ACMDM_STREAM_SIZE
lParam1 = (LPARAM) pacmDSI // see below
lParam2 = (LPARAM) pacmDSS // see below
Sent to an Audio Compression Manager (ACM) driver to query recommended buffer conversion sizes for a conversion stream. This message is usually sent to an ACM driver in response to an acmStreamSize call.
- Return MMSYSERR_NOERROR if the operation is successful or an error value otherwise. The following errors are possible:
| MMSYSERR_NOTENABLED |
The driver failed to load or initialize. |
| ACMERR_NOTPOSSIBLE |
The ACMDRVSTREAMSIZE structure and query type specified information that cannot be satisfied by the driver. |
| MMSYSERR_NOTSUPPORTED |
The driver does not support the requested query type. A driver must always support the ACM_STREAMSIZEF_SOURCE and ACM_STREAMSIZEF_DESTINATION query types. |
- lParam1
- Address of the ACMDRVSTREAMINSTANCE structure for the conversion stream that the conversion size request is for.
- lParam2
- Address of the ACMDRVSTREAMSIZE structure that defines the conversion stream size query attributes.
An ACM driver must support this message if it supports the ACMDM_STREAM_OPEN message. Note that the following parameters for the ACMDM_STREAM_SIZE message will be validated before calling the driver:
- The lParam1 parameter will contain a valid pointer to an ACMDRVSTREAMINSTANCE structure with the same information as the corresponding ACMDM_STREAM_OPEN message.
- The lParam2 parameter will contain a valid pointer to an ACMDRVSTREAMSIZE structure with the proper members initialized for the requested query operation. This structure will be at least the size of the base ACMDRVSTREAMSIZE structure.
- The cbStruct member of the ACMDRVSTREAMSIZE structure will be set to at least the size, in bytes, of the base ACMDRVSTREAMSIZE structure.
- The cbSrcLength will be nonzero if the ACM_STREAMSIZEF_SOURCE flag is specified.
- The cbDstLength will be nonzero if the ACM_STREAMSIZEF_DESTINATION flag is specified.
- No invalid flag combinations will be specified in the fdwSize member.
The driver does not need to check for these conditions.
See Also
ACMDM_STREAM_CLOSE, ACMDM_STREAM_CONVERT, ACMDM_STREAM_OPEN, ACMDM_STREAM_PREPARE, ACMDM_STREAM_RESET, ACMDM_STREAM_UNPREPARE, ACMDRVOPENDESC, ACMDRVSTREAMHEADER, ACMDRVSTREAMINSTANCE, ACMDRVSTREAMSIZE