Appraisal of H.264 Codec

H.264/AVC, the latest video Codec standard is the most popular among Video professionals owing to its exact and unambiguous guidelines for dealing with the input stream to be transported from one place to another, having minimum loss in the transit and a very good compression ratio, both attributes highly sought after in today’s world of high quality multimedia broadcast and reception. Another parameter is the bit rate with which the data has to be transmitted. This paper is an attempt to show how various input parameters affect the output of the H.264 Codec. The input video file is a .yuv file, which after encoding becomes a .264 file, which is also called a stream file because this file has to be sent as a stream to various locations owing to its small size. At the receiving end, this stream file is decoded back into .yuv file. In the entire process, there is some loss in the quality of the video transmitted. This loss has to be minimum and is indicated by a parameter called PSNR (Peak Signal to Noise Ratio). Apart from PSNR, there are some other parameters as well like sequence parameter set, picture parameter set, information about different frames as regards slices and macroblocks, all ensconced in different files. PSNR being an important parameter will be dealt with here. There are three different input profiles namely, baseline profile, main profile and extended profile for H.264. In this work, variation of bit rate versus PSNR is studied in all the three profiles. A higher PSNR for a given constant bit rate is rated as a better performance. Here, the input sequence is a yuv file (foreman_part_qcif.yuv) with one reference frame. The quantization parameter for the I, B and P slices has been set at 30. The PSNR is plotted against bit rate and it is observed that they show a striking similarity with each other.