Audio Rematrix error going from 16ch

[Zach]

Summary of the bug:
There is a audio processing problem when going from a file with 16 audio channels down to stereo. In the files I'm working with there is only information on the first two channels.

Error Output:

[auto-inserted resampler 0 @ 03349340] [SWR @ 0293fde0] Rematrix is needed between 16 channels and 5.1(side) but there is not enough information to do it
[auto-inserted resampler 0 @ 03349340] Failed to configure output pad on auto-inserted resampler 0
Error opening filters!

ffmpeg-20140115-git-785dc14-win64-static
applies to multiple versions, take any .mov file generated by the Blackmagic Hyperdeck Shuttle and try to convert it.

[Carl Eugen Hoyos]

Please provide your failing command line together with the complete, uncut console output to make this a valid ticket.

[Zach]

Here is my terminal window. Windows doesn't seem to be letting me copy the text.

​https://drive.google.com/file/d/0B_fo81jkLciMTWVvWGZFb0MxS0U/edit?usp=sharing

[Zach]

Here is my terminal window. Windows doesn't seem to be letting me copy the text.

​https://drive.google.com/file/d/0B_fo81jkLciMTWVvWGZFb0MxS0U/edit?usp=sharing

[Carl Eugen Hoyos]

Replying to zcybercomputing:

There is a audio processing problem when going from a file with 16 audio channels down to stereo. In the files I'm working with there is only information on the first two channels.

Aren't you searching for the channelmap filter?

For future tickets: Please do not provide screen-shots (except on request), always provide your failing command line together with the complete, uncut console output pasted as text.

[Carl Eugen Hoyos]

Please reopen if there is a bug in FFmpeg that should be fixed.
The pan filter is probably also a solution for your task.

[Zach]

I figured out what the problem is. The file contains a single stream that contains 16 channels of audio. For some reason ffmpeg refuses to manipulate this type of audio stream. This type of setup is very common in broadcast video recorders, and an inability to work with it is problematic to workflow.

reference to another user with this problem.
​http://ffmpeg.org/pipermail/ffmpeg-user/2013-October/018067.html

Example file:
​https://drive.google.com/file/d/0B5GSKNa8Y3Dga05Uc09WRmtwVDg/edit?usp=sharing

Output:
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.

C:\Users\3ABN>"C:\Users\3ABN\Another Gui\ffmpeg-20140115-git-785dc14-win64-stati
c\bin\ffmpeg.exe" -i "F:\test.mov" -y -vcodec prores -profile:v 1 -acodec pcm_s1
6le -ar 48000 -ac 2 "F:\Capture0000test.mov"
ffmpeg version N-59852-g785dc14 Copyright (c) 2000-2014 the FFmpeg developers

built on Jan 14 2014 22:07:30 with gcc 4.8.2 (GCC)
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-av

isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
le-iconv --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetyp
e --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --ena
ble-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-l
ibopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libsp
eex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-aa
cenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavp
ack --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib

libavutil 52. 62.100 / 52. 62.100
libavcodec 55. 48.101 / 55. 48.101
libavformat 55. 23.103 / 55. 23.103
libavdevice 55. 5.102 / 55. 5.102
libavfilter 4. 1.100 / 4. 1.100
libswscale 2. 5.101 / 2. 5.101
libswresample 0. 17.104 / 0. 17.104
libpostproc 52. 3.100 / 52. 3.100

[mov,mp4,m4a,3gp,3g2,mj2 @ 0000000002947800] Stream #1: not enough frames to est
imate rate; consider increasing probesize
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'F:\test.mov':

Metadata:

creation_time : 2014-02-21 02:25:06

Duration: 00:00:02.74, start: 0.000000, bitrate: 81448 kb/s

Stream #0:0(eng): Video: prores (apch / 0x68637061), yuv422p10le, 720x486, 6

2874 kb/s, SAR 10:11 DAR 400:297, 29.97 fps, 29.97 tbr, 30k tbn, 30k tbc (defaul
t)

Metadata:

creation_time : 2014-02-21 02:25:06
handler_name : Apple Alias Data Handler

Stream #0:1(eng): Audio: pcm_s24le (lpcm / 0x6D63706C), 48000 Hz, 16 channel

s, s32, 18432 kb/s (default)

Metadata:

creation_time : 2014-02-21 02:25:06
handler_name : Apple Alias Data Handler

[auto-inserted resampler 0 @ 000000000525ac60] [SWR @ 0000000002940900] Rematrix

is needed between 16 channels and stereo but there is not enough information to
do it

[auto-inserted resampler 0 @ 000000000525ac60] Failed to configure output pad on

auto-inserted resampler 0

Error opening filters!

C:\Users\3ABN>

[Carl Eugen Hoyos]

Your command line is simply invalid, conversion from "16 channels" to "stereo" is not defined (and cannot be defined). Please test the pan filter and report back.
Generally, please don't change ticket priorities.

[Cigaes]

Replying to zcybercomputing:

C:\Users\3ABN>"C:\Users\3ABN\Another Gui\ffmpeg-20140115-git-785dc14-win64-static\bin\ffmpeg.exe" -i "F:\test.mov" -y -vcodec prores -profile:v 1 -acodec pcm_s16le -ar 48000 -ac 2 "F:\Capture0000test.mov"

Your file has 16 channels, you ask to make that two. How? Take the first two and drop the others? Mix the 0-7 together and 8-15 together? Mix the even ones together and the odd ones together? None of the above?

FFmpeg does not guess that kind of thing, this is not a magic trick:

[auto-inserted resampler 0 @ 000000000525ac60] [SWR @ 0000000002940900] Rematrix is needed between 16 channels and stereo but there is not enough information to do it

[Zach]

What I want to do is use the first two channels and ignore everything else. If I was doing 5.1, then they would be the first 6 channels and the rest would be discarded. This is the standard way of mapping channels when working with SDI signals (which is what produces the 16ch stream in the first place). I am sorry, I have not been able to locate part of the documentation that sufficiently explains how to structure the syntax.

[Carl Eugen Hoyos]

Did you try the link in comment:5?

[Elon Musk]

I have 10 channels sample and I cant get it work with pan filter. ffmpeg auto inserts resampler and ask for rematrix.

[Cigaes]

Do not reopen a random bug, file a new bug report with sample and full console output. You are not a newbie.

[Zach]

I am using the pan command with success, although I still think there should be better default behavior.

This is for a stereo output that lives in the first two channels.
-af pan=stereo:c0=c0:c1=c1

[Elon Musk]

I get this message:
Rematrix is needed between 10 channels and stereo but there is not enough information to do it.

[Cigaes]

That is perfectly normal. If you have a problem, ask for help on the mailing list or open a proper bug report.
As I said, you are not by far a newbie on this project, you are supposed to know how things work, so if you want help, do not behave like a newbie.

[Zach]

The AF pan should do the trick, you need to post more info to tell if this is a new problem or just something in your command implementation.