You can design, author, and build media projects in Adobe® Encore® for high-definition Blu-ray Disc and standard-definition DVD. Encore gives you options to burn directly to a disc or other types of output for disc replication. As an added bonus, you can export Blu-ray and DVD projects to Flash format for interactive viewing on the web.
Planning the content
The first task of authoring the project is planning. This planning can be as minimal as deciding to use a template to organize your family’s vacation photos and video, or as robust as using project-management software to coordinate a production team creating an interactive kiosk.
Whatever the scope of planning, you should understand what the project will contain and how you want to present it. By the end of the planning stage, you should have a good understanding of the following parameters.
A well-produced project employs a hierarchy of navigation that gives the viewer clear and easy access to the content. Think through your project. After you decide which clips you want to include, you need to determine how the viewer will access those clips. Whether you use a spreadsheet or a pencil sketch, it is worth the time to draft your navigation scheme before you start.
Is the project intended for television viewing? Will it play unattended in a kiosk? Is it for use in an educational setting on computers? The playback environment affects your approach to navigation and the design of the menus as well as the content. If the project will be used only on a computer (on the desktop or in a web browser), you can include ROM content that a television DVD or Blu‑ray player cannot access. For instance, you can include PDFs of exercises in an educational DVD to be used on the computer. If you’re planning to export your project to Flash format, you can embed web links that connect your project to other areas in your website.
To make certain decisions—for instance, about disc size and video data rate—you need to know how much content you must fit on the disc and what type it is (such as standard-definition or high-definition video). Small projects that include mostly audio might fit on a single-layer DVD, whereas projects containing feature-length movies and many supplemental materials might require a dual-layer or dual-sided DVD or a Blu‑ray disc.
The Flowchart feature provides a visual interface that helps you to plan and manage the creation of the project. Use the Flowchart from the initial stages of the project, when you determine navigation and begin organizing assets.
If you’re new to authoring these types of projects, plan your navigation scheme on paper and start using the Flowchart after you are familiar with the different element types and their properties.
The Flowchart displays the content of the project graphically, in a tree structure, detailing the navigation between the different elements. This visual representation can help you to see areas where the navigation is cluttered and you want to refine. Beyond providing a visual representation of the project, the Flowchart also lets you perform many authoring tasks, such as setting project navigation.
If your project contains multiple hierarchical objects, use the zoom controls on the flowchart panel to view the relevant parts of the flowchart. In addition, the tool tips show asset names when you hover the mouse over them.
For a video tutorial about using the Flowchart to plan your projects, see www.adobe.com/go/vid0240.
Balancing file size and quality
Authoring a DVD or Blu‑ray project involves striking a balance between two competing properties: file size and video quality. As quality increases, so does file size. You want to achieve the highest possible quality for your content while keeping the file sizes small enough so that all of the content will fit on the disc. This balance is achieved by manipulating the video content’s data rate—either automatically (by letting Encore set the data rate) or directly (by setting the transcoding settings or using a third-party application).
You determine the optimal data rate through the process of bit budgeting. To understand bit budgeting, you first need to understand the variables involved: disc size, types and amounts of assets (audio, video, and motion menus), and data rates and transcoding. Once familiar with the variables involved, you’ll be able to produce a bit budget to guide you in producing high-quality projects that fit within the allotted disc space.
Before you can prepare a bit budget, you must determine the size of disc on which to distribute your project. Encore can create projects for 25‑GB Blu‑ray discs and for a variety of DVD disc sizes. The size you choose is based on the amount of video and the replication method.
Typically, a Blu‑ray disc can hold 135 minutes of high-definition video using MPEG‑2 plus 2 hours of standard-definition bonus material, or it can hold a total of 10 hours of standard-definition content. Encore also supports H.264 encoding for Blu‑ray projects, which provides better quality at lower bit rates than MPEG‑2 and therefore more video time. Desktop DVD burners use a recordable DVD‑5 disc (DVD+/‑R), which has a 4.7‑GB capacity and can hold approximately 2 hours of high-quality, standard-definition video.
Encore also supports DLT (digital linear tape), which requires a DLT drive connected to your computer, as well as dual-layer DVDs and dual-sided DVDs. Check your DVD recorder’s documentation to see if it can create dual-sided or dual-layer discs. If your disc recorder cannot produce these discs, Encore can still create the project files for them, but you’ll need to replicate the disc at a replication facility.
When preparing a project for dual-layer or dual-sided DVDs, keep the following information in mind:
Encore supports DVD‑R DL and DVD+R DL discs; check your recorder’s documentation to see what type of DVDs (+R or ‑R) it requires. To replicate dual-layer DVDs at a replication facility, you first must write your project to two separate DLTs, one tape for each layer of the disc, using the DVD Master output option. (See Build a DVD or Blu‑ray disc and Specify a layer break for dual-layer DVDs.)
