The VideoLAN Forums

Posted: **19 Nov 2010 16:48**

Hi everyone, my first post here.

I have some broadcast quality material (.mxf files) which contain both stereo and 5.1 surround as discrete PCM mono audio channels (PCM, 0.1 - 0.8 )

VLC can play the video, but can only play one mono audio channel at a time.

All my research thus far has led me to programs such as Eac3to which is supposed to be able to encode multiple mono audio channels to a multiplexed stream. I'm not having any success with it and in any case I'd really rather play the uncompressed audio streams than spend hours compressing audio.

Can anyone offer a suggestion as to how I might be able to get the uncompressed streams to my audio device via VLC?

Dominic

Posted: **19 Nov 2010 22:27**

so you want to play several at once?

Posted: **20 Nov 2010 14:04**

Yes that's right,

If playing back in Stereo I'd like to have audio track 1 going to Left Front, track 2 to Right Front.

If playing back in Surround sound then track 3 to LF, track 4 to RF, track 5 to Cen, track 6 to Sub, track 7 to LR and track 8 to RR

Posted: **20 Nov 2010 22:55**

slave input?

Posted: **21 Nov 2010 03:27**

Thanks for your reply,

I hadn't heard of Slave Input, so I looked around and had a play. As far as I can tell, slave will only allow one separate audio and video stream to be played together.

My problem is that the individual channels are encoded as separate streams so I'd need to be able to select six audio streams simultaneously. VLC doesn't seem to allow selecting more than one audio stream concurrently.

Perhaps an example will help. Here's the ffmpeg output for a typical file:

G:\FFMpeg\ffmpeg-0.5\ffmpeg-0.5>ffmpeg -i test.mxf
FFmpeg version 0.5, Copyright (c) 2000-2009 Fabrice Bellard, et al.
configuration: --enable-gpl --enable-postproc --enable-swscale --enable-avfilt
er --enable-avfilter-lavf --enable-pthreads --enable-avisynth --enable-libfaac -
-enable-libfaad --enable-libmp3lame --enable-libspeex --enable-libtheora --enabl
e-libvorbis --enable-libxvid --enable-libx264 --enable-memalign-hack
libavutil 49.15. 0 / 49.15. 0
libavcodec 52.20. 0 / 52.20. 0
libavformat 52.31. 0 / 52.31. 0
libavdevice 52. 1. 0 / 52. 1. 0
libavfilter 0. 4. 0 / 0. 4. 0
libswscale 0. 7. 1 / 0. 7. 1
libpostproc 51. 2. 0 / 51. 2. 0
built on Mar 16 2009 16:09:18, gcc: 4.2.4 [Sherpya]

Seems stream 0 codec frame rate differs from container frame rate: 50.00 (50/1)
-> 25.00 (25/1)
Input #0, mxf, from 'test.mxf':
Duration: 00:05:54.00, start: 0.000000, bitrate: 64917 kb/s
Stream #0.0: Video: mpeg2video, yuv422p, 1920x1080 [PAR 1:1 DAR 16:9], 50000
kb/s, 25 tbr, 25 tbn, 50 tbc
Stream #0.1: Audio: pcm_s24le, 48000 Hz, mono, s16, 1152 kb/s
Stream #0.2: Audio: pcm_s24le, 48000 Hz, mono, s16, 1152 kb/s
Stream #0.3: Audio: pcm_s24le, 48000 Hz, mono, s16, 1152 kb/s
Stream #0.4: Audio: pcm_s24le, 48000 Hz, mono, s16, 1152 kb/s
Stream #0.5: Audio: pcm_s24le, 48000 Hz, mono, s16, 1152 kb/s
Stream #0.6: Audio: pcm_s24le, 48000 Hz, mono, s16, 1152 kb/s
Stream #0.7: Audio: pcm_s24le, 48000 Hz, mono, s16, 1152 kb/s
Stream #0.8: Audio: pcm_s24le, 48000 Hz, mono, s16, 1152 kb/s
Stream #0.9: Audio: pcm_s24le, 48000 Hz, mono, s16, 1152 kb/s
Stream #0.10: Audio: pcm_s24le, 48000 Hz, mono, s16, 1152 kb/s
Stream #0.11: Audio: pcm_s24le, 48000 Hz, mono, s16, 1152 kb/s
Stream #0.12: Audio: pcm_s24le, 48000 Hz, mono, s16, 1152 kb/s
Stream #0.13: Audio: pcm_s24le, 48000 Hz, mono, s16, 1152 kb/s
Stream #0.14: Audio: pcm_s24le, 48000 Hz, mono, s16, 1152 kb/s
Stream #0.15: Audio: pcm_s24le, 48000 Hz, mono, s16, 1152 kb/s
Stream #0.16: Audio: pcm_s24le, 48000 Hz, mono, s16, 1152 kb/s
At least one output file must be specified

G:\FFMpeg\ffmpeg-0.5\ffmpeg-0.5>

Posted: **01 Dec 2010 23:18**

Ok, I can't seem to get slave input to work...

Following on from my original post, I have since demuxed all audio tracks and mixed them into a 6 channel wav (5.1) using Wavewizard.

Because of problems muxing this new audio with the original video, I decided to use slave input and play the separate video and audio files simultaneously, but I can't get it to work. I select the two files using Advanced Open File, ticking Show more options and then Play another media synchronously. When I Play the media, all I get is the audio from the first file.

Is there something I'm doing wrong?

Posted: **02 Dec 2010 17:38**

yeah I"m not sure then...

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