Skip to main content

Notice

Please note that most of the software linked on this forum is likely to be safe to use. If you are unsure, feel free to ask in the relevant topics, or send a private message to an administrator or moderator. To help curb the problems of false positives, or in the event that you do find actual malware, you can contribute through the article linked here.
Topic: obtain spectrum after pqmf and mdct in mp3 conversion (Read 1792 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

obtain spectrum after pqmf and mdct in mp3 conversion

Hi guys,

I am currently trying to obtain the values of an audio file undergoing pqmf and mdct in mp3 conversion.
using LAME, i found that the values are stored in gfc -> sb_sample (correct me if i am wrong)

hence, i printed the values into a text file by inserting the printf command in encoder.c, after the mdct_sub48(gfc, inbuf[0], inbuf[1]) command the loop is as follows:

log = fopen("mp3_mdct.txt", "a");

for (grancounter=0;grancounter>2;grancounter++)
{
for(j=0;j<32;j++)
{
for (i=0;i<18;i++)
{
fprintf(log,"%d\t%d\t%f\n", gfc->sb_sample[0][grancounter][j]);
}
fprintf(log,"\n");
internalcounter++;

}
}

fprintf(log,"\n\n");
fclose(log);


I have tried the printing out spectrum of a low note (1Hz) and a high note (22 kHz), the spectrum was reflected correctly, however, when i tried to print out the spectrum of a note of 11 kHz, the spectrum did not appear in the middle of a granule of 576 samples.

Do point out my mistakes and correct any misconception I have
Thanx!

 
SimplePortal 1.0.0 RC1 © 2008-2021