) and examined the result. Indeed, as you suggested, at 33mins 15secs, during a dissolve with fine detail, the bitrate was above the max of 36000. The average bitrate was around 29000.

However, it's hard, visually, to see if the HD Archive export is better than the 18300 bitrate of the HDV1 export.

Given that NTSC 1080p29.97 can be HD Archived at Medium 28000 to Max 48000, I expect 720p might only need Medium 20,000 to Max 32000 (.666 of the resolution)?

Also, in practice does HD Archive, with its higher export bit rates, 'technically' increase or preserve the quality of the timeline, regardless of if it 'looks' better or not?

Thanks in advance,

Seamus

johnebaker wrote on 6/4/2019, 2:54 AM

@discburn

Hi Seamus

. . . .However, it's hard, visually, to see if the HD Archive export is better than the 18300 bitrate of the HDV1 export . . . .

Very true - without the necessary analytical tools visual assessment is very subjective.

. . . . in practice does HD Archive, with its higher export bit rates, 'technically' increase or preserve the quality of the timeline . . . .

The higher export rates mean the fine detail and fast movement is preserved better, however, as you have found visually, it is difficult to see this. The improvements appears to follow the law of diminishing returns.

HTH

John EB

discburn wrote on 6/4/2019, 3:53 AM

@johnebaker

Thanks John EB,

So, just to make a definitive HD Archive Preset for 1280x720 29.97p, given that the settings for 1920x1080 29.97p are at Medium 28000 and Max 48000, what would the ideal Medium and Max settings for 720p be?

Seamus

johnebaker wrote on 6/4/2019, 4:25 AM

@discburn

Hi Seamus

. . . . Medium 28000 and Max 48000, what would the ideal Medium and Max settings for 720p . . . .

For 720p I would use the 720p HD Archive setting and change the, IMHO, excessive 73,840 Max to 36000.

HTH

John EB

discburn wrote on 6/4/2019, 4:39 AM

And you'd be happy with the Medium setting at 28000? In other words it's not too high?

Sorry I get a bit 'nutty' about exact settings! 😩
I remember some years ago, using a different encoder, I increased the MPEG 2 bitrate of an export above its 'normal'/'preset' setting, and the result was pixelation/blocking, etc. I was amazed and, I guess, traumatized! I've been overly careful ever since!!

Sorry for the bother!

Seamus

johnebaker wrote on 6/4/2019, 6:39 AM

@discburn

Hi Seamus

Quite happy.

. . . . I increased the MPEG 2 bitrate of an export above its 'normal'/'preset' setting, and the result was pixelation/blocking . . . .

That would suggest the playback device could not cope with the higher bitrate.

In the case of archiving you are preserving the best quality video for future use in video editing software.

HTH

John EB

discburn wrote on 6/4/2019, 6:58 AM

@johnebaker

Thanks John EB,

Comforting words!! I'll go ahead confidently now!

Seamus

browj2 wrote on 6/4/2019, 8:14 AM

@discburn

Hi Seamus,

70GB = 3 or 4 BR disks. I back up all of my source material (eventually) to BR. The cost is minimal. If you ever have to go back and edit the video, it will be to add something that you no longer have. Murphy's laws prevail.

John CB

discburn wrote on 6/4/2019, 8:42 AM

@browj2

Thanks John CB,

Yes, I have to weigh up that possibility too. I had thought of a DNxHD export, but that's a tricky business, and the file size would be very big anyway.

I'm coming from a music background, too, where I always mix down to a 24 bit master because you never know if future versions of your software will support all the effects types and settings you have meticulously put in place. And my projects are always at least 1 hour long!

I think my HD Archive will have everything I need. Pity the Smart Render didn't work for my original M2V files. That would have drastically reduced the backup size.

Anyway, forwards we go! 😤

Seamus