Hi, I'm working on implementing Trick Modes (fast forward, rewind etc) in MP3. In this context, I need to play audio at higher speeds (2x, 4x). Skipping audio samples distorts the sound (it sounds very squeaky). Is there any good way of doing this? I'm assuming time warping is what I need. If yes, could anyone suggest a good article on this? Thanks, M
Time warping of audio signals
Started by ●December 16, 2005
Reply by ●December 19, 20052005-12-19
As I have not worked on the MP3 but I have the experience in the MP4. Well on that bases I am qouating some of the points, may be, it may help you. Point 1. Are you sure that you are intilising the Reader correctly, after Skipping the x number of bytes ? Point 2. Do your application / code is pointing to the correct Chunk Number of the sample, after you skipp x numbers of bytes ? Do let us know if you have still face the problem. BTW are you following the Byte Skip or the Time Stamping to Achive the to(Foearwd) and fro (rewind) of the audio file? Regards Ranjeet On Fri, 16 Dec 2005 rajashree_g@raja... wrote : >Hi, >I'm working on implementing Trick Modes (fast forward, rewind etc) in MP3. In this context, I need to play audio at higher speeds (2x, 4x). Skipping audio samples distorts the sound (it sounds very squeaky). Is there any good way of doing this? I'm assuming time warping is what I need. If yes, could anyone suggest a good article on this? >Thanks, >M
Reply by ●December 20, 20052005-12-20
Hi,
if the pitch should change with the tempo, then you are interested in
dynamic sample rate conversion/resampling. This is basically
interpolation and filtering.
If the pitch should remain constant for different tempi, then you are
interested in time stretching/scaling. In this case, look for OLA, PSOLA
or for phase vocoder.
Note that timestretching usually produces more artifacts than resampling.
Cheers,
(a)
rajashree_g@raja... wrote:
> Hi,
>
> I'm working on implementing Trick Modes (fast forward, rewind etc) in
MP3. In this context, I need to play audio at higher speeds (2x, 4x). Skipping
audio samples distorts the sound (it sounds very squeaky). Is there any good way
of doing this? I'm assuming time warping is what I need. If yes, could
anyone suggest a good article on this?
>
> Thanks,
> M