在CBR音频编码中指定所需比特率的属性名称

Question

I'm trying to configure a "Windows Media Audio Standard" DMO codec to compress in single-pass, constant bit-rate mode (CBR). Unfortunately I can not find on the MSDN documentation how can I pass the desired bit-rate to the encoder object.

In other words, I'm looking for the equivalent of MFPKEY_RMAX which seems to identify be the desired bit-rate setting for two-pass Variable Bit-rate encoding, but for single-pass, CBR encoding.

Answer 1

Finally found it. The key I required is MF_MT_AUDIO_AVG_BYTES_PER_SECOND and is documented here :

Choose the encoding bit rate.

For CBR encoding, you must know the bit rate at which you want to encode the stream before the encoding session begins. You must set the bit rate during while you are configuring the encoder. To do this, while you are performing media type negotiation, check the MF_MT_AUDIO_AVG_BYTES_PER_SECOND attribute (for audio streams) or the MF_MT_AVG_BITRATE attribute (for video streams) of the available output media types and choose an output media type that has the average bit rate closest to the target bit rate you want to achieve. For more information, see Media Type Negotiation on the Encoder.