Linux ac3 to aac

Содержание

Ubuntu – How to convert AC3 6ch audio to HE-AAC? GUI solution
Best Answer
Nero AAC Encoder usage
Nero AAC quality setting
Advice for codec and quality choice on multichannel audio
Appendix: neroAacEnc help file
ffmpeg audio format conversions
Install ffmpeg on major Linux distros
Audio conversion examples
WAV – Waveform Audio File Format
wav to mp3
wav to ogg
wav to aac
wav to ac3
OGG – Free, open standard container
ogg to mp3
ogg to wav
ogg to aac
ogg to ac3
AC3 – Acoustic Coder 3
ac3 to mp3
ac3 to wav
ac3 to aac
ac3 to ogg
AAC – Advanced Audio Coding
aac to mp3
aac to wav
aac to ac3
aac to ogg
Closing Thoughts
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Ubuntu – How to convert AC3 6ch audio to HE-AAC? GUI solution

I want to convert the audio track of a MKV file to HE-AAC (AAC+/AACplus). The audio track is AC3. But there seems no GUI for HE-AAC encoding? I only found out there is a Command Line Tool (CLI) from Nero, but I don’t know if this can do HE-AAC.

Any help? Any recommendation for a GUI that can convert AC3 to HE-AAC? Also should be able to handle surround sound (5.1/6-channels).

Best Answer

Nero AAC Encoder usage

neroAacEnc does support HE-AAC and HE-AAC v2 via -he and -hev2 parameters.

This encoder is (still?) considered to be the best encoder quality wise. Nero offers it free of charge but doesn’t give support for it. One problem you will encounter with large files like 5.1 WAV is the file size limitation. It is not due to this encoder being crippleware, but how to handle large numbers in a program. To workaround this you need to pipe the input with another program to the encoder and use the -ignorelength parameter. If you input format is already WAV the following should work:

cat $myfile | neroAacEnc -q 0.5 -he -ignorelength -if - -of $myencodedfile

You can also use avconv (formerly known as ffmpeg , now forked and with the CLI tool being renamed) to do the conversion to WAV.

avconv -i $myfile -f wav - | neroAacEnc -q 0.3 -he -ignorelength -if - -of $myencodedfile

Note that the resulting file is a MP4 with a AAC stream in a MP4 container, not a raw AAC stream. You can extract the raw stream with MP4Box from the gpac package if you want to.

Nero AAC quality setting

The quality setting depends on the profile you use. With LC-AAC you can go up to -q 1.0 . HE-ACC is limited to -q 0.5 , I think, and HE-AAC v2 even lower. This is due the techniques behind those profiles that are centered around low bitrates. Using -q 0.5 will result in a file larger than common AC3 6ch audio from a DVD, using -q 0.3 will cut the file size in half.

Advice for codec and quality choice on multichannel audio

The situation is (still?) really messy, which is why there exist no easy to use GUI like Handbrake. The most efficient codec is HE-AAC v2 but it is not well supported in Ubuntu, due to licensing/patent issues in some countries. Vorbis is good too, but less efficient. Multichannel mapping should be fixed in the latest LTS release (12.04, it wasn’t in 10.04). Leaving out MP3, AC3 comes in third place. FLAC is 4th on efficiency and the most supported lossless format. DTS is a complete looser and should be also left out, like MP3. Convert to FLAC if you can.

So if you have AC3 encoded audio, you probably leave it at that if the device and container format supports it. The chart for supported media formats on Android might be helpful.

Appendix: neroAacEnc help file

Usage: neroAacEnc [options] -if -of Where: : Path to source file to encode. The file must be in Microsoft WAV format and contain PCM data. Specify - to encode from stdin. Note that multiple input files can be specified, they will be encoded together into a single output file with chapter marks indicating source file divisions. : Path to output file to encode to, in MP4 format. ==== Available options: ==== Quality/bitrate control: -q : Enables "target quality" mode. is a floating-point number in 0. 1 range. -br : Specifies "target bitrate" mode. is target bitrate in bits per second. -cbr : Specifies "target bitrate (streaming)" mode. is target bitrate in bits per second. When neither of above quality/bitrate options is used, the encoder defaults to equivalent of -q 0.5 Multipass encoding: -2pass : Enables two-pass encoding mode. Note that two-pass more requires a physical file as input, rather than stdin. -2passperiod : Overrides two-pass encoding bitrate averaging period, : in milliseconds. : Specify zero to use least restrictive value possible (default). Advanced features / troubleshooting: -lc : Forces use of LC AAC profile (HE features disabled). -he : Forces use of HE AAC profile (HEv2 features disabled). -hev2 : Forces use of HEv2 AAC profile Note that the above switches (-lc, -he, -hev2) should not be used; optimal AAC profile is automatically determined from quality/bitrate settings when no override is specified. -ignorelength : Ignores length signaled by WAV headers of input file. Useful for certain frontends using stdin.

