[vorbis-dev] Streaming buffers/ov_read question

[Akshay Dhalwala]

Ok, I went through the code.  Problem A was actually a stupid
calculation error on my part and a misinterpretation of how Lock works.
I have verified that the ov_read does get called (and it does).  Problem
B, I think I have fixed.  However, using my new code - I still get
garbage noise.  Nothing that is played sounds remotely like my test ogg
file.  I am stumped on this one.  This is new code I have:

The variable begPlay is initially set to true, while bStop is initially
false.

while (!eof)
        {
                if (bStop)
                        break;

                // fill more data into the buffer;
                bytes_to_read = 4096;
                while (bytes_to_read > 0)
                {
                        retVal = ov_read(&vorbisFile, pcmData + (4096 -
bytes_to_read), bytes_to_read, 0, 2, 1, &currentSection);
                        if (retVal == 0)
                        {
                                eof = true;
                                break;
                        }
                        else if (retVal < 0)
                        {
                                // Hole in data
                        }
                        else
                        {
                                bytes_to_read -= retVal;
                        }
                }

                if (eof)
                        break;
                
                lpdsBuffer->Lock(0, 4096, (void **)&ptr1, &len1, (void
**)&ptr2, &len2, DSBLOCK_FROMWRITECURSOR);
                
                memcpy(ptr1, pcmData, len1);
                
                if (ptr2 != NULL)
                {
                        memcpy(ptr2, pcmData+len1, len2);
                }

                lpdsBuffer->Unlock((void **)&ptr1, len1, (void **)&ptr2,
len2);

                if (bStop)
                        break;

                if (begPlay)
                {
                        lpdsBuffer->Play(0, 0, DSBPLAY_LOOPING);
                        begPlay = false;
                }
        }

Thanks for any help.

Akshay Dhalwala

-----Original Message-----
From: owner-vorbis-dev at xiph.org [mailto:owner-vorbis-dev at xiph.org] On
Behalf Of Monty
Sent: Saturday, July 07, 2001 10:41 AM
To: vorbis-dev at xiph.org
Subject: Re: [vorbis-dev] Streaming buffers/ov_read question

On Thu, Jul 05, 2001 at 11:36:16AM -0700, Akshay Dhalwala wrote:
> Has anyone had experience using ov_read in a thread with streaming
> directsound buffers?  i have tried the following, but it just produces
a
> repeating garbage noise.  i would appreciate some help.

"Your code is buggy".  I can spot two major problems with either of
your loops functioning as intended right off the bat.  Problem A: [I
may not be intuiting lpdsBuffer->Lock behavior properly but] it looks
like none of the Ogg code is actually getting called. Once that's
fixed (or verified working properly), Problem B: you're not adjusting
the buffer segment passed to ov_read based on bytes already read.

That's just from reading it once through.  There may be more problems
lurking; spend some time with a debugger please.

Monty

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