QVidium QVMP2C-1011 - Manual (Page 32)

User’s Manual v.28 QVidium™ MPEG2+4 Codec
13
Appendix
13.1 Appendix A: Encoder Configuration Parameters
This section explains the parameters related to the analog input signals and encoding
settings and how they relate to the operation of the encoder and error correction and
network transport setup.
Stream Transport Type (Transport or Program): Specifies whether the multiplex the
video and audio streams as a single MPEG-2 Transport Stream or an MPEG-2 Program
Stream. In both cases, the MPEG-2 Stream Type is independent of the video and audio
encoding. You can select either transport type with any of the other audio and video
parameters, including choice of video encoding.
Transport Streams are more robust, while Program Streams reduce transport throughput
overhead. DVDs and other recorded material typically use Program Stream, while
normally streaming video uses Transport Stream. Transport Stream includes slightly
higher throughput overhead by repeating stream information at regular intervals so that a
decoder can more easily recover when an IP network loses part of the stream. However,
when a network link has very limited bandwidth, you can select Program Stream to lower
the stream bitrate.
Transport Stream Bit Rate: Total constant bit rate for aggregate multiplexed multimedia
stream. The transport stream bit rate includes the video program, audio program and
program stream information. The encoder automatically sets the video encoding bit rate
taling into account the transport stream rate minus the audio and program stream
information rates. The transport stream bit rate is specified in bits per second and can
range from 2.5 Mbps to 7.5 Mbps for 720x480, 704x480, 640x480, 720x576 and 704x576
resolutions or can range from 600Kbps to 7.5 Mbps for 352x240, 320x240 and 352x288
resolutions. The higher the bit rate, the better the video quality.
Audio Bit Rate (compressed): The audio bit rate determines encoding audio quality and
allows you to trade off audio throughput for quality. The audio bit rate can be set to one of
32,000, 64,000, 128,000, 192,000, 256,000 or 384,000 bits per second. Increasing the
audio bitrate, up to a maximum value of 384 Kbps increases the audio fidelity. Regardless
of the audio signal level on either channel, selecting an audio bitrate of 64 Kbps or higher
will always force the encoder to send 2 channels of audio (stereo audio). Each audio
channel uses one-half of the selected audio bitrate. Selecting 32 Kbps for the audio bitrate
will discard the right audio channel (red connector) and only send the left channel of
audio. Selecting zero (0) will disable the transmission of audio altogether. The MPEG2+4
IP Codec encodes audio using MPEG-1 Layer II encoding.
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