The Truth About High Bitrate Lossy Compression Part 2
I decided to “drop” the three specified formats to get the highest quality sound with the minimum file size.
For the test, we selected several samples (here a sample is a small fragment cut from a PCM file) from two types of compositions. The first is a very dense and loud sound with amplitude normalization (compacting the sound “vertically” to fit 16-bit from a 24-bit master) and compression of the dynamic range (so that the sound of all instruments is always strong). As the first type (as in my previous tests), the composition Crush On You from the album Have A Nice Day by Roxette was chosen, three samples of 15-20 seconds each of different parts of the composition were examined. The second sample is clean and transparent (acoustic or light orchestral arrangement).
Why these particular records? Roxette samples have very strong dynamic compression (the amplitude value is very often equal to the maximum (which is bad) and leads to overload of the playback equipment and strong distortions).
Roxette sample
In such samples, the encoders have to work in extreme mode, so any distortion becomes easily audible. encoding distortions add to the existing intrinsic distortions of the original. You ask “why then take a sample as a test?” It is necessary and how. The vast majority of albums released today are recorded this way. Therefore, the encoder must adequately accept clipping sound.
With Klaiderman’s samples, the situation is diametrically opposite. The original analog recording after a very high quality digital remastering was recorded to CD and without dynamic compression.
Clayderman sample
Great sound, very nice and smooth highs. We will pay special attention to them during the analysis, we will try to preserve them. But it is these frequencies that will be the most difficult for encoders to transmit.
