[Libav-user] Efficient way of sampling compressed audio

[Peter Staab]

Hi,

I am interested in using libav to create a graphical representation of audio data (simple graph with left/right channel at the moment). I have used a sliding window approach where the maximum of each window is used for plotting. This works well but is quite slow because the whole audio data has to be decoded using avcodec_decode_audio*.
It would be sufficient to have an approximate representation where only every x-th audio frame is decoded. I tried to "jump" to the next position using "av_seek_frame" but this slows down the whole process even more.
Are there means to sample a decoded audio file only every x-th position? Or are there other (better) means to get the data for the graph?

Regards,