Hi,
I'm doing a master's on detection of double compression on MP3 audio files. I need to extract the MDCT (Modified Discrete Cosine Transform) coefficients of MP3 file or WAV previously compressed. The related work that i found utilized the LAME MP3 ( http://sourceforge.net/projects/lame/ (http://sourceforge.net/projects/lame/) ) encoder to do that extraction, but i found it's very difficult to use for that objective. There is a minimal documentation on the file HACKING of the link. It only describes that is possible to compute the MDCT coefficients, but i don't know how to do it.
I appreciate any help
If you want to record the MDCT coefficients during encoding, I would just add an fwrite() right after the call to the MDCT and store the transformed buffer directly to disk.
If you want to record the MDCT coefficients during encoding, I would just add an fwrite() right after the call to the MDCT and store the transformed buffer directly to disk.
I'm new on understanding the code of MP3. I need to extract the MDCT coefficients before the quantization. Example: I have WAV file previously compressed. On that audio i only want to extract the MDCT coefficients before quantization or huffman encoding. I don't want to compress the audio again. I only need the coefficients of each frame separated.
Example: I have WAV file previously compressed. On that audio i only want to extract the MDCT coefficients before quantization or huffman encoding.
WAV files don't have MDCT coefficients. Do you mean you have an MP3 file rather than a WAV file? Or something else?
I don't want to compress the audio again. I only need the coefficients of each frame separated.
I don't fully understand the question, but I think the answer is to edit an [encoder/decoder] such that it saves the MDCT coefficients right [after/before] the MDCT.