2.2.4.25 LinkViewerToMacStartPlaying

The LinkViewerToMacStartPlaying message is sent by the client to request that the server start streaming the content for playback at the normal (real-time) rate.

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chunkLen
MID
openFileId
padding
position
...
asfOffset
locationId
frameOffset
playIncarnation
dwAccelBandwidth (optional)
dwAccelDuration (optional)
dwLinkBandwidth (optional)

chunkLen (4 bytes): Length of the message in chunks. A chunk is 8 bytes.

MID (4 bytes): Message ID. For this message, the value MUST be 0x00030007.

openFileId (4 bytes): A 32-bit field. This field MUST be the value of the openFileId field in the LinkMacToViewerReportOpenFile (section 2.2.4.7) message that the client previously received from the server.

padding (4 bytes): A 32-bit field. This field SHOULD be set to 0x00000000 and MUST be ignored by the receiver.<24>

position (8 bytes): A DOUBLE data type field. This field MUST be set to either the time offset in seconds from which the server is requested to start streaming the content, or to the maximum positive number for data type DOUBLE (DBL_MAX). The content is assumed to begin at time 0. For example, setting this field to 0 requests the server to stream the content from the beginning. If this field is set to the maximum positive number for data type DOUBLE, either the asfOffset field or the locationId field MUST be used to specify the starting point for playback.

asfOffset (4 bytes): A 32-bit unsigned integer. This field MUST be set to the offset, in bytes, counted from the beginning of the ASF file from which the server is requested to start streaming, or set to either 0xFFFFFFFF or 0x00000000. If this field is set to 0xFFFFFFFF or 0x00000000, then either the position or locationId field MUST be used to specify the starting point for playback.

locationId (4 bytes): A 32-bit unsigned integer. This field MUST be set to the ASF data packet number from which the server is requested to start streaming the content, or set to either 0xFFFFFFFF or 0x00000000. If this field is set to 0xFFFFFFFF or 0x00000000, then either the position field or the asfOffset field MUST be used to specify the starting point for playback.

frameOffset (4 bytes): A 32-bit field. If the server is requested to stream the content until its end, this field MUST be set to 0x00000000. Otherwise, the low-order 31 bits MUST be treated as an unsigned 31-bit integer. The low-order 31 bits MUST be set to the time position in the content at which the server is requested to stop streaming, in millisecond time units. The time position MUST be expressed either relative to the start of the content (time 0), in which case the most significant bit in the frameOffset field MUST be 0, or relative to the start position requested in this LinkViewerToMacStartPlaying message, in which case the most significant bit in the frameOffset field MUST be 1.

playIncarnation (4 bytes): A 32-bit field. It MUST be set to a value in the range 0x00000001 to 0x000000FE, inclusive.

dwAccelBandwidth (4 bytes): A 32-bit unsigned integer. If this field is present, the dwAccelDuration field MUST also be present. The dwAccelBandwidth field specifies a transmission rate, in bits per second, that the client is requesting the server to use when transmitting the amount of multimedia data specified by the dwAccelDuration field.

dwAccelDuration (4 bytes): A 32-bit unsigned integer. If this field is present, the dwAccelBandwidth field MUST also be present. The dwAccelDuration field specifies an amount of multimedia data, in millisecond units, that the client is requesting the server to transmit at the bandwidth specified by the dwAccelBandwidth field.

dwLinkBandwidth (4 bytes): A 32-bit unsigned integer. If this field is present, the dwAccelBandwidth and dwAccelDuration fields MUST also be present. The dwLinkBandwidth field specifies the client's connection bandwidth, in bits per second.