Lossless conversion of MPEG ADTS MP3 to normal MP3

mp3

I have many MP3 audio files which are ADTS encoded. Unfortunately, my car radio doesn't support ADTS, so I need to convert them to normal MP3 files without a transport stream.

There are many people out there who asked the same question, but the only answers I found was converting to wav and then use lameenc to convert it back to MP3

I'm sure there is a way to convert these files without decoding/reencoding them.

I already experimented with ffmpeg/avconv, but the parameter -acodec copy doesn't seem to output anything different than ADTS.

I also played around with GStreamer. Funnily, I think it's the module aacparse which at least understands the format, but it's not a demuxer.

Which tool can I use for this?

$ file badfile.mp3 goodfile.mp3
badfile.mp3:  MPEG ADTS, layer III, v2,  64 kbps, 22.05 kHz, JntStereo
goodfile.mp3: Audio file with ID3 version 2.4.0

An example file can be found here (Overview)

Update:
I'm still testing, but it seems that 1) Also lame produces ADTS files and 2) ADTS is not really the problem for my car radio, it must be something different. I'm testing now with different profiles and bitrates, VBR and CBR. But it is still helpful if someone knows something more about ADTS.

Best Answer

There is no way to convert MPEG ADTS to MP3 without decoding and reencoding them. They are fundamentally different formats/encodings. Any conversion utility you use that claims to do a direct conversion is in fact doing that behind the scenes--decoding to some lossless format and reencoding to some version of MP3. With that in mind, I highly recommend sox for audio format conversions. It really isn't exaggerating when it refers to itself as the "Swiss Army Knife of Audio Manipulation." Syntax is simple: sox infile outfile, but the available options put ffmpeg to shame.

Related Solutions

How to “reencode” mp3 files

It does not answer the question in your title, but maybe there's a chance to fix the files without reencoding. For example, one common issue with incorrect lengths of MP3 files are files with variable bit rate that are not properly marked as having a variable bit rate (and programs like rhythmbox treating them as if they had a constant one). The tool vbrfix can fix those files. Another useful tool to check the MP3 file is mp3check, it also has options like --fix-headers that might repair the files (make backups of the files first!).

Search mp3 collection for songs with a certain song length

First install mp3info, it should be in the repositories of your distribution (you have not said, so I assume you are using Linux of some sort). If you have a debian-based distribution, you can do so with

sudo apt-get install mp3info

Once mp3info is installed, you can search the directory music for songs of a certain length with this command:

find music/ -name "*mp3" | 
  while IFS= read -r f; do 
   length=$(mp3info -p "%S" "$f"); 
   if [[ "$length" -ge "180" && "$length" -le "195" ]]; then 
     echo "$f"; 
   fi;  
done

The command above will search music/ for mp3 files, and print their name and length if that length is grater or equal to 180 seconds (3:00) and less than or equal to 195 seconds (3:15). See man mp3info for more details on its output format.

If you want to be able to enter times in MM:SS format, it gets a bit more complex:

#!/usr/bin/env bash

## Convert MM:SS to seconds.
## The date is random, you can use your birthday if you want.
## The important part is not specifying a time so that 00:00:00
## is returned.
d=$(date -d "1/1/2013" +%s);

## Now add the number of minutes and seconds
## you give as the first argument
min=$(date -d "1/1/2013 00:$1" +%s);
## The same for the second arument
max=$(date -d "1/1/2013 00:$2" +%s);

## Search the target directory for files
## of the correct length.
find "$3" -name "*mp3" | 
  while IFS= read -r file; do 
   length=$(mp3info -p "%m:%s" "$file"); 
   ## Convert the actual length of the song (mm:ss format)
   ## to seconds so it can be compared.
   lengthsec=$(date -d "1/1/2013 00:$length" +%s);

   ## Compare the length to the $min and $max
   if [[ ($lengthsec -ge $min ) && ($lengthsec -le $max ) ]]; then 
       echo "$file"; 
   fi; 
done

Save the script above as findmp3 and run it like this:

findmp3 3:00 3:15 music/

Best Answer

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How to “reencode” mp3 files

Search mp3 collection for songs with a certain song length

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