SoftHDdevice LATM AAC 5.1 audio

  • Hi!


    Some of my channels have LATM AAC audio. Two-channel audio works fine with softhddevice. However some movies are played with 5.1 audio, still LATM AAC encoded!


    This also "works", softhddevice converts it to stereo and I can hear audio. However there is something wrong. Dialog (center channel) plays only on the left speaker. Music and effects play on both left and right, but they don't sound exactly correct either.. Perhaps the channels are picked wrong, centre->left and surround->right for example? It probably should mix them somehow, similar to ac3->stereo downmix.


    Also of course it would be nice if you could transcode to ac3, but a working stereo downmix would be a good start. :)


    I'll try to make a small recording that shows the problem..

  • I think you have a A/V Receiver and 5.1 box set connected.
    If you have connected it with SPDIF or HDMI, you should enable PCM passthrough.
    A new option till version 0.6.0.


    syslog should contain something like this: (if different please post)

    Code
    1. vdr: audio: 44100Hz supports 2 2 4 4 6 6 8 8 channels
    2. vdr: audio: 48000Hz supports 2 2 4 4 6 6 8 8 channels
    3. vdr: audio: 192000Hz supports 2 2 4 4 6 6 8 8 channels


    Johns

    Sag mir, wo die Developer sind. Wo sind sie geblieben? . . . . . . . . . . . . . . . . . . . . SoftHdDevice - A software and GPU emulated HD output device plugin.
    Sag mir, wo die Developer sind. Was ist geschehn?


    Client0: Crown CW02 MSI_C847MS-E33 Zotac_GT640_passiv Cine-S2 iMon-MCE / streamdev softhddevice
    Client1: Lian_Li_PC-Q09FB ASRock_H67M-ITX/HT I3-2100 ASUS_ENGT520_passiv / streamdev softhddevice
    Test: Lian_Li_PC-Q09R Asus C60M1-I / streamdev
    Server0: Dockstar TT-S2-3600-USB / streamdev
    Server2: Lian_Li_PC-Q07R Intel_DH61DL G620 WD20EARX 90W PicoPSU Cine-S2+DuoFlex-S2+DuoFlex-CT / streamdev / 22 Watt Verbrauch

  • Hi,


    I have hdmi connection to separate hdmi splitter, and from there spdif to the receiver. The receiver only supports 2 channels pcm, as seen in the log:


    Code
    1. audio: 44100Hz supports 2 2 2 2 2 2 2 2 channels
    2. audio: 48000Hz supports 2 2 2 2 2 2 2 2 channels
    3. audio: 192000Hz supports 0 0 0 0 0 0 0 0 channels


    So, I can't play 5.1 AAC or PCM directly..


    It seems softhddevice is using the pass-through, when I switch to the channel I get this:
    "audio/alsa: using pass-through device 'default'"


    So is softhddevice passing the raw LATM stream, or is it decoded to PCM?

  • I guess you need to deactivate passthru in the setup.conf (vdr) !?


    softhddevice.AudioPassthrough = 0


    see:
    http://www.vdr-wiki.de/wiki/index.php/Softhddevice-plugin


    Maybe you need to downsample 5.1 to 2.0 using the tipps provided in the wiki.


    BR,
    Joe

  • Hi,


    but I need pass-through for AC3.. My receiver can play AC3 and DTS 5.1.

  • The LATM AAC is decoded to 5.1 PCM by the ffmpeg library.
    Than it is mixed down by SoftHdDevice plugin to 2 channels.
    When PCM passthrough is activated no mixing is done by the plugin.


    Check if you have PCM pass-through activated in the softhddevice plugin.
    You should only activate AC3 pass-through.


    I think this is the failure,


    Johns

    Sag mir, wo die Developer sind. Wo sind sie geblieben? . . . . . . . . . . . . . . . . . . . . SoftHdDevice - A software and GPU emulated HD output device plugin.
    Sag mir, wo die Developer sind. Was ist geschehn?


    Client0: Crown CW02 MSI_C847MS-E33 Zotac_GT640_passiv Cine-S2 iMon-MCE / streamdev softhddevice
    Client1: Lian_Li_PC-Q09FB ASRock_H67M-ITX/HT I3-2100 ASUS_ENGT520_passiv / streamdev softhddevice
    Test: Lian_Li_PC-Q09R Asus C60M1-I / streamdev
    Server0: Dockstar TT-S2-3600-USB / streamdev
    Server2: Lian_Li_PC-Q07R Intel_DH61DL G620 WD20EARX 90W PicoPSU Cine-S2+DuoFlex-S2+DuoFlex-CT / streamdev / 22 Watt Verbrauch