How to add black bars to Crop video without changing dimensions

[DavidCasillas]

I have a .dv video of my band playing a gig. I want to crop it a bit so the image just focos on the stage.

I have one question. If a crop it, the final size will not be 4/3. Wil the video be streched when I later send it to iMovieHD and then iDVD to burn a DVD?

If this is going to happen. How can I instead of crop, just add black bars to remove the unwanted borders but keep the 4/3 image ratio?

[DavidCasillas]

Suddenly I have see the light.

I have used VisualHub.

In Advanced window I have set the desired croping. Then I have set the size as:

New Height = 720-uppercrop-bottomcrop
New Width = 576-leftcrop-rightcrop

So the movie will not be streched

Then I export as dv file. The output will be a 4/3 (720*576) file with black borders.



It is posible also to remove the upper or side black borders (the ones with less croping).

In my case I have remove few in the sides so I did the following divison:

576 / New-Width

and use it to calculate the FinalHeight without changing any image ratio.

FinalWidth: 576
FinalHeight: NewHeight * (576 / New-Width)

I'm sorry, this easy task looks so complicates in my explanatios.

Maybe I'n reinventing the wheel and there is a reaaly simple way of doing this, please tell me.

[Herve]

ouch! too complex and unsafe (use the QuickTime decoder to deinterlace first or your resulting file/interlacing will be damaged)

command line:
ffmpeg -f dv -i input.dv -croptop (yourValue1 as integer) -cropbottom (yourValue2 as integer) -cropleft (yourValue3 as integer) -cropright (yourValue4 as integer) -padtop ((yourValue1+ yourValue2)/2, had to be an even value as integer) -padbottom (same value than padtop) -padleft ((yourValue3+ yourValue4)/2, had to be an even value as integer) -padright (same value than padleft) -ar 48000 -y ~/Desktop/output.dv

this seems complex, it's not

eg (complex crop, with centerd result):
ffmpeg -f dv -i input.dv -croptop 10 -cropbottom 50 -cropleft 30 -cropright 50 -padtop 30 -padbottom 30 -padleft 30 -padright 30 -ar 48000 -y ~/Desktop/output.dv

eg (simple "replace areas with black"):
ffmpeg -f dv -i input.dv -croptop 10 -cropbottom 10 -cropleft 10 -cropright 10 -padtop 10 -padbottom 10 -padleft 10 -padright 10 -ar 48000 -y ~/Desktop/output.dv


PS: or contact me by mail

bye

Edit: command line correction

[DavidCasillas]

Thanks one more time Herve.

But as always when I try to play around with video, every answer open more questions.

1.- What you mean it is not a safe workflow? What are the dangers?

2.- If the final output will be DVD, is it a good idea to deinterlace it first?

3.- Do you mean that if I use the VisualHub workflow I should check the deinterlace box and choose force Quicktime encoder?

4.- Or do I always deinterlace, even using ffmpeg workflow?

5.- I have never used ffmpeg, I have tryed adding some flags to the VisualHub Advanced Window but it seems not working. So I now learning how to install ffmpeg (not an easy task). I will post when I get some result.

[Herve]

1.- What you mean it is not a safe workflow? What are the dangers?

interlacing is like an embroidery, do not play too much with it or the contents of your video will be mixed (fields badly displayed)

2.- If the final output will be DVD, is it a good idea to deinterlace it first?

No, a very bad idea (but it's the safer way to manipulate interlaced stream )

3.- Do you mean that if I use the VisualHub workflow I should check the deinterlace box and choose force Quicktime encoder?

I don't know exactly (I hadn't use it for a long time)
but QuickTime decoding inside VisualHub always deinterlace (it's a bug of the decoding tool)

4.- Or do I always deinterlace, even using ffmpeg workflow?

to deinterlace an DV stream (QuickTime or ffmpeg) = remove hyalf of the informations of your input file
Some deinterlacers are better (but not these ones)

Directly take the one installed on your disk with my app (home folder /Library/Application Support/MovieConverter )

bye

[DavidCasillas]

I have tried and get an error: Unknown input or output format: pal-dv

I have search but could not get an answer of what is going wrong. Here is the terminal screen.

macbook-de-david-casillas-rivero:~ davidcasillasrivero$ ~/Desktop/ffmpeg -f dv -i ~/Desktop/input.dv -croptop 10 -cropbottom 10 -cropleft 10 -cropright 10 -padtop 10 -padbottom 10 -padleft 10 -padright 10 -f pal-dv -y ~/Desktop/output.dv
FFmpeg version SVN-r16722, Copyright (c) 2000-2009 Fabrice Bellard, et al.
configuration: --enable-postproc --enable-gpl --enable-pthreads --enable-static --disable-shared --enable-gray --enable-libx264 --enable-libmp3lame --enable-libgsm --enable-libfaac --enable-libfaad --enable-swscale --enable-avfilter --disable-decoder=aac
libavutil 49.14. 0 / 49.14. 0
libavcodec 52.11. 0 / 52.11. 0
libavformat 52.25. 0 / 52.25. 0
libavdevice 52. 1. 0 / 52. 1. 0
libavfilter 0. 2. 0 / 0. 2. 0
libswscale 0. 6. 1 / 0. 6. 1
libpostproc 51. 2. 0 / 51. 2. 0
built on Jan 25 2009 19:10:33, gcc: 4.0.1 (Apple Computer, Inc. build 5370)
Input #0, dv, from '/Users/davidcasillasrivero/Desktop/input.dv':
Duration: 00:00:20.16, start: 0.000000, bitrate: 28800 kb/s
Stream #0.0: Video: dvvideo, yuv420p, 720x576, 28800 kb/s, PAR 59:54 DAR 295:216, 25.00 fps(r)
Stream #0.1: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
Unknown input or output format: pal-dv

[Herve]

'cause I made a mistake (I said "-f" instead of "-target")
sorry
(I modified the command line in the previous post, and added one parameter more)

bye