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Frequently asked questions

  1. Can I use extended .avi files with Windows Media Encoding Script?

    Yes. Windows Media Encoding Script supports the extended .avi format specification and can encode .avi files that are larger than 2 gigabytes (GB).

  2. What kind of compression is applied if I don't specify a profile or other options in my encoding command?

    Windows Media Encoding Script uses the following defaults for each setting: Windows Media Audio Standard 9 and Windows Media Video 9 codecs; one-pass CBR encoding; the frame rate and frame height and width match that of the input source; one channel; an audio sampling rate of 44,100 Hz; a delay buffer of 3,000 milliseconds; smoothness setting of 75; key frame distance of 10 seconds; and the audio and video bit rates of 64 and 250 kilobits per second (Kbps), respectively.

  3. Can I transcode compressed Windows Media files with .wma and .wmv file name extensions to achieve a different bit rate?

    Yes. However, you will have better results if you encode the original source file again and specify the bit rate you want with the –v_bitrate option for video or the –a_setting option for audio.

  4. I set the –v_bitrate in one- and two-pass CBR and bit rate-based VBR modes (-v_mode 0, 1, and 3), and the bit rate of the compressed clip is significantly lower than what I specified. Is this an error?

    No. If the clip, or some segment of the clip, is easy to encode for the target bit rate (for example, the bit rate setting is very high and the resolution is low), the codec does not require all of the available bandwidth to compress the content.

  5. I set the –v_bitrate in bit rate-based VBR mode (-v_mode 3), and the bit rate of the compressed clip is significantly higher than what I specified. Is this an error?

    No. Frames are not dropped when you encode content by using the –v_mode 3 option. If the clip, or some segment of the clip, is difficult to encode for the target bit rate (for example, the bit rate setting is low and the resolution is high), the codec does require more bandwidth to compress the content.

  6. In what order does Windows Media Encoding Script clip, preprocess, and resize my content?

    Clipping is the first step and is performed on the source. By clipping first, the encoding process is more efficient because you eliminate any unwanted portions of the video before encoding them. Preprocessing, such as applying deinterlacing or inverse telecine filters comes second, followed by setting the output size of the encoded video.

  7. Can I use Windows Media Encoding Script to encode a multiple-bit-rate (MBR) file so I can stream my content to users who have various connection speeds?

    No. Windows Media Encoding Script does not support MBR encoding. Windows Media Encoder does support MBR encoding and includes several profiles to suit your needs.

  8. I used the -v_quality setting to set my image quality to 95 and then 96. I achieved the same result with both settings. Is this normal?

    Yes. Some of the -v_quality settings are mapped internally to the same image quality value. To see a change in your image quality, increase or decrease your -v_quality setting by larger increments.

  9. The statistic showing the amount of buffer that was used during my encoding session differs from the -v_buffer value that I set. Why?

    If you set a large buffer but are encoding content that is not very complex, the codecs may not use all of the buffer space that was allocated. In the rare case that you set a very small buffer, the codecs may need a larger buffer space than what you allocated. The effective buffering delay is either the buffer that you set or the buffer the codecs actually used, whichever is larger.

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