MediaPortal Audio renderer - better video playback quality (1 Viewer)

red5goahead

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  • November 24, 2007
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    Could be usefull an hardware survery poll to know what kind of audio equipment the MP users have? Might you propose in home - page.
     

    tourettes

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  • January 7, 2005
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    New version available.

    I guess few people have been awaiting this to be released -> https://forum.team-mediaportal.com/637138-post3.html

    First test relase with following highlights:

    • Multichannel support
    • On-the-fly AC3 encoding for SPDIF users
    • Support for non 16 bit samples (24 bit integer, 32 bit integer and 32 bit float)
    • Improved the logging for debugging - log more stream events, used audio decoder etc.

    Fixes:

    • When buffer underrun happens don't discard the available data
    • WASAPI shared mode was not working
    • Missing support for the device latency (for A/V sync) - implemented for WASAPI only
    • Improved A/V sync for pause / seeking / start of playback
    • Fixed some wrong logging of dropped audio samples
    • Fixed device period instructions - logging change only
    • Added logging for the default WASAPI audio device when it is used

    Some new settings:

    EnableAC3Encoding

    Enables AC3 (Dolby Digital on-the-fly encoding for SPDIF). Disabled by default.

    AC3bitrate

    Bitrate setting for the AC3 encoding. Default value is 448 kbps, valid values are 192, 224, 256, 320, 384, 448, 512, 576, 640.


    Some notes:

    1) NVIDIA GPU / HDMI drivers wont work with the audio renderer in WASAPI exclusive mode. This seems to be a driver bug.

    2) AC3 encoding works only WASAPI exclusive mode (shared mode cannot be ever supported - technical limitation. DirectSound might get support some day)

    3) SPDIF / AC3 supports only 32.0 / 44.1 / 48 KHz sample rates (and the audio HW must support these as well). To overcome this limitation please use ffdshow's internal resampler plugin. Resampling feature will be added to the audio renderer at some later stage. Similar limitation is affecting the WASAPI shared & exclusive mode (but not DirectSound since it has OS provided resampler, to ruin the sound quality :D). If you see 0x88890008 (AUDCLNT_E_UNSUPPORTED_FORMAT) error in the logs, please use ffdshow's resample for the time being to allow non-native HW sample rates to be used.
     

    Henkie Flits

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    Awesome Tourettes! I'm going to try this one again.
    In a few weeks I'm going to reinstall and will test it on a clean system.

    One question: how do the new features affect installation and codec setup? How to setup to use properly? Thanks!
     

    emphatic

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  • August 25, 2006
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    1) NVIDIA GPU / HDMI drivers wont work with the audio renderer in WASAPI exclusive mode. This seems to be a driver bug.

    2) AC3 encoding works only WASAPI exclusive mode (shared mode cannot be ever supported - technical limitation. DirectSound might get support some day)

    So, to use AC3 encoding with an NVIDIA GPU, I can't use the HDMI. But how about if I have a DVI output -> HDMI for video, can I use my (sadly Creative) soundcard without related NVIDIA issues?

    Thanks for your excellent work!
    Emph
     

    elliottmc

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  • August 7, 2005
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    Hi,

    Looking okay on version 6 in a quick test.

    However, I cannot change the sound volume or mute it. The volume/mute OSD appears, but the volume does not change.

    Mark
     

    tourettes

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    However, I cannot change the sound volume or mute it. The volume/mute OSD appears, but the volume does not change.

    WASAPI exclusive mode doesn't allow vvolume controlling to be done by the drivers / OS mixer / audio HW. It would have to be implemented by the audio renderer. Since it will lower the audio quality (singnal to noise ration drops the amount the volume is lowered) I wont list that feature as a high priority one. Changing the volume on amp is always preferred way to preserve the sound quality (all other audio renderers are falling into this case as well).
     

    tourettes

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  • January 7, 2005
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    So, to use AC3 encoding with an NVIDIA GPU, I can't use the HDMI. But how about if I have a DVI output -> HDMI for video, can I use my (sadly Creative) soundcard without related NVIDIA issues?

    If you have GT2xx or similar new NVIDIA GPUs they support HDMI with 8 channel LPCM and you wont need to use SPDIF / AC3 encoding with those. Older ones have SPDIF connector in the GPUs(?) as the audio source, so you would need to use some external (motherboard for example) audio chip to provide the AC3 sound to the GPU to send it in HDMI.

    Creative card should work fine (unless there are some buggy drivers :)).
     

    elliottmc

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    However, I cannot change the sound volume or mute it. The volume/mute OSD appears, but the volume does not change.

    WASAPI exclusive mode doesn't allow vvolume controlling to be done by the drivers / OS mixer / audio HW. It would have to be implemented by the audio renderer. Since it will lower the audio quality (singnal to noise ration drops the amount the volume is lowered) I wont list that feature as a high priority one. Changing the volume on amp is always preferred way to preserve the sound quality (all other audio renderers are falling into this case as well).

    Ah, that assumes I have an amp. I just have computer speakers, so the only way I can control the volume is through the PC.

    Mark
     

    tourettes

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    One question: how do the new features affect installation and codec setup? How to setup to use properly? Thanks!

    Foe codec setup, no forcing to stereo mode should be required. For example if you have 5.1 channel setup you should set MPA to output as 3 front + 2 rear + LFE. For ffdshow using mixer to downmix to 2 channels shouldn't be/isn't needed anymore. Resampling for example to 48.0Khz (most compatible sample rate with different HW) should be the first step when troubleshooring some playback issues.

    Also if you are going to use the new AC3 encoding you need to have following registry settings:

    EnableAC3Encoding = 1
    EnableTimestretching = 1
    WASAPIExclusive = 1
    ForceDirectSound = 0
     

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