2

I am trying to find the number of channels in a given .mp4 file. I run mediainfo, but it shows it as 8! Basically it should either be a 2 channel, or 5.1 showing as 6. And many of my files look like this. I guess many of the channels might be filled with empty data, or something like this.

How can I say if it is really 2 or 5.1 channel? Is there any ways, maybe with other tools to d tetect hat?

Audio 
ID : 2 
Format : AAC LC SBR 
Format/Info : Advanced Audio Codec Low Complexity with Spectral Band Replication 
Commercial name : HE-AAC 
Format settings : NBC 
Codec ID : mp4a-40-2 
Duration : 6 min 34 s 
Bit rate mode : Constant 
Bit rate : 98.3 kb/s 
Channel(s) : 8 channels 
Channel layout : ? Ls Rs LFE 
Sampling rate : 48.0 kHz 
Frame rate : 23.438 FPS (2048 SPF) 
Compression mode : Lossy 
Stream size : 4.62 MiB (5%) 
Encoded date : UTC 2016-03-14 23:30:19 
Tagged date : UTC 2016-03-14 23:30:19
Tina J
  • 579

1 Answers1

2

This was fixed in mediainfo.

Audio
ID                          : 2
Format                      : AAC LC SBR
Format/Info                 : Advanced Audio Codec Low Complexity with Spectral Band Replication
Commercial name             : HE-AAC
Format settings             : NBC
Codec ID                    : mp4a-40-2
Duration                    : 1 min 3 s
Bit rate mode               : Constant
Bit rate                    : 98.3 kb/s
Channel(s)                  : 8 channels
Channel layout              : C L R Lw Rw Ls Rs LFE
Sampling rate               : 48.0 kHz
Frame rate                  : 23.438 FPS (2048 SPF)
Compression mode            : Lossy
Stream size                 : 757 KiB (5%)
Encoded date                : UTC 2016-04-08 00:54:59
Tagged date                 : UTC 2016-04-08 00:54:59

You can also use ffmpeg:

  Stream #0:1(und): Audio: aac (HE-AAC) (mp4a / 0x6134706D), 48000 Hz, 7.1(wide), fltp, 98 kb/s (default)
    Metadata:
      creation_time   : 2016-04-08T00:54:59.000000Z
      handler_name    : SoundHandler
      vendor_id       : [0][0][0][0]

But there are many bugs in ffmpeg, so be careful. https://trac.ffmpeg.org/query?status=!closed&keywords=~aac

Encoder from apple or its clone https://github.com/nu774/qaac are also much better.

Валерий Заподовников
  • 395