To generate
a WMV (*.wmv, *.asf) file, it is necessary to set the output format properly.
For that open
the "Profile Settings" dialog window (or make use of the "Properties"
window). In the Main section select "WMV, Windows Media Video"
from the "Output
Format" list:
Video
encoding parameters.
Go to the Video
section. The following parameters are available here:
Codec - the codec that will be used
for compression of the video stream. This list includes all codecs installed
on your computer that can be used for encoding video into Windows Media
Video format. These codecs are not delivered along with Watermark Master,
and we are not responsible for the quality of their work.
Encoding
mode - the video encoding mode. This parameter can take one of
the following values:
CBR - if selected,
the specified bitrate value will be constant over
the whole video encoding process. This encoding mode is useful for streaming
multimedia content on limited capacity channels since it is the maximum
(not the average) bitrate that matters. CBR would not be the optimal choice
for storage as it would not allocate enough data for complex segments
of video files (resulting in degraded quality) while wasting data on simple
segments.
Quality
VBR - if selected, the codec will encode the video stream so that
its quality will be constant over the whole
produced video file. This encoding mode can be recommended, if it is foremost
for you to get the specified quality at the output. The disadvantage of
Quality VBR encoding is that there's no way to predict the produced file
size.
Unconstrained VBR
- if selected, the codec will consider the specified bitrate
value as the average, and encode the video stream so that the quality
will be as high as possible while maintaining the average. A higher bitrate
(and therefore more storage space) will be allocated to the more complex
segments of video files while less space will be allocated to less complex
segments. Thus, actual bitrate at any point of the encoded video stream
can vary greatly from the average value.
Contrained VBR -
this mode is identical to unconstrained VBR encoding, except that you
can specify a maximum bitrate and maximum buffer window. If selected,
the codec will use the maximum values to determine how to compress the
data. If you set the maximum values high enough, constrained VBR encoding
will produce the same result as unconstrained VBR encoding.
MBR
- this mode is identical to CBR encoding, except that the produced video
will include several encoded video streams, each with different bitrate
settings. When the produced file is read, the reader will determine which
stream to use based on the available bandwidth. MBR encoding mode is useful
when you want to encode content for a variety of playback scenarios.
(Для Encoding
Mode добавить ссылки
на параметры:
Bitrate, etc)
Bitrate - the
number of bits used for representation of one second of the encoded video
stream. The higher its value, the larger the produced file size and the
higher the produced file quality. We guess the optimal value can be found
in an experimental way only. However, it is necessary to remember that
the ratio between the produced file size and quality also depends on the
selected frame
rate and frame size.
VBR quality
- the quality of the produced file. This parameter is only available for
Quality VBR encoding mode. It can take values from
0 (minimum quality) to 100 (maximum quality).
Multiple bitrate
- the sequence of bitrate values divided by semicolons. This parameter
is only available for MBR encoding mode. For example,
the following sequence of values
512;256;128
means that the produced
file will include three encoded video streams: with 512, 256 and 128 kbps
bitrate.
Key frame rate - the
rate with which key frames are created. The higher its value, the larger
the produced file size. However, a too small value may result in quality
loss and difficult navigation through the produced file.
Two-pass encoding - if enabled, the
video stream is analyzed during the first pass, and then encoded in the
second pass based on data gathered in the first pass. Two-pass encoding
can result in better quality of the produced file, because the codec can
allocate the bits more effectively within the window specified by the
buffer. However, two-pass encoding takes longer because the codec goes
through the video stream twice.
Smoothness - the minimal quality of
the produced file. In the event that the specified bitrate is not enough
to obtain the given quality, some video frames will be removed to compensate
the lack of bitrate, which in turn may result in uneven playback.
Audio encoding
parameters.
Go to the Audio
section. The following parameters are available here:
Codec - the codec that will be used
for compression of the audio stream. This list includes all codecs installed
on your computer that can be used for encoding audio into Windows Media
Audio format. These codecs are not delivered along with Watermark Master,
and we are not responsible for the quality of their work.
Audio
Format - the audio format supported by the selected audio codec.
