No Audio for AC3 codec

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SMPlayer gives me no sound when trying to open this file, on both tracks. Other plaers, like Any Video Converter or AllPlayer does not have problem with this movie, but AllPlayer cannot change tracks, I guess it is normal, very old player. I have upgraded SMP to 14.9.0, but no luck, still no sound.
Format : Matroska
Format version : Version 2
File size : 2.27 GiB
Duration : 1h 52mn
Overall bit rate : 2 908 Kbps
Encoded date : UTC 2013-03-04 15:55:07
Writing application : mkvmerge v4.4.0 ('Die Wiederkehr') realizado en Oct 31 2010 21:52:48
Writing library : libebml v1.0.0 + libmatroska v1.0.0
Attachment : Yes / Yes / Yes / Yes / Yes

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.0
Format settings, CABAC : Yes
Format settings, ReFrames : 4 frames
Codec ID : V_MPEG4/ISO/AVC
Duration : 1h 52mn
Bit rate : 2 338 Kbps
Width : 1 920 pixels
Height : 816 pixels
Display aspect ratio : 2.35:1
Frame rate mode : Constant
Frame rate : 23.976 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.062
Stream size : 1.83 GiB (80%)
Title : axis
Writing library : x264 core 128 r2216 198a7ea
Encoding settings : cabac=1 / ref=3 / deblock=1:-1:-1 / analyse=0x3:0x113 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.15 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-3 / threads=6 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=crf / mbtree=1 / crf=26.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
Default : Yes
Forced : No

Audio #1
ID : 2
Format : AC-3
Format/Info : Audio Coding 3
Mode extension : CM (complete main)
Format settings, Endianness : Big
Codec ID : A_AC3
Duration : 1h 52mn
Bit rate mode : Constant
Bit rate : 256 Kbps
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 KHz
Bit depth : 16 bits
Compression mode : Lossy
Stream size : 205 MiB (9%)
Title : español
Default : Yes
Forced : No

Audio #2
ID : 3
Format : AC-3
Format/Info : Audio Coding 3
Mode extension : CM (complete main)
Format settings, Endianness : Big
Codec ID : A_AC3
Duration : 1h 52mn
Bit rate mode : Constant
Bit rate : 256 Kbps
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48.0 KHz
Bit depth : 16 bits
Compression mode : Lossy
Stream size : 205 MiB (9%)
Title : english
Default : No
Forced : No

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I have just tried to run this movie by the Mplayer alone, and the audio worked correctly. So, it seems to be the problem with the SMPlayer. Or there is some option that blocks the audio playback? Any other file so far worked correctly on SMPlayer, video and audio.

[rvm]

Send the mplayer log (options -> view logs) after trying to play the video with AC3.

[Fade]

OK; thanks for the tip. I have checked the logs, and there was "audio filters are disabled when using the S/PDIF output!".
After unchecking "AC3/DTS pass-through S/PDIF" thingy, the sound is being played properly. What that option is supposed to do anyway?