Источник

ffmpeg audio format conversions

The ffmpeg software is a free and open source suite of utilities that facilitate audio and video media. On Linux systems, installing ffmpeg gives us access to the ffmpeg command, which can be used to convert audio files to various types, such as wav, mp3, ogg, etc.

In this guide, we will go over the instructions to install ffmpeg on major Linux distros. Then, you’ll see various command line examples that can be used to convert between different audio formats. Use the examples below to convert your own files.

In this tutorial you will learn:

How to install ffmpeg on major Linux distros
How to use ffmpeg in audio conversion examples

Software Requirements and Linux Command Line Conventions

Category	Requirements, Conventions or Software Version Used
System	Any Linux distro
Software	ffmpeg
Other	Privileged access to your Linux system as root or via the sudo command.
Conventions	# – requires given linux commands to be executed with root privileges either directly as a root user or by use of sudo command $ – requires given linux commands to be executed as a regular non-privileged user

Install ffmpeg on major Linux distros

Before we dive into the conversion examples below, you’ll need to install ffmpeg on your system. The software is available on all major Linux distros and can be easily installed using your system’s package manager. Use the appropriate command below to install it on your own computer.

To install ffmpeg on Ubuntu, Debian, and Linux Mint:

$ sudo dnf install https://mirrors.rpmfusion.org/free/fedora/rpmfusion-free-release-$(rpm -E %fedora).noarch.rpm https://mirrors.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-$(rpm -E %fedora).noarch.rpm $ sudo dnf install ffmpeg

To install ffmpeg on CentOS, AlmaLinux, and Red Hat:

$ sudo dnf install --nogpgcheck https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm $ sudo dnf install --nogpgcheck https://mirrors.rpmfusion.org/free/el/rpmfusion-free-release-8.noarch.rpm https://mirrors.rpmfusion.org/nonfree/el/rpmfusion-nonfree-release-8.noarch.rpm $ sudo dnf install ffmpeg

To install ffmpeg on Arch Linux and Manjaro:

Audio conversion examples

Check out some of the audio conversion examples below to see how ffmpeg can convert your files to different formats. We’ve compiled some of the most common options here. Note that ffmpeg has many additional quality settings and other options. It’s recommended to check out the man page and include the necessary flags in your commands.

WAV – Waveform Audio File Format

wav to mp3

Convert wav to mp3 with ffmpeg:

$ ffmpeg -i audio.wav -acodec libmp3lame audio.mp3

wav to ogg

Convert wav to ogg with ffmpeg:

$ ffmpeg -i audio.wav -acodec libvorbis audio.ogg

wav to aac

Convert wav to acc with ffmpeg:

$ ffmpeg -i audio.wav -acodec libfaac audio.aac

wav to ac3

Convert wav to ac3 with ffmpeg:

$ ffmpeg -i audio.wav -acodec ac3 audio.mp3

OGG – Free, open standard container

ogg to mp3

Convert ogg to mp3 with ffmpeg:

$ ffmpeg -i audio.ogg -acodec libmp3lame audio.mp3

ogg to wav

Convert ogg to wav with ffmpeg:

$ ffmpeg -i audio.ogg audio.wav

ogg to aac

Convert ogg to aac with ffmpeg:

$ ffmpeg -i audio.ogg -acodec libfaac audio.aac

ogg to ac3

Convert ogg to ac3 with ffmpeg:

$ ffmpeg -i audio.ogg -acodec ac3 audio.ac3

AC3 – Acoustic Coder 3

ac3 to mp3

Convert ac3 to mp3 with ffmpeg:

$ ffmpeg -i audio.ac3 -acodec libmp3lame audio.mp3

ac3 to wav

Convert ac3 to wav with ffmpeg:

$ ffmpeg -i audio.ac3 audio.wav

ac3 to aac

Convert ac3 to aac with ffmpeg:

$ ffmpeg -i audio.ac3 -acodec libfaac audio.aac

ac3 to ogg

Convert ac3 to ogg with ffmpeg:

$ ffmpeg -i audio.ac3 -acodec libvorbis audio.ogg

AAC – Advanced Audio Coding

aac to mp3

Convert aac to mp3 with ffmpeg:

$ ffmpeg -i audio.aac -acodec libmp3lame audio.mp3

aac to wav

Convert aac to wav with ffmpeg:

$ ffmpeg -i audio.aac audio.wav

aac to ac3

Convert aac to ac3 with ffmpeg:

$ ffmpeg -i audio.aac -acodec ac3 audio.ac3

aac to ogg

Convert aac to ogg with ffmpeg:

$ ffmpeg -i audio.aac -libvorbis audio.ogg

Closing Thoughts

In this guide, we saw how to install the ffmpeg suite on major Linux distros, then use the ffmpeg command to convert audio files between different formats. Our examples contained some of the most common formats, but many more exist, and the ffmpeg software is packed with options. You can adapt our examples to your own needs, while customizing your commands with further options found in the ffmpeg man pages.

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