Efficient MPEG-2 to MPEG-4 video transcoding

Shan Liu; Ligang Lu; C.-C. Jay Kuo

doi:10.1117/12.476712

7 May 2003 Efficient MPEG-2 to MPEG-4 video transcoding

Shan Liu, Ligang Lu, C.-C. Jay Kuo

Proceedings Volume 5022, Image and Video Communications and Processing 2003; (2003) https://doi.org/10.1117/12.476712
Event: Electronic Imaging 2003, 2003, Santa Clara, CA, United States

Abstract

An efficient MPEG-2 to MPEG-4 video transcoder is presented in this paper. We consider the transcoding from high quality and bit rate MPEG-2 video with larger image size (e.g. 4CIF/4SIF, CIF) to lower quality and bit rate MPEG-4 video with smaller image size (e.g. CIF, QCIF). First, the transcoder needs to down-sample the input MPEG-2 video. Since the motion vectors carried by the MPEG-2 stream will be reused in the transcoding process, they are sub-sampled besides the frame pixels, and the coding mode for each down-sampled macroblock is examined. A new rate control method is proposed to convert the high bit rate MPEG-2 video to the low bit rate MPEG-4 counterpart. The proposed rate control scheme adjusts the frame rate and the frame quantization step size simultaneously according to the channel bandwidth to achieve a good temporal-spatial quality tradeoff. Due to the reuse of motion vectors, key frames (i.e. I and P frames) cannot be skipped to maintain the prediction sequential order, while some B frames containing less temporal information may be skipped in transcoding to save the bit rate. Skipped B frames can be reconstructed at the decoder to ensure the full frame rate playback. The TM7 quadratic Rate-Qtz model is adopted in the proposed rate control scheme to calculate the re-quantization step size from the given target bit. Simulations show that the proposed MPEG-2 to MPEG-4 video transcoder with rate control can out-perform the basic MPEG transcoder that adjusts the re-quantization step size at a constant frame rate. The complexity of the proposed transcoder is low so that it can be used in real-time applications.

Citation Download Citation

Shan Liu, Ligang Lu, and C.-C. Jay Kuo "Efficient MPEG-2 to MPEG-4 video transcoding", Proc. SPIE 5022, Image and Video Communications and Processing 2003, (7 May 2003); https://doi.org/10.1117/12.476712

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available