Probleme with BASS_Mixer_StreamAddChannel

[kafffee]

@Ian

Okay, that's a good thing, so far I have just used .StreamCreateFile for my jingles.

What would be the best thing to start a track's (not a sample) playback, though, with least possible latency? I've experienced a little delay on slow computers when I start playback. Would you pick the overload that loads the stream into memory first or the one that plays directly from the file? Respectively any other guesses to accelerate that?

[Ian @ un4seen]

What would be the best thing to start a track's (not a sample) playback, though, with least possible latency? I've experienced a little delay on slow computers when I start playback. Would you pick the overload that loads the stream into memory first or the one that plays directly from the file? Respectively any other guesses to accelerate that?

If you're creating the stream some time in advance (ie. there's a delay between the BASS_StreamCreateFile and BASS_ChannelPlay/Start calls) then you could also call BASS_ChannelUpdate in advance so that there's some decoded data ready to play immediately. Note BASS_ChannelUpdate is only applicable when using normal BASS playback (eg. not through a mixer).

[kafffee]

@Ian

Okay, I am using a mixer. So what would you recommend? The overload that loads the file into memory and then plays back or the one that plays back directly from the file?

What about this BASS_ASYNCFILE flag? It sounds like a good idea... Do I have to consider anything when using that?

[Ian @ un4seen]

How much of a delay are you getting when you start playback, and is it every time or only sometimes? Is there less delay when not using a mixer? When playing through a mixer, the mixer's playback buffer will add latency, but you can disable that via the BASS_ATTRIB_BUFFER setting:

Code Select Expand

BASS_ChannelSetAttribute(mixer, BASS_ATTRIB_BUFFER, 0); // disable playback buffering

You can give the BASS_ASYNCFILE option a try (on the source streams) to see if it helps. It's mostly helpful for files on slow storage media.

[Phil75]

Hello 

Finally the solution of adding "Thread.Sleep(50)" to remove the "Clicks" does not work.
Additionally, it adds a noticeable delay when playing the piano.
I tried something else.

I add the Sample this way by specifying "Max = 1" :

Code Select Expand

hSampleTest = Bass.BASS_SampleLoad("D:\Sample.wav", 0, 0, 1, BASSFlag.BASS_DEFAULT Or BASSFlag.BASS_SAMPLE_FLOAT)
Then I use a Button to do the test (normally I use the data that comes from the Midi input. "NoteOn" and "NoteOff").

Instead of retriggering the Sample with "BASS_ChannelSetPosition" with the previously stored Channel Handle, I tried to do this:

Code Select Expand

Private Sub Button1_MouseDown(sender As Object, e As MouseEventArgs) Handles Button1.MouseDown

hChannelTest = Bass.BASS_SampleGetChannel(hSampleTest, BASSFlag.BASS_STREAM_DECODE Or BASSFlag.BASS_SAMCHAN_STREAM)
BassMix.BASS_Mixer_StreamAddChannel(hMixer, hChannelTest, BASSFlag.BASS_DEFAULT)

End Sub

Private Sub Button1_MouseUp(sender As Object, e As MouseEventArgs) Handles Button1.MouseUp

Bass.BASS_ChannelSlideAttribute(hChannelTest, BASSAttribute.BASS_ATTRIB_VOL, 0F, 1000.0F)

End Sub
and it seems to be working fine. There are no more "Clicks" and the sound gradually stops.

But I noticed, by regularly consulting "BassMix.BASS_Mixer_StreamGetChannelCount(hMixer)",
that the number of hChannels increased with each "click" on the button.

If I add the function "BASS_Mixer_Channel Remove(hChannelTest)", obviously the sound stops abruptly.

Code Select Expand

Bass.BASS_ChannelSlideAttribute(hChannelTest, BASSAttribute.BASS_ATTRIB_VOL, 0F, 1000.0F)
BassMix.BASS_Mixer_ChannelRemove(hChannelTest)
Is there a solution to my problem?

[Phil75]

I added a timer with this code and it seems to work. But I don't know if it will be enough :

Code Select Expand

        Dim ListChannels() As Integer
        Dim i As Short

        ListChannels = BassMix.BASS_Mixer_StreamGetChannels(hMixer)

        For i = 0 To ListChannels.Length - 1
            Select Case BassMix.BASS_Mixer_ChannelIsActive(ListChannels(i))
                Case BASSActive.BASS_ACTIVE_PAUSED, BASSActive.BASS_ACTIVE_STALLED, BASSActive.BASS_ACTIVE_STOPPED
                    BassMix.BASS_Mixer_ChannelRemove(ListChannels(i))
            End Select
        Next i


[Ian @ un4seen]

The issue there is that each BASS_SampleGetChannel(BASS_SAMCHAN_STREAM) call is creating a new stream, and they aren't being freed. To fix that, try including the BASS_STREAM_AUTOFREE flag in the BASS_Mixer_StreamAddChannel call and using value=-1 in the BASS_ChannelSlideAttribute(BASS_ATTRIB_VOL) call, so that the source ends after fading-out and then gets freed:

Code Select Expand

Private Sub Button1_MouseDown(sender As Object, e As MouseEventArgs) Handles Button1.MouseDown
hChannelTest = Bass.BASS_SampleGetChannel(hSampleTest, BASSFlag.BASS_STREAM_DECODE Or BASSFlag.BASS_SAMCHAN_STREAM)
BassMix.BASS_Mixer_StreamAddChannel(hMixer, hChannelTest, BASSFlag.BASS_STREAM_AUTOFREE) ' auto-free source
End Sub

Private Sub Button1_MouseUp(sender As Object, e As MouseEventArgs) Handles Button1.MouseUp
Bass.BASS_ChannelSlideAttribute(hChannelTest, BASSAttribute.BASS_ATTRIB_VOL, -1, 1000.0F) ' fade-out and end
End Sub


[Phil75]

@Ian Thanks for the reply.

But if I add "BASSFlag.BASS_STREAM_AUTOFREE", hChannel = 0

Code Select Expand

hChannel = Bass.BASS_SampleGetChannel(hSample, BASSFlag.BASS_STREAM_DECODE Or BASSFlag.BASS_SAMCHAN_STREAM Or BASSFlag.BASS_STREAM_AUTOFREE)
BASS_ErrorGetCode = BASS_ERROR_NOTAVAIL "The BASS_STREAM_AUTOFREE flag cannot be combined with the BASS_STREAM_DECODE flag"

If i remove BASSFlag.BASS_STREAM_DECODE, BASS_Mixer_StreamAddChannel return False

BassMix.BASS_Mixer_StreamAddChannel(hMixer, hChannel, BASSFlag.BASS_DEFAULT Or BASSFlag.BASS_MIXER_CHAN_PAUSE)

[Phil75]

Sorry, I added "BASS_STREAM_AUTOFREE" in "BASS_SampleGetChannel" instead of "BASS_Mixer_StreamAddChannel" 

Everything works very well