Alcorn Mcbride Digital Video Machine 4, User Manual

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74 Making Videos
MPEG-2 Formats
The MPEG-2 Program Stream
The DVM4 plays MPEG-2 Program Streams. This stream is a Variable or
Constant bitrate stream containing both audio and video. In order to achieve
playback of video only, you must encode an elementary stream of silent
audio that will be combined with your elementary video stream to create a
program stream.
What is a Variable Bitrate?
Unlike MPEG-1, which uses a constant bitrate, MPEG-2 supports variable
bitrate program streams. This means that the encoding process scales the
bitrate up and down depending on quality needs. A scene with a
tremendous amount of movement requires more bits than a much more still
scene.
Program Stream:
Mux Bit Rate: 10.0 Mbits/s max
The stream should be authored according to ISO 13818-1 Format
MPEG-2 Video:
SIF-NTSC: 240 lines by 352
pixels
SIF-PAL: 288 lines by 352 pixels
HalfD1-NTSC: 480 lines by 352
pixels
HalfD1-PAL: 576 lines by 352
pixels
CCIR-NTSC: 480 lines by 704(or
720) pixels
Picture Format
CCIR-PAL: 576 lines by 704(or
720) pixels
Chroma Format 4:2:0
MPEG-1 Audio (Layer I or II):
Sample Rate: 44.1 KHz or 48KHz
Emphasis: Off
Mode: Stereo
NOTE: We do not
recommend using
VBR when playing
DVM4 channels in
sync. This has been
known to cause
stuttering when video
bitrates increase too
drastically at the same
time.