SSIM-based content adaptive frame skipping for low bit rate H.264 video coding

Conventional rate control schemes for H.264/AVC video coding usually regulate output bit rate to match channel bandwidth by adjusting quantization parameter at fixed full frame rate, and the passive frame skipping to avoid buffer overflow usually occurs when scene changes or high motions exist in video sequences especially at low bit rate, which degrades spatial-temporal quality and causes jerky effect. In this paper, an active content adaptive frame skipping scheme is proposed instead of passive methods, which skips subjectively trivial frames by structural similarity (SSIM) measurement. The saved bits from skipped frames are allocated to coded key ones to enhance their spatial quality, and the skipped frames are well recovered from adjacent key ones at the decoder side to maintain constant frame rate. Experimental results show that the proposed scheme acquires better and more consistent spatial-temporal quality both in objective (PSNR) and subjective (SSIM) sense with low complexity compared to classic fixed frame rate control methods JVT-G012.