台灣數位學習數位教學平台 RSS feed provider zh-tw http://sites.xms.com.tw/board.php?courseID=135&f=doclist&folderID= http://sites.xms.com.tw/board.php?courseID=135&f=doc&cid=2924 每張frame都可以參考（包含B slices) 兩個往前以及往後的動態向量(list0, list1) 可用權重分配產生最後的動態向量 四種權重模式 [llist0], [list1], [bi-predictive], [direct prediction]或 B_Skip 每一個partition可用不同的模式. Tue, 28 Sep 2010 19:23:35 +0800 http://sites.xms.com.tw/board.php?courseID=135&f=doc&cid=2923 針對之編碼模式: INTRA 4X4, INTRA 16X16, INTER 16X16, INTER 16X8, INTER 8X16, INTER 8X8, INTER 8X4, INTER 4X8, INTER 4X4, SKIP and DIRECT. 利用拉格蘭日乘數法達到最佳位元分配 Tue, 28 Sep 2010 19:23:08 +0800 http://sites.xms.com.tw/board.php?courseID=135&f=doc&cid=2922 避免編碼時區塊化的效應 在編碼流程中加入去區塊化濾波器 有別於編碼後再加入的濾波動作 可以達到更有效率的編碼 Tue, 28 Sep 2010 19:22:29 +0800 http://sites.xms.com.tw/board.php?courseID=135&f=doc&cid=2920 利用所謂 quantization parameter (QP)值來達到純量量化的效果 共有52種QP值QP值每增加1會增加約 12％的位元率故約增加6個QP會達到兩倍QSTEP= 2(QP-4)/6QSTEP就代表位元率的增長 Tue, 28 Sep 2010 19:21:19 +0800 http://sites.xms.com.tw/board.php?courseID=135&f=doc&cid=2919   Tue, 28 Sep 2010 19:17:24 +0800 http://sites.xms.com.tw/board.php?courseID=135&f=doc&cid=2750 流程圖並未列出所有x264 Codec上的函式, 僅列出具有影音說明檔的函式. 函式名稱用紅色邊框 圍住, 表示此函式底下仍有子函式, 點下函式名稱可以連結到子函式的流程圖. 點選函式下方的圖形, 將會連結到此函式的影音說明網頁. 流程圖右方的欄位列出x264 Codec中所有擁有影音說明檔案的函式, 點下函式名稱會連結到此函式的影音說明網頁. 我們建議瀏覽此流程圖使用, 否則部分功能將無法顯示出來. 按下這裡開始 Wed, 15 Sep 2010 11:01:38 +0800 http://sites.xms.com.tw/board.php?courseID=135&f=doc&cid=2749 The flow chart does not include all the functions in x264 Codec. The functions withred edge in the flow chart represent other sub-functions will be called inside these functions. The web page will be redirected to the corresponding sub-flow chart by clicking these functions. Click thebelow each function, and the web page will be directed to the corresponding sound recording page. The right column lists all the functions in x264 with sound recording page. Click the function name, the web page will be directed to the corresponding sound recording page. We suggest to visit the page with , or some functionality will not work properly. Click here to start Wed, 15 Sep 2010 11:01:19 +0800 http://sites.xms.com.tw/board.php?courseID=135&f=doc&cid=2748 流程圖上的部分函式可以點選, 表示此函式底下仍有子函式, 點下函式名稱可以連結到子函式的流程圖. 如果此函式有影音說明檔, 則影音說明連結會被列在函式流程圖的下方, 點下去可以連結到該函式的影音說明頁面. 我們建議瀏覽此流程圖使用, 否則部分功能將無法顯示出來. 按下這裡開始 Wed, 15 Sep 2010 11:00:46 +0800 http://sites.xms.com.tw/board.php?courseID=135&f=doc&cid=2747 Some functions in the flow chart can be clicked represent that other sub-functions will be called inside these functions. If the function has sound recording, the sound recording link will be listed below flow chart. Click the link, the web page will be directed to the corresponding sound recording page. We suggest to visit the page with , or some functionality will not work properly. Click