These parameters control what happens when you play sound from the timeline.
AUDIO INPLAYBACK DRIVER - The playback driver driver is used when playing sound from the timeline. Set the parameters for audio output. Broadcast 2000 has three modes in which it uses an audio device: Playback, Record, and Duplex.
Each mode supports a subset of the many sound drivers available for Linux. The drivers are described below.
SAMPLES TO READ FROM DISK: Broadcast 2000 uses a pipeline for rendering audio. The first stage is reading large chunks of audio from disk, the samples to read from disk.
SAMPLES TO SEND TO CONSOLE - The second stage is rendering small fragments through the console to the sound driver. A larger value here causes more latency when you change mixing parameters but gives more reliable playback.
PRELOAD SIZE - determines the minimum number of bytes in a SEEK_SET before switching to a sequential read. A typical value is 2000000. For playing movies, the preload buffer allows audio and video to play back without seeking back and forth. This eliminates seeking on slow CD-ROM drives while increasing latency. Set to 0 to eliminate prebuffering.
DISABLE TRACKS WHEN NO EDITS - During parts of the timeline which don't have any footage, Broadcast 2000 can either render silence or not render the track at all. Selecting Disable tracks when no edits causes tracks to be turned off when they have only silence. This speeds up video rendering considerably, allows more scenes to be viewed without alpha channels, but can cause transitions and plugins to turn off when they should be on.
VIEW FOLLOWS PLAYBACK - Causes the timeline window to scroll when the playback cursor moves out of view.
USE SOFTWARE FOR POSITIONING INFORMATION - Many soundcards and sound drivers don't give reliable information on the number of samples the card has played. When playing video you need this information for synchronization. This option causes the sound driver to be ignored and a software timer to be used for synchronization.
AUDIO PLAYBACK IN REALTIME - Back in the days when the AMD K6 was king, this allowed uninterrupted playback on heavy loads. Now you'll never need it.
These parameters control what happens when you record sound.
PERFORMANCERECORD DRIVER - Determines the device used to bring audio into the system.
DUPLEX DRIVER - Device used to play back while a recording is in progress.
SAMPLES TO WRITE TO DISK AT A TIME - Recording audio is performed using a pipeline. Fragments are rapidly read from the sound driver but only committed to disk in large chunks. This determines how large the chunks written to disk are.
ENABLE FULL DUPLEX - enables or disables the full duplex button when you record sound. This is from the days when full duplex on Linux crashed the entire system and probably doesn't apply anymore.
RECORD IN REALTIME PRIORITY - Another carryover from when kernel 2.2.0 was first released, this eliminated latency problems on that kernel. You should never need this feature on modern systems.
INTERFACEIndex files go here - Back in the days when 4 MB/sec was unearthly speed for a hard drive, index files were introduced to speed up drawing the audio tracks. This option determines where index files are placed on the hard drive
Size of index file - Determines the size of an index file. Larger index sizes allow smaller files to be drawn faster while slowing down the drawing of large files. Smaller index sizes allow large files to be drawn faster while slowing down small files.
Number of index files to keep - To keep the index directory from becoming unruly, old index files are deleted. This determines the maximum number of index files to keep in the directory.
Delete all indexes - When you change the index size or you want to clean out excessive index files, this deletes all the index files.
Cache items - To speed up rendering, several assets are kept open simultaneously. This determines how many are kept open.
Number of CPUs - When SMP was first standardized in the Linux kernel, it was thought that duals, quads, and 8 way Xeons would soon rule the world. The number of CPUs option was introduced to devote arbitrary numbers of CPUs to rendering and compression. The speed gain is tremendous but the SMP craze seems to have died off with the AMD Athlon.
PLUGINSThe time format can be represented in any number of formats. Select a format for the time indicators here. The frame base when using hours:minutes:seconds:frames is the frame rate of the project.
Clicking in/out points does what - Broadcast 2000 not only allows you to perform editing by dragging in/out points but also defines three seperate operations which occur when you drag an in/out point. For each mouse button you select the behavior in this window. The usage of each editing mode is described in editing
Format for meter - This option allows you to select the format for all the VU meters. If you're a CS major select percentage and if you're a EE major select DB.
Min DB for meter - The minimum DB to display on a meter for EE majors.
VIDEOThis selects where Broadcast 2000 looks for plugins. It looks in two directories, the Global plugin directory and the personal plugin directory. The global plugin directory should be set by default. The personal plugin directory was originally intended to allow more flexibility in which plugins you use.
It turned out that since many plugins are required to open project files you should only store plugins in a global plugin directory. Storing plugins in a personal plugin directory causes your projects to be unreadable by anyone else.
ABOUT THE SOUND DRIVERSActual framerate being achieved - When playing back, the framerate is not always the specified framerate for the project. This displays the actual framerate being achieved during playback.
Play every frame - Broadcast 2000 drops frames to keep the video synchronized with the audio when the video can't be rendered fast enough. This option causes it to play every frame even if it means losing synchronization.
Fastest rendering, alpha channels, floating point alpha channels, bilinear interpolation - Determines the quality and hence the speed of rendering.
Fastest rendering - performs low quality scaling, and no alpha channels.
Alpha channels - performs low quality scaling and a lossy integer alpha blend.
Floating point alpha channels - performs low quality scaling and a floating point alpha blend.
Bilinear interpolation - perform a high quality scale with floating point alpha blending.
OSS - The first sound driver for Linux was developed out of the idea that you could have a single sound driver for all the UNIX platforms. OSS was the most reliable sound driver. The commercial OSS driver Supports the most soundcards and resolves most audio problems by itself.ABOUT THE VIDEO DRIVERSALSA - set to replace OSS eventually. Does the same thing as OSS but different programming language and specific to Linux. This might be supported eventually if it isn't phased out beforehand.
ESOUND - A stripped down sound driver which ran on top of OSS. This allowed playing sound over a network, mixing multiple audio sources, but lacked synchronization.
IEEE1394 - Allows you to record audio from a digital camcorder. The camcorder must be set for 16 bit 48kHz 2 channel for this to work.
Video4Linux 1 - Was developed when analog video capture boards were popping up on computers. It was intended to be a single common programming interface to all the capture boards and was designed for watching TV on a computer. Supports no hardware compression and only 2 frames of buffering. The old analog WinTV cards were the best supported.Video4Linux 2 - Was intended to replace Video4Linux 1 but for academic reasons was abandonned. Had identical functionality to Video4Linux 1 but a different programming language. Supported more than two frames of buffering.
Screen Capture - Records video from your desktop.
LML33 - A capture board from Linux Media Labs which offered hardware compression. This was a practical way of recording analog video at high framerates.
IEEE 1394 - This is the communication protocol between digital camcorders and computers. It was marketed as Firewire and ILink but more commonly IEEE 1394 in the Linux world for political reasons. This produces the highest quality of all the capture drivers.
Recording is supported but not playback to IEEE1394. Because IEEE1394 is rapidly approaching the end of its product cycle, it's unclear whether playback will ever be supported.