High energy coefficients in 1d DCT for audio

1. What is the DCT coefficient?
2. What is DCT how DCT helps to achieve compression?
3. Why is DCT preferred over DFT?
4. What is the purpose of discrete cosine transform?

What is the DCT coefficient?

DCT coefficient (0,0) is the DC coefficient, or average sample value. Since natural images tend to vary only slightly from sample to sample, low frequency coefficients are typically larger values and high frequency coefficients are typically smaller values. The 8×8 DCT is defined in Figure 5.21.

What is DCT how DCT helps to achieve compression?

DCT is used in the JPEG image compression algorithm. The input image is divided into 8-by-8 or 16-by-16 blocks, and the two-dimensional DCT is computed for each block. The DCT coefficients are then quantized, coded, and transmitted.

Why is DCT preferred over DFT?

> DCT is preferred over DFT in image compression algorithms like JPEG > because DCT is a real transform which results in a single real number per > data point. In contrast, a DFT results in a complex number (real and > imaginary parts) which requires double the memory for storage.

What is the purpose of discrete cosine transform?

Definition:Discrete Cosine Transform is a technique applied to image pixels in spatial domain in order to transform them into a frequency domain in which redundancy can be identified.