2. Cinepak movie production

The process of bringing original audio, video, and graphic material into the SEGASATURN format varies depending on the original source material and final format. Where you start the process, the number of steps, and the tools you need all depend on what equipment you have and what you want to accomplish. This chapter provides information to help you decide which method is best for you.

2.1 Process overview

The general process steps are shown below. The actual steps will vary depending on what you are working on.

Figure 2.1 Cinepak movie production procedure

	・Determine frame size, frame rate, and sound ・Transfer rate from CD
	・Import images and sounds from VCRs, laser discs, cameras, QuickTime animations, PICT files, CG, animation files, etc. and convert them into QuickTime movies.
	・Use QuickTime tools ・Edit the sequence and length ・Apply effects to the movie if necessary ・Additionally edit the soundtrack ・If you want to change the sound rate, cut and save the sound after editing
	・Set Quality, Key Frame and other necessary items ・Compress with Cinepak
	- Add sound if necessary
	・Use MovieToSaturn_J to compress Cinepak and QuickTime movies Convert to movie for SEGA Saturn
	・If available, transfer to a virtual CD machine via LAN ・Convert files between Mac and PC as necessary
	・Add Cinepak players using the Cinepak library ・Add sample programs as necessary
	・Create a CD image file with virtual CD

2.2 Movie production plan

To create a Cinepak movie and use it in a game application, you need to plan in advance what kind of movie you want to create.
SEGASATURN's CD-ROM transfers data at 300KB/S in double speed mode. Therefore, the movie you create must be lower than that transfer rate.

Figure 2.2 is a graph of Cinepak compression of a natural image movie with a frame size of 320 x 224 pixels and 256 x 160 pixels and no sound. As you can see from these figures, the compression ratio worsens as the image quality increases, and the data transfer rate increases. In an actual movie, sound is added to this, so the following formula must be satisfied.

Sampling frequency x A x B + image transfer rate< 300KB/S……(Formula 2.1)

A: For 8bitPCM   A=1
   For 16bitPCM  A=2
B: For mono      B=1
   For stereo    B=2

Please refer to the diagram for the image transfer rate. However, the actual compression rate will vary depending on the content of the movie, so refer to these figures to roughly determine the frame size, frame rate, and sound, then try compressing the movie you want to use and adjust the transfer rate using the image quality settings. Better to adjust.

Figure 2.2 Transfer rate for image quality settings (320×224)

Figure 2.3 Transfer rate for image quality settings (256×160)

●Frame rate depending on display color

Movies compressed with Cinepak are created with 16M colors (24-bit color). When decoding this movie, it is converted to 16 bits/pixel (MSB is a transparent bit, RGB is 5 bits each) when playing in 32K colors, and expanded to 32 bits/pixel (when playing in 16M colors). The upper 1 byte is for the transparent bit (RGB is 8 bits each). In other words, there is no problem as long as the movie compression rate is the same (the movie data is the same) and the image transfer rate satisfies the above (Equation 2.1) no matter which way you play it.
However, when playing with 16M colors, there is twice as much data as when playing with 32K colors, and the transfer to VRAM also requires some consideration, so the frame rate must be lower than when playing with 32K colors.
The frame rate depending on the display color will vary depending on the content of the movie, but please refer to the following values as a rough guide.

1. 32K colors, 320×224 size 24~30fps
   To ensure image quality, 24fps or less is appropriate.

2. 16M colors, 320×224 size 15~18fps

〈 reference〉

About 16M color reproduction
When playing in 16M colors using the scroll surface of VDP2, first expand one frame of data to work RAM and then transfer it to VRAM using SCU's DMA. As shown in Figure 2.4, data is transferred to VRAM in the upper half while the TV scanning line is in the lower half. Then, transfer the data in the bottom half while the scan line is in the top half area. In other words, the VRAM is rewritten while being chased by the TV's scanning line. These processes must be completed within 1Vsync period, and the SUC's DMA is used to transfer them at high speed so as not to catch up with the scanning line. Figure 2.5 shows the timing of data transfer to VRAM.

Figure 2.4 Image of data transfer to VRAM

Figure 2.5 Image of data transfer to VRAM

2.3 Capturing video and sound

To create a movie for Cinepak, you need a QuickTime movie file as the source material. To transfer source material to QuickTime, there are countless possible combinations of procedures and device configurations, but please refer to the following method as an example.

●Import from video source

When importing video into a QuickTime file, input the source (VCR, camera, laser disc, etc.) into the QuickTime application via the Macintosh's video capture board.
For the best quality, capture footage as uncompressed as possible. To import uncompressed, use the VCR's control board to import one frame at a time. To import data in real time without compression, you can use a high-speed hard disk (DiskArray type), or you can import it to RAM and then write it to the hard disk. For operating instructions, please refer to the manual for the device you are using.

