Use Case: DVD
Example of Video Source with 4:3 Aspect Ratio, Being Transcribed to 16:9 and Creating a DVD to be Displayed on a Digital TV. Illustrated steps to take source input with 4:3 aspect ratio and convert to 16:9, with the bottom of the image being cropped in order to preserve top of video so nobody's head gets cut off are provided here.
- In order to write to a DVD writer hardware device, you must be root!!
- Start CINELERRA-GG to bring up the 4 usual screens with main track canvas in the lower left corner.
- Load media via the pulldown File
→ Load files...by choosing the directory path with the desired file.
- Bring up the Create DVD window using File
→ DVD Render.
- Choose Format: PAL or NTSC with 16x9 aspect ratio for today's digital TV as in below screenshot. figure 14.9.
Choose NTSC or PAL for DVD creation
- Modify the Work path: parameter to a disk that has sufficient disk space and you will see the
amount of disk space in green letters (/tmp is default, but is often deleted so may be a bad choice).
- Note that in the following screenshot, Scale of Cropped has been chosen (figure 14.10).
Set Scale Ratio to Cropped
- Click the green checkmark on the bottom left side of the window to close it and proceed.
- Now the Batch Render window will appear along with the Scale Ratio brown-colored line below the video in the main track canvas as seen in the screenshot below. Note that in this screenshot the top right most corner of the shot displays the bottom portion of the Compositor window.
- Next, right mouse click the gold-colored magnifying glass, which is on the right hand side of the brown-colored line. This will bring up the Scale Ratio window that you can see below. Note in the Compositor window, the blue legs are only showing up to the knees.
With the Scale Ratio plugin you can manipulate your video so that it will look the way you want it on a different output Display device. In this case we are going to create a DVD for playing on a Digital TV screen.
In figure 10.59, the left side shows the Input Ratio, Width, and Height of input. The top right half shows desired output values. In this particular case, the input was a YouTube video which was not quite 4 : 3 aspect ratio.
Scale Ratio plugin
Left and right sides of the bottom portion show the Source and the Destination X, Y, W, H values. As you change the values on the left side, you can see how this will affect the output as you observe the results in the compositor window. For example, as you change the values for SrcY in a cropped Scale scenario, you see up/down movement.
Keep in mind that the monitor you are using is NOT the intended output display device – your digital TV is, which most likely will have different looking aspect/pixels, etc.
- In order to crop the bottom of the video in order to preserve all of the image on the top, modify the Src Y value on the bottom of the left hand side in the Scale Ratio plugin. Src Y which was 21 has now been changed to -18. You will see in the Compositor window how the bottom dark colored border is now gone so that none of the top portion which contains the Bunny's head will be chopped off. Compare figure 14.12 to figure 14.10 and note the Bunny's head.
Better scale on compositor
- Click the Apply box in the Scale Ratio window.
- Click the Save to EDL Path in the Batch Render window for creating a DVD. If you do NOT do this, you will get a Warning box as seen in figure 14.13, to remind you to Save because you have changed the EDL by modifying the scaling parameters in the Scale Ratio window.
Error in Batch Render
- Next, make sure you have the Timeline set in the Main window at the beginning of where you want to start rendering. Also, make sure the first line in the Batches to render section is highlighted as you can see above by the blue highlighting. Click on the Start box in the Batch Render window and you will see the video playing in the Compositor window.
- CINELERRA-GG program will be stopped when done rendering; you will be at the terminal prompt where you will see it has printed out some informational messages (or errors if problems), the last 2 are:
To burn dvd, load blank media and run:
growisofs -dvd-compat -Z /dev/dvd -dvd-video /mnt0/dvd_20161027-131723/iso
- Load a blank or rewritable DVD into your DVD writer device, which will be similar to /dev/dvd as in the growisofs line above – something like /dev/sr0 on your computer.
- Keyin the growisofs line, substituting your actual writer device name. Again, you must be root.
- When back at the terminal prompt, and if there are no errors, keyin eject /dev/dvd substituting.
- Play it on your DVD player connected up to your Digital TV screen.
The CINELERRA-GG Community, 2021