Hi, Greg, You are right. I am using that guide to code a HW audio device. I don't have problems with the dummy PCMs illustrated in that guide. As you know, HW audio device/decoder buffers encoded audio frames and feedbacks correspondent dummy PCMs. I did exactly like that.
Later, I found that HXAudioSession pushes down more PCMs to device than the dummy PCMs decoder feed backed. It is not clear to me what is case HXAudioSession will insert silent PCMs into the stream. Maybe packet loss? If so, how does HW audio device know that PCMs pushed down is actually faked silence? -- this is very important for HW device/decoders for they don't accept silent PCMs. You mentioned as "there are a few places in hxaudses.cpp where the PCM data is silenced and/or inserted into the audio stream". Would you please explain those places? It seems silent PCMs are generated in CHXAudioStream, which is controlled by HXAudioSession. Is it right? Thanks, Gang Shen -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of ext Greg Wright Sent: Monday, August 15, 2005 3:45 PM To: Shen Gang.1 (Nokia-TP-MSW/Dallas) Cc: [email protected] Subject: Re: [Audio-dev] HXAudioSession & CHXAudioStream [EMAIL PROTECTED] wrote: > Hi, > > When I program a DSP audio device, I found something interesting. > When no data in the buffer (CHXAudioStream), HXAudioSession still pushes > fake PCMs down to audio device(::CheckToPlayMoreAudio). Those PCMs are > generated by CHXAudioStream. Since DSP device has to buffer every > encoded frame in a seperate queue, it is disturbing to receive > ::Write() with extra PCMs. Although I made a workaround for that, > I am wondering why HXAudioSession & CHXAudioStream are designed in > that way. Could anyone kindly explain a little bit? > > Thanks, > > Gang Shen Could you explain a little more about what it is you are doing exactly? From the above it sounds like you have a hardware decoder for some audio stream. Is that correct? If so, have you read the "Hardware Decoder Integration Guide": https://client.helixcommunity.org/2004/devdocs/dsp_inte It will talk a bit about where some of this 'dummy PCM' can come from and why it is used. If the above is not the case, then there are a few places in hxaudses.cpp where the PCM data is silenced and/or inserted into the audio stream. I would need to know more about your specific playback scenario to tell you more however. Let me know if you have any other questions, --greg. _______________________________________________ Audio-dev mailing list [email protected] http://lists.helixcommunity.org/mailman/listinfo/audio-dev _______________________________________________ Audio-dev mailing list [email protected] http://lists.helixcommunity.org/mailman/listinfo/audio-dev