Be aware that +R discs may be incompatible with some DVD players. Before duplicating a large quantity of discs, it’s worthwhile to create a sample disc and test it on several different DVD players. Replication facilities, whose paramount purpose is duplicating discs, create discs with the widest possible compatibility.
Dual-sided, dual-layer disc
In this case, you need to build two projects, each producing two tapes. The first two tapes represent the two layers of the first project (Side 1). The other two tapes represent the two layers of the second project (Side 2).
By setting the disc size for your DVD project at the beginning of the authoring process, Encore can calculate how much space is used for each asset you add to the project and how much space remains free.
The Build panel displays the available space and the used space for the specified disc size during the authoring process. The display conveys size information only and has no bearing on quality. Encore calculates the free space using the transcoding data rate (whether it was set automatically or manually). It then combines this estimated bit rate with the actual bit rate of any transcoded clips and, based on the disc size, calculates the space remaining on your disc.
When transcoding assets, Encore attempts to maintain the highest quality (highest data rate) for the amount of video in the project. If you continue to add video to a project, the program lowers the video data rate to squeeze in the additional content. Encore will warn you if quality dips below a certain level once you build the project or run Check Project.
Of all the content types, the video portion occupies the most disc space. Depending on the data rate, 1 minute of standard-definition video for DVD projects can occupy up to 73.5 MB, at a rate of 9.8 megabits per second (Mbps). One minute of high-definition video for a Blu‑ray project can occupy from 270 to 405 MB (using rates of 36 Mbps and 54 Mbps). One minute of compressed audio, on the other hand, occupies only 11.5 MB. Still menus are negligible in terms of size. (See Average asset size.)
The amount of video in a project directly affects the optimal data rate. You need an accurate tally of the amount of video in a project to develop a bit budget and to choose a disc size. If the project contains 1 hour of video, for example, it can be transcoded at twice the data rate as a project with 2 hours of video content. Although the video content in each project occupies the same amount of disc space, the quality of the hour-long video will be superior (though not necessarily by a factor of 2).
Data rates, usually expressed in Mbps (megabits per second, or 1,000,000 bits per second), specify the amount of data contained in an asset stream and directly affect the quality of video. The data rate is used during transcoding to compress the asset. For video assets, the Encore transcode presets use data rates ranging from 15 to 40 Mbps for Blu‑ray projects and from 4 to 9 Mbps for DVD projects. You can edit the presets’ data rates, but you cannot exceed 40 Mbps for Blu‑ray projects or 9.0 Mbps for DVD projects, nor can you go below the Encore minimum data rate of 2.0 Mbps. Typical data rates for video range between 4 and 6 Mbps. If bit budgeting targets a data rate less than 6 Mbps, consider using variable bit rate (VBR) encoding. For more information about VBR, see Calculate a bit budget.
Although data rates are a general indicator of quality, there are no hard-and-fast rules to equate data rate to quality. That is, a data rate of 4 Mbps may or may not produce a high-quality asset; quality depends on the image data and type of compression used as well as data rate. For example, video of a seated person shot against a solid background can probably be compressed to a lower data rate than a fast-paced car chase with constantly changing visuals, with no noticeable differences in quality.
Bit budgeting, or estimating the amount of space your project will occupy, is an important part of planning. Bit budgeting helps you strike a balance between the quantity and quality of content and determine the optimal video data rate. If your project includes minimal amounts of content, you can encode that content at a higher data rate (which translates to higher quality) to take advantage of all available space. Conversely, if your project contains a large amount of content, you need to use a lower data rate (which translates to lower quality) to squeeze it all onto the disc.
Encore automatically tracks bit budgeting during the authoring process. For small projects with limited content, simply checking the amount of available space on the Build panel during the authoring process is usually sufficient to track your space usage. For large, complex projects, though, bit budgeting becomes much more important to the authoring process, providing a check against the actual data rates achieved.
Generally, for projects with less than 2 hours of video, you can skip bit budgeting and let Encore set the data rate automatically.
Bit budgeting provides a target video data rate for the project. You can either use a pencil and paper to quickly develop one, or you can create a spreadsheet to do the calculations for you.
When bit budgeting for projects to be distributed on 4.7‑GB DVDs that contain a single stream of compressed audio, you can use the simplified formula of 560 / x = bit rate in Mbps, where “x” represents minutes of video.
Calculate the disc space available for video. You achieve this by calculating the space required for audio, slide shows, subtitles, and motion menus (other types of content are negligible in terms of bit budgeting), and subtracting that amount from the total disc space. For more information, see Average asset size.
If you include ROM content, make sure to include it in the space calculation. (See Add ROM content to the disc.)
