QVidium QVSD - Manual (Page 42)

User‟s Manual v.3 QVidium
®
QVSD H.264 SD Video Codec™
Copyright 2011 QVidium
®
Technologies, Inc.Page 42 of 53
25 fps for PAL video format. If you need to produce lower video bitrates, and reducing the
resolution is not sufficient or undesired, you can use this feature to sacrifice frame rate for
lower bitrates.
Video Encoding: The H.264 SD Video Codec™ digitizes and converts an analog video
input signal according to the ITU-R.BT-656 standard, performs a 4:2:2 to 4:2:0
conversion and compresses the digitized video using either the MPEG-2 video encoding
standard (MP@ML, ISO/IEC-13818-2) or MPEG4-AVC (H.264) high profile
compression, depending upon your selection.
We suggest that you select H.264 compression. The QVSD codec incorporates High
Profile, Level 4.0 to 4.1 MPEG4-AVC (part 10) video encoding. This nearly always
produces better video 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 QVSD 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 SD 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 Composite and S-Video video inputs.
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.