Adobe 22030000 User Guide - Page 35

ENCORE CS3 31 User Guide 3 Calculate the data rate of the video. Divide the disc space available for video that you determined in step 2 by the amount of video (in seconds) the project contains. 36,096,000,000 bits / (133 minutes x 60 seconds per minute) = 4,523,308.27 bps. Divide the bps amount by 1 million bits per Mbit to convert the video data rate to Mbps. 4,523,308.27 / 1,000,000 = 4.5 Mbps. 4 Determine the maximum video data rate. Subtract the combined audio, subtitles, and motion menu data rates, zero in this instance, from the maximum DVD video data rate of 9.8 Mbps. 9.8 Mbps - 0 = 9.8 Mbps. Because this is very close to the maximum rate for DVD, you can lower it to 9.0 Mbps to be safe. The video will fit on the disc using a data rate of 4.5 Mbps. 4.5 Mbps is low enough (below 6 Mbps) that you should use VBR encoding. The maximum video data rate for VBR encoding is 9.0 Mbps. Sample budget #2 Proceed as follows for bit budgeting of a 120-minute standard-definition video with three audio tracks, two subtitle tracks, two motion menus, and a 1-minute movie preview to be burned to an 8.54-GB DVD: 1 Calculate the total available disc space in bits. An 8.54-GB disc contains 8,540,000,000 bytes; each byte contains 8 bits. 8,540,000,000 x 8 = 68,320,000,000 bits = 68,320 Mbits. 2 Calculate the disc space available for video. Combine the size of the audio, subtitles, motion menus, movie preview, and 4% of the disc capacity (for overhead, just to be safe) and then subtract that sum from the total available space you calculated in step 1. • Three 120-minute audio streams, two with a data rate of 0.192 Mbps and one with a rate of 0.448 Mbps: (2 x (120 minutes x 60 seconds per minute x 0.192 Mbps) + (120 minutes x 60 seconds per minute x 0.448 Mbps) = 5,990.4 Mbits. • Two subtitles with a data rate of 0.010 Mbps: 2 x (120 minutes x 60 seconds per minute) x 0.010 Mbps = 144 Mbits. • Two 24-second motion menus with an estimated data rate of 8 Mbps: 2 x (24 seconds x 8 Mbps) = 384 Mbits. • One-minute movie preview with a data rate of 4.5 Mbps: 60 seconds x 4.5 Mbps = 270 Mbits. • 4% overhead: 0.04 x 68,320,000,000 bits = 2,732,800,000 bits = 2,732.8 Mbits. • Total audio, subtitles, motion menus, preview, and overhead sizes: 5,990.4 Mbits + 144 Mbits + 384 Mbits + 270 Mbits + 2,732.8 Mbits = 9,521.2 Mbits. • Disc space available for video: 68,320 Mbits - 9,521 Mbits = 58,799 Mbits. 3 Calculate the data rate of the video. Divide the disc space available for video that you determined in step 2 by the amount of video (in seconds) the project contains: 58,799 Mbits / (120 minutes x 60 seconds per minute) = 8.16 Mbps. 4 Determine the maximum video data rate. Subtract the combined audio and subtitles data rates from the maximum DVD video data rate of 9.8 Mbps: 9.8 Mbps - (0.192 + 0.192 + 0.448 + 0.010 + 0.010) = 8.95 Mbps. The video will fit on the disc using a data rate of 8.16 Mbps, which is below the maximum video data rate of 8.95. Furthermore, because the target video data rate of 8.16 Mbps is above 6 Mbps, you do not need to use VBR. Sample budget #3 Here is an example of a bit budget for a Blu-ray Disc project that contains 2 hours and 7 minutes of high-definition (HD) video and audio, one 30-second HD motion menu with 30 seconds of audio, and one HD pan-and-zoom slide show containing 50 slides and 8 minutes of audio (total slide show duration is 8 minutes), to be distributed on a 25GB disc: 1 Total available disc space is 24.5 GB (25-GB disc capacity minus a very conservative 2% overhead of 0.5 GB).