Changes between Version 10 and Version 11 of Nokia_APS_VAS_Direct


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Timestamp:
Feb 16, 2009 2:51:24 PM (15 years ago)
Author:
bennylp
Comment:

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  • Nokia_APS_VAS_Direct

    v10 v11  
    2929The whole point of APS-Direct is to enable end-to-end '''encoded audio format media flow''', that is from microphone device down to network/socket and from network/socket to the speaker device. This may sound obvious, but it has the following serious implications which will impact your application design. 
    3030 
    31 === What APS-Direct is really === 
    32  
    33   To use APS-Direct means that you're opening the sound device in codec (i.e. non-PCM) mode. You '''still have the choice''', at run-time, to open the sound device in PCM mode, if you wish, for example to make use of the PCM features in PJMEDIA such as the tone generator, or if you want to use the software codecs such as Speex or G.722 in PJMEDIA. Note that if you use PJSUA-LIB then the management of closing/re-opening the sound device using the correct codec may be done by PJSUA-LIB automatically. 
    34  
    35   To use APS-Direct also means that you are restricted to use the audio switchboard at compile time (audio switchboard will be explained later). This means that you loose the capability of mixing audio with PJSUA-LIB, as well as several other restrictions on your audio routing arrangements. 
    36  
    37  
    38 === No access to PCM data === 
    39  
    40  This may sound obvious, but it really means that many PJMEDIA features will not be available to use when the sound device is opened in codec mode (such as: tone generator, PCM WAV files, echo canceller, conference bridge mixing, software based codecs, etc.). Some of these fatures, such as EC and codecs, will use the corresponding features in the sound device hardware, but some others such as tone generator simply cannot be used unless the sound device is closed and re-opened in PCM mode. 
    41  
    42 === No mixing === 
    43  
    44   As will later be explained, we have developed a new variant of conference bridge called ''audio switchboard''. This object has the same API as the bridge, but it lacks the mixing capability of the bridge. The implication of this is you can't have two slots transmitting to the same slot in the switchboard. 
    45  
    46   So among other things, you can't have two calls with active and connected to the audio device at the same time. You can have more than one calls, but one of them must be put on-hold. 
    47  
    48  
    49 === One format rule === 
     31== What APS-Direct is really == 
     32 
     33To use APS-Direct means that you're opening the sound device in codec (i.e. non-PCM) mode. You '''still have the choice''', at run-time, to open the sound device in PCM mode, if you wish, for example to make use of the PCM features in PJMEDIA such as the tone generator, or if you want to use the software codecs such as Speex or G.722 in PJMEDIA. Note that if you use PJSUA-LIB then the management of closing/re-opening the sound device using the correct codec may be done by PJSUA-LIB automatically. 
     34 
     35To use APS-Direct also means that you are restricted to use the audio switchboard at compile time (audio switchboard will be explained later). This means that you loose the capability of mixing audio with PJSUA-LIB, as well as several other restrictions on your audio routing arrangements. 
     36 
     37 
     38== No access to PCM data == 
     39 
     40This may sound obvious, but it really means that many PJMEDIA features will not be available to use when the sound device is opened in codec mode (such as: tone generator, PCM WAV files, echo canceller, conference bridge mixing, software based codecs, etc.). Some of these fatures, such as EC and codecs, will use the corresponding features in the sound device hardware, but some others such as tone generator simply cannot be used unless the sound device is closed and re-opened in PCM mode. 
     41 
     42== No mixing == 
     43 
     44As will later be explained, we have developed a new variant of conference bridge called ''audio switchboard''. This object has the same API as the bridge, but it lacks the mixing capability of the bridge. The implication of this is you can't have two slots transmitting to the same slot in the switchboard. 
     45 
     46So among other things, you can't have two calls with active and connected to the audio device at the same time. You can have more than one calls, but one of them must be put on-hold. 
     47 
     48 
     49== One format rule == 
    5050   
    51   The sound device can only handle one format at a time, meaning that if it is currently opened with G.729 format (for one call for example), you can't feed it with PCM frames for example from the tone generator or PCM WAV files. 
    52  
    53   All PJMEDIA features that work with PCM audio will no longer work if the audio device is currently opened in codec mode. This includes the tone generator (tonegen) and WAV files. If you wish to use any of the features above, you must close the sound device and re-open it in PCM mode. 
     51The sound device can only handle one format at a time, meaning that if it is currently opened with G.729 format (for one call for example), you can't feed it with PCM frames for example from the tone generator or PCM WAV files. 
     52 
     53All PJMEDIA features that work with PCM audio will no longer work if the audio device is currently opened in codec mode. This includes the tone generator (tonegen) and WAV files. If you wish to use any of the features above, you must close the sound device and re-open it in PCM mode. 
    5454 
    5555