Re: [Alsa-user] Trouble with VLC and alsa channel mapping

[Richard <ric...@gm...>]

Hi,

I'm continuing to investigate that issue and did some tests with aplay, using the 5.1 wav file 
that was used to create the AAC file with I had trouble with.
It turns out that aplay also mute or lower some channels and do not play 5.1 files well.
I check the available PCM with aplay and got the following result :

[code]bash-4.2$ aplay -L
null
    Discard all samples (playback) or generate zero samples (capture)
default:CARD=SB
    HDA ATI SB, ALC889A Analog
    Default Audio Device
sysdefault:CARD=SB
    HDA ATI SB, ALC889A Analog
    Default Audio Device
front:CARD=SB,DEV=0
    HDA ATI SB, ALC889A Analog
    Front speakers
surround40:CARD=SB,DEV=0
    HDA ATI SB, ALC889A Analog
    4.0 Surround output to Front and Rear speakers
surround41:CARD=SB,DEV=0
    HDA ATI SB, ALC889A Analog
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=SB,DEV=0
    HDA ATI SB, ALC889A Analog
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=SB,DEV=0
    HDA ATI SB, ALC889A Analog
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=SB,DEV=0
    HDA ATI SB, ALC889A Analog
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=SB,DEV=0
    HDA ATI SB, ALC889A Digital
    IEC958 (S/PDIF) Digital Audio Output
hdmi:CARD=HDMI,DEV=0
    HDA ATI HDMI, HDMI 0
    HDMI Audio Output[/code]


Using the default, I get sound but not properly downmixed :

bash-4.2$ aplay -v -D default ndj_5_1_MIX.wav
Lecture WAVE 'ndj_5_1_MIX.wav' : Signed 24 bit Little Endian in 3bytes, Fréquence 48000 Hz, 
6 Canaux
Plug PCM: Route conversion PCM (sformat=S32_LE)
  Transformation table:
    0 <- 0
    1 <- 1
Its setup is:
  stream       : PLAYBACK
  access       : RW_INTERLEAVED
  format       : S24_3LE
  subformat    : STD
  channels     : 6
  rate         : 48000
  exact rate   : 48000 (48000/1)
  msbits       : 24
  buffer_size  : 8192
  period_size  : 1024
  period_time  : 21333
  tstamp_mode  : NONE
  period_step  : 1
  avail_min    : 1024
  period_event : 0
  start_threshold  : 8192
  stop_threshold   : 8192
  silence_threshold: 0
  silence_size : 0
  boundary     : 4611686018427387904
Slave: Soft volume PCM
Control: PCM Playback Volume
min_dB: -51
max_dB: 0
resolution: 256
Its setup is:
  stream       : PLAYBACK
  access       : MMAP_INTERLEAVED
  format       : S32_LE
  subformat    : STD
  channels     : 2
  rate         : 48000
  exact rate   : 48000 (48000/1)
  msbits       : 32
  buffer_size  : 8192
  period_size  : 1024
  period_time  : 21333
  tstamp_mode  : NONE
  period_step  : 1
  avail_min    : 1024
  period_event : 0
  start_threshold  : 8192
  stop_threshold   : 8192
  silence_threshold: 0
  silence_size : 0
  boundary     : 4611686018427387904
Slave: Direct Stream Mixing PCM
Its setup is:
  stream       : PLAYBACK
  access       : MMAP_INTERLEAVED
  format       : S32_LE
  subformat    : STD
  channels     : 2
  rate         : 48000
  exact rate   : 48000 (48000/1)
  msbits       : 32
  buffer_size  : 8192
  period_size  : 1024
  period_time  : 21333
  tstamp_mode  : NONE
  period_step  : 1
  avail_min    : 1024
  period_event : 0
  start_threshold  : 8192
  stop_threshold   : 8192
  silence_threshold: 0
  silence_size : 0
  boundary     : 4611686018427387904
Hardware PCM card 0 'HDA ATI SB' device 0 subdevice 0
Its setup is:
  stream       : PLAYBACK
  access       : MMAP_INTERLEAVED
  format       : S32_LE
  subformat    : STD