Determine the maximum video bit rate by subtracting the combined audio and subtitle rate from the data rate limit. (For example, if your combined audio and subtitle rate is 3.0 Mbps, subtracting that from the 9.8 Mbps DVD data rate limit gives you a video rate of 6.8 Mbps.) Your goal is to determine the highest possible target video data rate within the disc data rate limit. If your target data rate is below 6 Mbps, consider using variable bit rate (VBR) encoding. When you use VBR encoding, you specify the maximum video data rate. (The average data rate is the target, but the maximum rate provides some flexibility when encoding.)
Keep your calculations simple by working with megabits (Mbits) and not megabytes (MB) when bit budgeting. Mbps denotes megabits per second. Also, hard-disk capacity is typically calculated as a power of 2 (1 KB = 2^10 bytes = 1024 bytes), while optical disc (DVD) capacity is labeled as a power of 10 (1 KB = 10^3 bytes = 1,000 bytes). Use the power‑of-10 scheme for bit budgeting. The following conversion factors will aid in the calculations: 1 GB = 10^9 bytes = 1,000,000,000 bytes = 8,000,000,000 bits; 1,000,000 bits = 1 Mbit.
If compressed using the Dolby® Digital Stereo standard, audio is generally 192,000 bits per second (0.192 Mbps). Use 0.192 Mbps or reference the settings for the audio encoder you plan to use.
Insignificant in terms of bit budgeting, unless you include subtitles. If you do include subtitles, use 0.010 Mbps per subpicture stream for calculations.
Typically have a data rate of 8 Mbps for the transcoded standard-definition video or 40 Mbps for high definition; add this to the audio data rate. (If the video is already DVD‑ or Blu‑ray-compliant, then it won’t be transcoded, and you should use the data rate of the video file.)
Typically insignificant in terms of bit budgeting and can usually be left out of the calculation. Still menus average 230 KB in size.
The asset size for a slide show depends on whether you include transitions or the Random Pan & Zoom effect:
If the slide show contains no transitions or effects, the slides are written to the disc as MPEG stills, which require minimal space. Stills average 230 KB in size, which is typically negligible for bit budgeting. If you have a large number of images, however, you should include them in your calculation.
If the slide show includes transitions, then Encore writes both stills and transcoded MPEG video files for the transitions. For example, if a given image appears for 10 seconds, with a 2‑second transition at the beginning and the end, then the still is written to the disc (displayed for 6 seconds) as well as two 2‑second MPEG video files that contain the transition frames.
If the slide show includes pan and zoom, then Encore transcodes the stills into an MPEG video file. Slide shows with pan and zoom, in essence, become video content and require the same space allotment as video files. For example, a 5‑minute slide show that uses pan and zoom throughout counts as 5 minutes of video content for bit-budgeting purposes.
Bit budgeting for a simple DVD project containing 2 hours and 13 minutes of standard-definition video, without any audio, to be distributed on a 4.7‑GB disc proceeds as follows:
Calculate the disc space available for video. Combine the size of the audio, subtitles, motion menus, 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. Since this example has no audio, subtitles, or motion menus, you subtract only the 4% for overhead (1,504,000,000 bits) to get a value of 36,096,000,000 bits.
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.
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. This data rate (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.
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:
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.
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.
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 25‑GB disc:
127‑minute audio stream with a data rate of 0.192 Mbps = 127 minutes x 60 seconds x 0.192 = 1,463.04 Mbits; divided by 8 bits = 182.88 MB, rounded off to 183 MB.
30‑second menu audio stream = 30 seconds x 0.192 Mbps = 5.76 Mbits; divided by 8 bits = 0.72 MB, rounded off to 1 MB.
8‑minute slide show audio stream = 8 minutes x 60 seconds x 0.192 Mbps = 92.16 Mbits; divided by 8 bits = 11.52 MB, rounded off to 12 MB.
30‑second motion menu at 40 Mbps = 1,200 Mbits; divided by 8 bits = 150 MB.
8‑minute slide show video (all pan and zoom) at 20 Mbps = 8 minutes x 60 seconds x 20 Mbps = 9,600 Mbits; divided by 8 bits = 1,200 MB or 1.2 GB.
Total disc space required = 183 MB + 1 MB + 12 MB + 150 MB + 1,200 MB = 1,546 MB or 1.546 GB.
Calculate the data rate of the video by dividing the disc space available for video (in step 3) by the amount of video (in seconds) the project contains.
183,632 Mbits available (22.954 GB x 1,000 MB/GB x 8 bits per byte) divided by 7,620 seconds of video (127 minutes x 60 seconds per minute) = 24.10 Mbps.
127 minutes of video at 24.10 Mbps = 22.96 GB.
(127 x 24.10 x 60 seconds = 183,642 Mbits, divided by 8 = 22,955.25 MB, divided by 1,000 = 22.96 GB).
Determine the maximum video data rate for this project by subtracting the combined audio data rates from the disc’s maximum video data rate of 40 Mbps.