Vela 2000-0600, Инструкция по установке и эксплуатации

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Chapter 2 — Decoder Command Set Guide 61
DECODER Command (45h)
Use command 001Ah to resume normal playback rate. This mode is reset on a
new playback.
000D Fast Forward: This command increases the playback rate. The decoding
hardware will only display the I- and P-frames from the MPEG stream, skipping
all B-frames. Use command 001Ah to resume normal playback rate. This mode is
reset on a new playback.
NOTES: (1) Fast Forward increases the playback rate, which increases the decoder’s
demand for data; therefore, the system must be capable of handling this increased
throughput.
(2) Bit rates higher than 40Mbps may result in break-up and data underflow problems,
forcing a return to Play mode.
(3) An MPEG stream comprised only of I-frames or IP-frames cannot be fast-forwarded.
000F Pause Video/Frame Advance:
Pause (000Fh) : Stops playback on current frame, freezing the video image.
Use Resume command to resume playback.
Frame Advance (010Fh) : Once in pause mode, sending the Pause command
with bit 8 set will frame advance the number of video frames indicated in the
32 bits of data. When the 32 bits of data is 0 or 1 the decoder will frame ad-
vance by 1 video frame.
NOTE: Once the decoder has been Paused, additional MPEG data (via the write 10
command) should not be sent. If all the MPEG buffers become full while in Pause, the
next write 10 will never complete. This usually results in a SCSI command timeout from
the host adapter (initiator) which causes a Bus Reset. If more MPEG data is sent, the
application must check Mode Page 30h (via mode sense command) to be sure there is
sufficient room in the MPEG buffers (bytes 14 and 15). When Frame Advance is used,
the decoder will require additional MPEG data when advancing many frames.
0011 Flush Channel Buffer: Stops playback after all data in the decoder’s buff-
ers is used. Equivalent to
RESET BUFFER
(0021h).
0012 Resume Play (from Pause): Resumes playback after a pause.
0013 Mute Audio: Mutes the audio output.
0014 Unmute Audio: Unmutes audio output. Disabled during Fast Forward,
Slow Motion, and Pause.
111b Slowest rate (each frame is displayed eight times)
Bits 10–8 Playback Speed