Re: [Alsa-user] Surround over spdif

[Kyle H. <kyl...@gm...>]

Interesting, I don't have that audio filter.  Perhaps it isn't
compiled into my build of mplayer (ubuntu 8.10, 1.0rc2-4.3.2)

Do you have ffmpeg installed?  It looks like that may be your problem.

Kyle

On Wed, Jan 28, 2009 at 9:00 AM, Floris <jkf...@dd...> wrote:
> Is there a way to encode a file on the fly?
>
> I tried the -af lavcac3enc option in mplayer, but I get an error:
>
>    $mplayer chan-id.wav -ao alsa:device=spdif -af lavcac3enc=1
>    MPlayer dev-SVN-r26940
>    CPU: Intel(R) Pentium(R) 4 CPU 3.60GHz (Family: 15, Model: 4,
> Stepping: 3)
>    CPUflags:  MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1
>    Compiled with runtime CPU detection.
>
>    Playing chan-id.wav.
>    Audio file file format detected.
>
> ==========================================================================
>    Opening audio decoder: [pcm] Uncompressed PCM audio decoder
>    AUDIO: 44100 Hz, 6 ch, s16le, 4233.6 kbit/100.00% (ratio:
> 529200->529200)
>    Selected audio codec: [pcm] afm: pcm (Uncompressed PCM)
>
> ==========================================================================
>    Audio LAVC, couldn't find encoder for codec ac3.
>    [libaf] Couldn't create or open audio filter 'lavcac3enc'
>    Error at audio filter chain pre-init!
>
> but mplayer -af help will show lavac3enc
>
> ...
>  extrastereo    : Extra stereo
>  lavcac3enc     : runtime encode to ac3 using libavcodec
>  lavcresample   : Sample frequency conversion using libavcodec
> ...
>
>
> Floris
>
> Kyle Husmann schreef:
>> Floris,
>>
>> From what I understand, you can fit only 2 uncompressed audio channels
>> over a spdif connection.  In order to handle more channels, it must be
>> compressed and then transferred as a data stream, like DTS or AC3.
>>
>> Kyle
>>
>> On Wed, Jan 28, 2009 at 7:51 AM, Floris <jkf...@dd...> wrote:
>>
>>> Maybe a simple question, but is it possible to
>>> play a 6 channel wav file over a spdif connection?
>>>
>>>
>>> $aplay -L
>>>
>>> ...
>>> iec958:CARD=Audigy2,DEV=0
>>>    Audigy 2 ZS [2001], ADC Capture/Standard PCM Playback
>>>    IEC958 (S/PDIF) Digital Audio Output
>>> ...
>>>
>>> sample file
>>> http://www.halfgaar.net/media/chan-id.zip
>>>
>>> $aplay -D iec958 chan-id.wav
>>> Playing WAVE 'chan-id.wav' : Signed 16 bit Little Endian, Rate 44100 Hz,
>>> Channels 6
>>> aplay: set_params:923: Channels count non available
>>>
>>> $mplayer chan-id.wav -ao alsa:device=spdif -channels 6
>>> MPlayer dev-SVN-r26940
>>> CPU: Intel(R) Pentium(R) 4 CPU 3.60GHz (Family: 15, Model: 4, Stepping: 3)
>>> CPUflags:  MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1
>>> Compiled with runtime CPU detection.
>>>
>>> Playing chan-id.wav.
>>> Audio file file format detected.
>>> ==========================================================================
>>> Opening audio decoder: [pcm] Uncompressed PCM audio decoder
>>> AUDIO: 44100 Hz, 6 ch, s16le, 4233.6 kbit/100.00% (ratio: 529200->529200)
>>> Selected audio codec: [pcm] afm: pcm (Uncompressed PCM)
>>> ==========================================================================
>>> AO: [alsa] 44100Hz 2ch s16le (2 bytes per sample)
>>> Video: no video
>>> Starting playback...
>>> A:   6.2 (06.2) of 6.0 (06.0)  0.2%
>>>
>>> aplay refuse to play the file while mplayer downmix the file and will
>>> only play the front left and right channels
>>>
>>> Any dts or dolby digital dvd will play fine with mplayer -ao
>>> alsa:device=spdif -afm hwac3.
>>>
>>> floris
>>>
>>>
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