●Import from Macintosh graphic source

If you have a still image in Macintosh file format (PICT format),
Create a QuickTime file using the MovieConverter utility.

●Importing from digital materials other than Macintosh

Use the DeBabelizer utility program to convert non-Macintosh (graphics data from workstations or other PC machines) files to QuickTime format.

●Sound capture

Record in AIFF format via the Macintosh soundboard. For digital sounds such as DAT, please use a commercially available waveform editor to record the sound to the hard disk and then resample it to the desired sampling frequency.

2.4 Editing QuickTime movies

At this point, edit the story, sequences, soundtrack, and add effects and filters if necessary. The editing tool for QuickTime movies is Adobe Premiere from Adobe System. Also, you can use the filters in the Plug-ins of Adobe PhotoShop, also from Adobe System, in Premiere, so please try them out. For details, please refer to the manual of each software.

●About movie division

A Cinepak movie in SEGASATURN format consists of a movie header and movie data (video + sound, called sample data), as shown in Figure 2.6. This header contains information about the entire movie and sample information. Sample information is information for each frame of video and information for each interleaved sound, and 16 bytes are required for one sample. The movie header size can be calculated using the following formula.

H=(L×F+4L−1)×16+80……(Formula 2.2)
H: Header size [bytes]
L: Movie length [seconds]
F: Frame rate [fps]

For example, if you create a 10 minute movie at 30fps with sound, the header size will be approximately 320KB.
The header must always exist in memory during movie playback, so if you create a long movie, the movie header will become large and take up space in SEGASATURN's work RAM area. Also, if the header is large, it will take time to read it from the CD-ROM, which will slow down the start of movie playback. To avoid these problems, divide the movie and play it continuously. The Cinepak library allows you to seamlessly play split movies continuously by registering the next movie to play.

Figure 2.6 Cinepak for SEGASATURN movie file format

	General information about the movie and Sample tapes and details of each sample
	Offset for each sample data, Sample data size, display time information
	Sample data 0 always contains sound data. Contains 1/2 second

●When changing the sampling frequency of the sound

Usually, the sounds handled by QuickTime editing tools are 44.1KHz, 22.254KHz, and 11.127KHz. On the other hand, SEGASATURN can play sampling frequencies below 44.1KHz. If you want to use a sound other than 44.1KHz, 22.254KHz, or 11.127KHz, use a QuickTime editing tool like Adobe Premiere to cut the original soundtrack, save it to an AIFF file, and use a sound utility to cut it. Downsample that AIFF file. Next, add downsampled sounds to your movie after compressing it with Cinepak.

2.5 Cinepak Compression

Use a compression utility such as Apple's MovieConverter to compress your movie with Cinepak, available in the Compressor pop-up menu. Select Color for the color depth (some compression utilities have over 1000 million colors). Please note that Grayscale cannot be used. After that, set the quality, frame rate, etc. to the required values and compress with Cinepak.
It doesn't matter what the audio block is set to.

2.6 Adding sounds

If you want to add sound after creating a Cinepak movie with only images, use MoviePlayer. Open the AIFF format sound file with MoviePlayer (it will be a movie without video). Similarly, open a Cinepak movie with only video and paste the movie with only sound. Make sure to hold down the Option key when pasting.

operation

1. Open the video-only Cinepak movie and the additional sound file in MoviePlayer
2. Copy a movie with only sound after Select All
   
3. After selecting a Cinepak movie with only images, hold down the Option key and Paste.
4. After confirming playback, save

2.7 Conversion to SEGASATURN format

Use MovieToSEGASATURN_J to convert edited Cinepak compressed files to SEGASATURN format movie files.

operation

1. Copy MovieToSaturn_J to an appropriate folder on Macintosh.
2. Start MovieToSaturn_J, select the file you want to convert, and click the "Open" button (Figure 2.7).
3. A save dialog will open, so enter the file name to save it (Figure 2.8). By default, ".CPK" is added to the end of the source file name.
4. Click the "Save" button to start the conversion.
5. It will close automatically when the conversion is finished.

Figure 2.7 MovieToSaturn_J movie selection dialog

Figure 2.8 MovieToSaturn_J movie save dialog

You can also convert by drag and drop. Drop the Cinepak file you want to convert onto the MovieToSaturn_J icon to start conversion. In this case, if the extension is ".MOV", rewrite the file name to ".CPK", otherwise add ".CPK" to the original file name.

2.8 Transfer Cinepak movies to DOS

Convert movies to DOS files using Apple File Exchange. Also, if LAN service is available, transfer it to a PC/AT compatible machine for virtual CD via the network.

2.9 Adding code for Cinepak driver

Create an application using the Cinepak library. For information on the Cinepak library, see "Chapter 4 Cinepak Library." Also, if necessary, please refer to the sample program source code provided with the Cinepak library.

2.10 Creating files for CD-ROM

Create a CD image with Virtual CD and check the playback content.