User’s Manual v.15
QVidium
®
H.264 HD Video Codecs
™
Copyright 2011-2014 QVidium
®
Technologies, Inc.
Page 59 of 71
than MPEG-2 video encoding. However, we provide the option to select MPEG-2 video encoding
for backward compatibility with other devices.
Video Format:
The QVPRO Codec automatically senses and selects the correct video input
format (NTSC or PAL along with the correct resolution). NTSC captures interlaced video at 29.97
frames per second, while PAL captures interlaced video at 25 frames per second. Thus, Video
Format is not listed in the user interface.
(SD Only) Video Resolution (NTSC and PAL):
The video resolution for Standard Definition video
(D-1 resolution) is 720x480 pixels for NTSC resolution (480i) and 720x576 pixels for PAL video
format (576i). This is the resolution commonly used for DVDs and Standard Definition
broadcasting. When you need to encode the video at lower bitrates, the H.264 HD Video
Codec™
allows you to select lower CIF resolution (352x240 for NTSC and 352x288 for PAL).
Video Aspect Ratio (4:3 or 16:9):
Standard Definition NTSC video has a 4:3 aspect ratio. This is
the default setting. However, many new HD Camcorders and video mixing equipment can output a
16:9 SD video feed by squeezing the image to a 4:3 aspect ratio before outputting. Setting the
Aspect Ratio to 16:9 in the encoder sets bits in the MPEG elementary stream that tell an MPEG
decoder to stretch the incoming video stream back to a 16:9 aspect ratio. This option does not
actually change the encoding resolution. Rather, it only tells the decoder to stretch the output video
to match the original 16:9 aspect ratio.
Video Input:
This allows you to select between SDI and HDMI video inputs. The QVPRO H.264
HD Video
Codec™ requires embedded digital audio from the SDI and HDMI inputs when you
select the SDI or HDMI video input.
Closed Captioning / TeleText:
This switch enables the encoder to capture and pass through VBI
Close Captioning or TeleText (depending upon whether it senses NTSC or PAL video input,
respectively). This feature is not yet supported, but planned for a future firmware release.
Low Delay:
This mode minimizes internal buffering to reduce the end-to-end delay (encoder to
decoder) to less than 300 ms. (To be supported in a future firmware release.)
Video Filtering:
You can select this feature to add a special filter to the input video that helps
reduce noise and thereby improve compression efficiency as well as clean up the picture.
Network Parameters
The fields below relate to Ethernet/IP video transport settings.
IP Transport:
This selects the type of video IP packet encapsulation and error correction used by
the codec in generating a Video/IP stream. All packetized video transport mechanisms
encapsulate a multiplexed variable bit rate MPEG-2 transport stream.
ARQ uses QVidium’s patented error correction mechanism based on a time-constrained
selective packet retransmission algorithm, in place of FEC. It also encapsulates the video
as per COP3.2 (without the FEC) and RFC 2733. However it relies upon an upstream
channel on UDP port 7020.
RTP disables all error correction mechanisms, but still encapsulates the MPEG-2
multiplexed data according to RFC2733.
UDP is similar to the RTP transport above, but does not add the RTP header to the UDP
packets. Instead it simply encapsulates the MPEG-2 transport stream data directly into the
UDP/IP packet payload.
