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When you implement a CBR or VBR encoding mode, the only required parameter is the -v_mode or -a_mode option for the mode. However, each mode has optional parameters you can specify. Default values are used if you do not specify the parameter.
The following table summarizes the command-line options that you can use when you implement a CBR or VBR encoding mode for video content.
| Mode | Optional parameters |
| One-pass CBR (-v_mode 0) | -v_bitrate and -v_buffer |
| Two-pass CBR (-v_mode 1) | -v_bitrate and -v_buffer |
| Quality-based VBR (one-pass, -v_mode 2) | -v_quality (the default is 95) |
| Bit rate-based VBR (two-pass, -v_mode 3) | -v_bitrate |
| Peak bit rate-based VBR (two-pass, -v_mode 4) |
-v_bitrate, -v_peakbitrate, and -v_peakbuffer |
The following table summarizes the command-line options that you can use when implementing a CBR or VBR mode for audio content.
| Mode | Optional parameters |
| One-pass CBR (-a_mode 0) | -a_setting |
| Two-pass CBR (-a_mode 1) | -a_setting |
| Quality-based VBR (one-pass, -a_mode 2) | -a_setting (see the following paragraphs for more information) |
| Bit rate-based VBR (two-pass, -a_mode 3) | -a_setting |
| Peak bit rate-based VBR (two-pass, -a_mode 4) |
-a_setting, -a_peakbitrate, and -a_peakbuffer |
You can mix encoding modes in a session. For example, you can use two-pass CBR encoding for your audio and quality-based VBR encoding for your video.
When you use quality-based VBR encoding for audio, you can use -a_setting to represent the target quality by using the format Qvalue_samplerate_channel. The default is Q75_44_2, unless you also specify the Windows Media Audio 9 Professional codec, in which case the default is Q75_44_2_24. For example:
cscript.exe wmcmd.vbs –input C:\My-songs\Song1.wav –output C:\My-songs-coded\Song1.wma -a_codec WMA9PRO -a_mode 2 –a_setting Q98_48_2_24You also have the option of using the Windows Media Audio 9 Lossless codec, which requires quality-based VBR encoding at a quality setting of 100. The default value for -a_setting is Q100_44_2_16. The following example illustrates how to set up a command that specifies lossless compression at a sampling rate of 48 kHz, two channels, and 24-bit encoding:
cscript.exe wmcmd.vbs –input C:\My-songs\Song1.wav –output C:\My-songs-coded\Song1.wma -a_codec WMA9LSL -a_mode 2 –a_setting Q100_48_2_24