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fixed buffer period calculation bug.

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changed start_time to be TimeSource()->Now().
added some helpful comments.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@1079 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
shatty 2002-09-18 06:26:44 +00:00
parent 6085f1efd6
commit 39a0622e4b
1 changed files with 20 additions and 9 deletions
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29
src/add-ons/media/media-add-ons/reader/MediaReader.cpp
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@ -108,7 +108,7 @@ void MediaReader::NodeRegistered(void)
// now we can do this
output.node = Node();
output.source.id = 0;
output.source.port = output.node.port;
output.source.port = output.node.port; // same as ControlPort();
// creates the parameter web and starts the looper thread
AbstractFileInterfaceNode::NodeRegistered();
@ -412,6 +412,9 @@ status_t MediaReader::SetBufferGroup(
return B_NO_INIT;
}
int32 count = int32(fDownstreamLatency/fBufferPeriod)+2;
fprintf(stderr," downstream latency = %lld, buffer period = %lld, buffer count = %i\n",
fDownstreamLatency,fBufferPeriod,count);
// allocate the buffers
fBufferGroup = new BBufferGroup(output.format.u.multistream.max_chunk_size,count);
if (fBufferGroup == 0) {
@ -519,17 +522,21 @@ void MediaReader::Connect(
output.destination = destination;
output.format = format;
strncpy(io_name,output.name,B_MEDIA_NAME_LENGTH-1);
io_name[B_MEDIA_NAME_LENGTH] = '\0';
io_name[B_MEDIA_NAME_LENGTH-1] = '\0';
// determine our downstream latency
media_node_id id;
FindLatencyFor(output.destination, &fDownstreamLatency, &id);
// compute the buffer period (must be done before setbuffergroup)
fBufferPeriod = int32(8000000 / 1024
fBufferPeriod = bigtime_t(1000 * 8000000 / 1024
* output.format.u.multistream.max_chunk_size
/ output.format.u.multistream.max_bit_rate);
fprintf(stderr," max chunk size = %i, max bit rate = %f, buffer period = %i\n",
output.format.u.multistream.max_chunk_size,
output.format.u.multistream.max_bit_rate,fBufferPeriod);
// setup the buffers if they aren't setup yet
if (fBufferGroup == 0) {
status_t status = SetBufferGroup(output.source,0);
@ -568,10 +575,10 @@ void MediaReader::Connect(
fInternalLatency = end - start;
fprintf(stderr,"internal latency from disk read = %i\n",fInternalLatency);
fprintf(stderr," internal latency from disk read = %i\n",fInternalLatency);
} else {
fInternalLatency = 100; // just guess
fprintf(stderr,"internal latency guessed = %i\n",fInternalLatency);
fprintf(stderr," internal latency guessed = %i\n",fInternalLatency);
}
SetEventLatency(fDownstreamLatency + fInternalLatency);
@ -688,6 +695,8 @@ void MediaReader::LatencyChanged(
fDownstreamLatency = new_latency;
SetEventLatency(fDownstreamLatency + fInternalLatency);
}
// we may have to recompute the number of buffers that we are using
// see SetBufferGroup
}
// -------------------------------------------------------- //
@ -807,13 +816,17 @@ status_t MediaReader::FillFileBuffer(
if (GetCurrentFile() == 0) {
fprintf(stderr,"<- B_NO_INIT\n");
return B_NO_INIT;
}
}
fprintf(stderr," %i buffer bytes used, %i buffer bytes available\n",
buffer->SizeUsed(),buffer->SizeAvailable());
off_t position = GetCurrentFile()->Position();
ssize_t bytesRead = GetCurrentFile()->Read(buffer->Data(),buffer->SizeAvailable());
if (bytesRead < 0) {
fprintf(stderr,"<- B_FILE_ERROR\n");
return B_FILE_ERROR; // some sort of file related error
}
fprintf(stderr," %i file bytes read at position %i.\n",
bytesRead,position);
buffer->SetSizeUsed(bytesRead);
media_header * header = buffer->Header();
header->type = B_MEDIA_MULTISTREAM;
@ -821,9 +834,7 @@ status_t MediaReader::FillFileBuffer(
header->file_pos = position;
header->orig_size = bytesRead;
header->time_source = TimeSource()->ID();
// in our world performance time corresponds to bytes in the file
// so the start time of this buffer of bytes is simply its position
header->start_time = position;
header->start_time = TimeSource()->Now();
// nothing more to say?
return B_OK;
}