ffmpeg help - 16:9 HD -> 4:3 SD

[zehd]

It will be another couple of hours before I can download the sample.

Let me be clear. The sample is 4x3 inside a 16x9 rectangle (pillar box).

You want to convert dvr-ms to mpg (preferably an mpg appropriate for the MVP) and your want the vertical bars cut out?

I know you have the math worked out for the cropping. I'll probably steal that...

Give me some time. we'll see what I come up with

[Braklet]

Let me be clear. The sample is 4x3 inside a 16x9 rectangle (pillar box).

That is my eventual goal. The sample I am using (and made available to you) is NOT pillar boxed! I am simply using a minute of generic widescreen HD for testing.

Sunday night is the Simpsons season premiere and that is when I'll really need the HD -> SD conversion. Now that I have a basic ffmpeg command line in order I am just waiting for Sunday to put the final touches on this conversion.

You want to convert dvr-ms to mpg (preferably an mpg appropriate for the MVP) and your want the vertical bars cut out?

Pillar box cut out, final format 4:3 and appropriate for burning to DVD Video (4:3 video in a 720x480 window seems fine). I also plan to down-code it to approximately 4Mbps.

I know you have the math worked out for the cropping. I'll probably steal that...

It was a first guess only and I plan to test it when I have a real 4:3 sample to play with. Mathematically "-cropleft 160 -cropright 160" makes more sense.

Give me some time. we'll see what I come up with

I'm in no hurry, now that I have a better idea how to use ffmpeg.exe.

Thanks loads, Zehd!

[zehd]

That is my eventual goal. The sample I am using (and made available to you) is NOT pillar boxed! I am simply using a minute of generic widescreen HD for testing.

I guess it doesn't matter if it's pillar boxed. It would have been better to get a sample that was, to test. Certainly waiting for Sunday is leaving it to the last minute...

All you want is Center Cut. Chop off the wings. You're right that 160 on both sides makes more sense, as 540x480 is a pretty good estimate of a 4x3 inside 720x480 WITH the 16:9 flag set.

(Remember you can have 720x480 4x3 TV and 720x480 16:9 TV. I found out the hard way, that the pixels across and down, do not require to mathematically equate to an aspect ratio...)

Just downloading the file now. Kinda slow, but that's probably limited to your upload speed, as most folks are. Much better than two tin cans and a string though...

I'll be looking at it this evening.

[zehd]

Progress report.

It's gonna work.

Really Well.

[zaphod7501]

VideoReDo now offers DVD authoring in a beta version (if you are a registered user). One of the things it can do is take HD content (720p, 1080i) and transcode to 720x480 as part of the editing and authoring processes. It uses hcenc rather than ffmpeg and VBR not CBR.

I have not experimented with the feature myself yet but there are numerous settings to correct aspect ratios, etc. Obviously still in beta but if creating a standard DVD from HD material, it might be the choice to edit, transcode, author, and burn within a single application.

http://www.videoredo.net/msgBoard/showthread.php?t=5041
http://www.videoredo.net/msgBoard/showthread.php?t=5063

[dgeezer]

This thread contains the script command for videoredo to automatically cut commercials when added to postprocessing.bat. I've been using this since reboot first posted this. It has worked for me to cut commercials in HD files recorded in DVR-MS mode.

http://forums.nextpvr.com/showthread.php...omatically

I have never changed anything with this script since it has been working.

I will have to check out the videoredo downconvert feature.

[Braklet]

I guess it doesn't matter if it's pillar boxed. It would have been better to get a sample that was, to test.

I can make one available to you. We recorded last night's Survivor series premiere, which happens to be SD carried over an HD channel. In the US, CBS uses 1080i (1920x1080, 29.97fps).

However, the sample is not raw, since I had to edit out a minute of video using VideoReDo. I left it in DVR-MS format, though.

I have a feeling that every HD channel, possibly every SD show, will require different values for Center Cut. I experimented with a brand spanking new ffmpeg.exe build last night, and found that cropping 200 pixels off of either wing of Survivor preserved final framing much better than 160. I plan to test the Simpsons on Sunday (Fox: 720p 1280x720, 59.97fps).

In any case, when you finalize your solution it would be great if the crop values were accessible through a config file.

BTW, my new ffmpeg.exe does a bang-up job with DVR-MS input. Remember that it already went through a VRD cycle though and that may have taken care of potential sync problems.

Let me know if you want that minute of Survivor SD-over-HD. It is about 110MB.

[Braklet]

(Remember you can have 720x480 4x3 TV and 720x480 16:9 TV. I found out the hard way

Yeah, anamorphic DVDs are 720x480 (p) but still fill the 16:9 frame nicely.

I played around with the "-aspect" flag some and if you don't specify 4:3 ffmpeg gives you a squashed out widescreen.

[Braklet]

VideoReDo now offers DVD authoring in a beta version (if you are a registered user).

Maybe I should pay better attention to the VRD forae! I could definitely use this feature; how does one become a beta tester?

I shelled out $$$ for DVDLab-Studio since none of the other cheaper authoring packages gave me anywhere near the versatility.

But I'm also a big fan of VRD and would like to play around with its authoring function.

[zehd]

I can make one available to you. We recorded last night's Survivor series premiere, which happens to be SD carried over an HD channel. In the US, CBS uses 1080i (1920x1080, 29.97fps).

However, the sample is not raw, since I had to edit out a minute of video using VideoReDo. I left it in DVR-MS format, though.

I have a feeling that every HD channel, possibly every SD show, will require different values for Center Cut. I experimented with a brand spanking new ffmpeg.exe build last night, and found that cropping 200 pixels off of either wing of Survivor preserved final framing much better than 160. I plan to test the Simpsons on Sunday (Fox: 720p 1280x720, 59.97fps).

In any case, when you finalize your solution it would be great if the crop values were accessible through a config file.

BTW, my new ffmpeg.exe does a bang-up job with DVR-MS input. Remember that it already went through a VRD cycle though and that may have taken care of potential sync problems.

Let me know if you want that minute of Survivor SD-over-HD. It is about 110MB.

Yes, I would like that file.

I'm actually working with centercut in ZProcess, as I realized just what you pointed out, that input files can vary in dimensions. ZProcess already works with the input dimensions of files and does calculations to automatically maintain aspect ratio. I'm adding a centercut feature that will do the same, regardless of input dimensions.

I could send you the commandlines that I have already, but you would have to tweak the command line case by case, or be rather sneaky with the batch file.

I'll have round two of writing tonight... The file would be great...