Convert 720p60 to 480i

TeetimeNC wrote on 4/2/2011, 3:30 PM
In a separate thread here I was discussing converting 720p60 footage to 480i for DVD. I had understood that Vegas would convert each frame to a field in the 480i footage, but learned that instead Vegas drops every other frame resulting in essentially 480p30 in a 60i stream.

In searching the web I learned that FCP's Compressor does the conversion I thought I was getting. There is a YouTube tutorial for this at the bottom of this post. Is there a way I'm not aware of to achieve this using Vegas and perhaps other 3rd-party tools?

/jerry

Comments

NickHope wrote on 4/2/2011, 9:32 PM
I expect you can do this in AviSynth but I don't know exactly how. I would take your question here. You can open the output of AviSynth in VirtualDub for rendering, or you can open it in Vegas if you use VFAPIConv to turn it into a dummy AVI file first.
musicvid10 wrote on 4/2/2011, 9:36 PM
If I understand correctly, you want to convert each frame of a 60p source into a field in a 60i render, is that correct? I can foresee some possible jitter or blur from using divergent frames (rather than the same frame) as as upper and lower fields, but it is worth experimenting, perhaps in VDub . . .
corug7 wrote on 4/2/2011, 10:45 PM
There should be no problem with this. I do it all the time.

Start with a 720p 59.94 timeline or a 480i 29.97 timeline and drop the footage in. Make sure you choose a deinterlace method (I use interpolate to minimize any chance of ghosting) and render to an interlaced file. I just did it three different ways and all have the same result.

No need to go to VDub. Compressor does a slightly better job downscaling but not much. If you think your footage might not be exactly 59.94 disable resampling on the clip so that you don't get blended frames, because that would look pretty yucky on interlaced footage.

FWIW, I try to never shoot interlaced footage anymore. 60p, 30p, or 24p for me, because if I need it I can render to an interlaced file. Unfortunately that doesn't work so well with my FX1, but at work I use an EX3 and I have not yet shot in 1080i on a paying job with that camera. If it goes to interlaced DVD, I shoot 720p60.
craftech wrote on 4/3/2011, 5:11 AM
No need to go to VDub. Compressor does a slightly better job downscaling but not much.
==========================
Compressor? Do you mean this?

John
TeetimeNC wrote on 4/3/2011, 5:44 AM
>If I understand correctly, you want to convert each frame of a 60p source into a field in a 60i render, is that correct? I can foresee some possible jitter or blur from using divergent frames (rather than the same frame) as as upper and lower fields, but it is worth experimenting, perhaps in VDub . . .

musicvid, yes - you understand correctly - I want to convert each frame of a 60p into a field in a 60i render.

>There should be no problem with this. I do it all the time. Start with a 720p 59.94 timeline or a 480i 29.97 timeline and drop the footage in. Make sure you choose a deinterlace method (I use interpolate to minimize any chance of ghosting) and render to an interlaced file. I just did it three different ways and all have the same result.

corug7, I just tried this again and it is working for me. I'm not sure what I did wrong the first time, but thanks for your post which showed me it could be done. Question: why would it matter whether you choose interpolate or blend in the project setting since we are not actually deinterlacing? I know you need to choose one or the other to get Vegas to rescale properly, but don't see why it would matter which you choose.

Like you, I try to never shoot interlaced footage. Mostly I shoot 720p60 with my thinking being that it allows all the following from that source:

- render 720p30 for web
- render 720i60 for bluray
- render 480i60 for dvd
- conform to 24p and render smooth slow motion

I also shoot 24p when I want more of a film cadence. I want to experiment more with the 720p60 to 480i60 to see if I get any of the jitter or other problems. I'm also open to any comments about possible flaws in my strategy.

I do have one more question - is there a viewer that will let me view each field in my interlaced video that I converted from my 60p?

/jerry
PeterDuke wrote on 4/3/2011, 6:04 AM
"is there a viewer that will let me view each field in my interlaced video that I converted from my 60p?"

You can do it for an AVI file by using AVIsynth plus VirtualDub.

The AVIsynth script is:

clip=AVISource("filename.avi")
clip.SeparateFields

If the fields are in the wrong order, use instead for the second line:

clip.ComlementParity.SeparateFields

Put the script in a .txt file called say "clip.avs" and open that in vdub as though it were a video file.

The interlaced video becomes double frame rate but half height (squashed looking).

I suggest rendering your file to AVI using Lagarith lossless encoder.
craftech wrote on 4/3/2011, 6:15 AM
Jerry,

Read through This Thread.

You may find it helpful.

John
corug7 wrote on 4/3/2011, 7:39 AM
Craftech, I was referring to Apple's Compressor, their transcoding software in the FCP suite.
craftech wrote on 4/3/2011, 7:53 AM
OK,

Didn't realize you also use FCP.

John
TeetimeNC wrote on 4/3/2011, 1:20 PM
I figured I would try rendering some 720p60 to 720i60 using the Sony AVC Blu-ray 1280x720-60i, 16 Mbps video stream template. I get "An error occurred while creating the media file test.avc. The reason for the error could not be determined." I'm using 10c and get the same error on either the 32 or 64 bit version. I also tried generated media instead of my footage - same error. Has anyone been able to render using this template?

/jerry
TeetimeNC wrote on 4/3/2011, 1:22 PM
>You may find it helpful.

Thanks John - that WAS helpful. I downloaded the plugin and installed it.

/jerry

corug7 wrote on 4/3/2011, 4:24 PM
Teetime,
I don't believe 720i exists as a standard. For bluray use 720p59.94.
TeetimeNC wrote on 4/3/2011, 8:06 PM
>I don't believe 720i exists as a standard. For bluray use 720p59.94.

corug7, I think you are right - I must have made that template myself (for what - I don't know). I've looked at the AVC and MPEG2 templates and none permit 59.94. I can render AVI using HD 720-60p, Sony YUV codec, and DVDA seems to accept it. Is this what you would use? I would prefer to use AVC if there is a way to make it work.

/jerry
corug7 wrote on 4/4/2011, 8:19 PM
Jerry,

DVDA is very picky about what it will accept for Blu-ray. I have not yet been able to export a 720p59.94 AVC file that it will pass through without reencoding. I'll try a few more tests when I get back from vacation.
TeetimeNC wrote on 4/5/2011, 6:08 AM
Thanks corug7. I tried various settings and still couldn't get DVDA to accept 720p59.94 without reencoding. A while back I submitted a suggestion to SCS that DVDA should tell you what specific properties required the reencoding. They liked the idea but obviously haven't implemented it yet. I think I will submit a ticket with my settings and see if they have any suggestions. I'll post if I learn anything.

/jerry
TeetimeNC wrote on 4/7/2011, 4:14 AM
Now I learn on a different forum that SCS has implemented the suggestion to show why a recompress is required. However, as you can see in the screen shot below, the message in my particular case isn't very useful.

/jerry