A codec includes an encoder having a quantization level generator that defines a quantization level specific to a block of values (e.g., transform coefficients), a quantizer that quantizes the block of transform coefficients according to the block-specific quantization level, a run-length encoder, and an entropy encoder. The quantization level is defined to result in at least a predetermined number (k) of quantized coefficients having a predetermined value. The amount of data compression by the encoder is proportional to (k). The codec also includes a decoder having entropy and run-length decoding sections whose throughputs are proportional to (k). The decoder takes advantage of this increased throughput by further decoding coefficients in parallel using a plurality of decoding channels. Methods for encoding and decoding data are also disclosed. The invention is well-suited to quantization, entropy, and/or run-length-based codecs, such as JPEG.