[MPlayer-users] AAC LC 5.1 audio not recognized by mplayer
ulion2002 at gmail.com
Sat May 3 08:18:53 CEST 2008
2008/5/3 Justin Randall <jrrandall at gmail.com>:
> Hi all,
> I can't seem to get mplayer to give me 6 channel audio playback on my
> AAC encodes. Here are the steps I take and some debug info...
> I converted a valid AC3 5.1 surround audio file to a 6 channel wave using:
> > mplayer $infile -af channels=6:6:0:0:1:1:2:4:3:5:4:2:5:3 -ao pcm:fast: -channels 6 -novideo
> and then I converted that 6 channel wave to AAC LC 5.1 using nero
> > neroAacEnc -ignorelength -q 0.38 -if $wav_file -of $aac_file
> but the resulting supposed 5.1 channel audio file is not recognized by
> mplayer. It says that FAAD cannot find the compressed input bitrate
> of the aac stream. I'm asking because while mplayer falls back to two
> channels for audio, both my PS3 and QuickTime (if you believe it)
> recognize the audio as 5.1. I can confirm that the PS3 does in fact
> put out all 6 channels over my surround system. I can only confirm
> that QuickTime recognizes the stream in it's info settings since I
> don't have surround set up on my PC (maybe that is why mplayer
> defaults to stereo?).
> Here is the printout of mplayer:
> >>mplayer test.mp4
> MPlayer Sherpya-SVN-r26446-4.2.3 (C) 2000-2008 MPlayer Team
> CPU: AMD Athlon(tm) 64 X2 Dual Core Processor 4200+ (Family: 15, Model: 43, Step
> ping: 1)
> CPUflags: MMX: 1 MMX2: 1 3DNow: 1 3DNow2: 1 SSE: 1 SSE2: 1
> Compiled with runtime CPU detection.
> Playing test.mp4.
> libavformat file format detected.
> [lavf] Video stream found, -vid 0
> [lavf] Audio stream found, -aid 1
> VIDEO: [avc1] 1280x720 24bpp 23.976 fps 0.0 kbps ( 0.0 kbyte/s)
> Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
> Selected video codec: [ffh264] vfm: ffmpeg (FFmpeg H.264)
> Opening audio decoder: [faad] AAC (MPEG2/4 Advanced Audio Coding)
> FAAD: compressed input bitrate missing, assuming 128kbit/s!
> AUDIO: 48000 Hz, 2 ch, s16le, 128.0 kbit/8.33% (ratio: 16000->192000)
> Selected audio codec: [faad] afm: faad (FAAD AAC (MPEG-2/MPEG-4 Audio) decoder)
> AO: [dsound] 48000Hz 2ch s16le (2 bytes per sample)
> Starting playback...
> VDec: vo config request - 1280 x 720 (preferred colorspace: Planar YV12)
> VDec: using Planar YV12 as output csp (no 0)
> Movie-Aspect is 1.78:1 - prescaling to correct movie aspect.
> VO: [directx] 1280x720 => 1280x720 Planar YV12
> The output of mp4box -info for the same file results in the audio
> stream being reported correctly as 6 channels on track 2.
> >>mp4box -info test.mp4
> * Movie Info *
> Timescale 600 - Duration 00:21:17.161
> Fragmented File no - 2 track(s)
> File Brand isom - version 1
> Created: GMT Sat May 03 04:53:57 2008
> File has root IOD
> Scene PL 0xff - Graphics PL 0xff - OD PL 0xff
> Visual PL: AVC/H264 Profile (0x15)
> Audio PL: AAC Profile @ Level 4 (0x2a)
> No streams included in root OD
> Track # 1 Info - TrackID 1 - TimeScale 24000 - Duration 00:21:17.067
> Media Info: Language "English" - Type "vide:avc1" - 30619 samples
> MPEG-4 Config: Visual Stream - ObjectTypeIndication 0x21
> AVC/H264 Video - Visual Size 1280 x 720 - Profile High @ Level 4.1
> NAL Unit length bits: 32
> Pixel Aspect Ratio 1:1 - Indicated track size 1280 x 720
> Track # 2 Info - TrackID 2 - TimeScale 48000 - Duration 00:21:17.162
> Media Info: Language "English" - Type "soun:mp4a" - 59867 samples
> MPEG-4 Config: Audio Stream - ObjectTypeIndication 0x40
> MPEG-4 Audio AAC LC - 6 Channel(s) - SampleRate 48000
> Synchronized on stream 1
> Does anybody have any thoughts on this or have you seen this behavior
> before? Does mplayer need to have the audio in the first stream to
> properly detect all channels? I am fairly confident I did all the
> right steps, but mplayer refuses to acknowledge 6 channel audio. Any
> advice would be appreciated on this problem.
I think mplayer can detected the 6ch, when you add '-v' as parameter
of mplayer, you will see it.
if you want mplayer output 6ch, you have to add '-channels 6' as
mplayer's parameter or add it in mplayer's config file.
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