here to start Wed, 15 Sep 2010 11:00:16 +0800 http://sites.xms.com.tw/board.php?courseID=135&f=doc&cid=2746 適合用於平緩變化的區域，有四種模式 prediction modes Vertical prediction, Horizontal prediction , DC-prediction , and Plane-prediction 對於Chrominance signals部分 因為大多相當平滑 直接對8X 8採用 Intra_16X16 Wed, 15 Sep 2010 10:55:21 +0800 http://sites.xms.com.tw/board.php?courseID=135&f=doc&cid=2745 有9種預測模式可以選擇   Wed, 15 Sep 2010 10:54:19 +0800 http://sites.xms.com.tw/board.php?courseID=135&f=doc&cid=2743 針對非零個數，以及其值和位置獨立作編碼 Example:7, 6, -2, 0, -1, 0, 0, 1, 0, 0, 0, 0, 0, 0 ,0 ,0. 第一步 # of nonzero coefficients (N) and "Trailing T1s"計算非零值和所謂的 "Trailing T1s"T1s = 2, N = 5,這兩個數字以組合的事件壓縮，從四個VLC表中，根據相鄰區塊的係數找一個使用 第二步 Encoding the value of Coefficients對非零係數作編碼， T1s只需記錄正負號非零係數以反序記錄 -2, 6, …並利用不同的VLC表達到適應式編碼六個 exp-Golomb code 表可供使用 第三步 Sign Information傳送正負號T1s 使用一個位元表示其餘係數之正負號則包含在 exp-Golomb codes 之中 第四步 TotalZeroes傳送從最後一個非零數值到開始之間的的零值個數TotalZeroes = 3N=5意味著所有非零值介於 0-11,有15個表可供選擇來編碼N=16 表示沒有非零值 第五步 RunBefore記錄上一步的零值的位置 Wed, 15 Sep 2010 10:52:19 +0800 http://sites.xms.com.tw/board.php?courseID=135&f=doc&cid=2742 Wed, 15 Sep 2010 10:51:37 +0800 http://sites.xms.com.tw/board.php?courseID=135&f=doc&cid=2740 採用七種不同的macro block大小來做運動向量的估   Wed, 15 Sep 2010 10:43:23 +0800 http://sites.xms.com.tw/board.php?courseID=135&f=doc&cid=2739 可參考前後5張FRAME Wed, 15 Sep 2010 10:42:24 +0800 http://sites.xms.com.tw/board.php?courseID=135&f=doc&cid=2738 利用內插法達到1/2，1/4的精準度動作向量估計 Wed, 15 Sep 2010 10:41:07 +0800 http://sites.xms.com.tw/board.php?courseID=135&f=doc&cid=2737 Wed, 15 Sep 2010 10:38:17 +0800 http://sites.xms.com.tw/board.php?courseID=135&f=doc&cid=2736 x264 is a free software library and application for encoding video streams into the H.264/MPEG-4 AVC format, and is released under the terms of the GNU GPL. The code is written from scratch by Laurent Aimar, Loren Merritt, Eric Petit (OS X), Min Chen (vfw/asm), Justin Clay (vfw), Mans Rullgard, Radek Czyz, Christian Heine (asm), Alex Izvorski, Alex Wright and Jason Garrett-Glaser. It provides best-in-class performance, compression, and features. Performance-wise, x264 can encode 4 or more 1080p streams in realtime on a single consumer-level computer. Quality-wise, x264 has the world's most advanced psychovisual optimizations and has won many awards, . Feature-wise, x264 supports features necessary for many different applications, such as television broadcast, Blu-ray, low-latency video applications, and web video. x264 forms the core of many web video services, such as Youtube, Facebook, Vimeo, and Hulu. It is also used in television broadcast by companies such as Avail Media. Refrenced from http://www.videolan.org/developers/x264.html Online Source Code Download Source Code Wed, 15 Sep 2010 10:26:08 +0800 http://sites.xms.com.tw/board.php?courseID=135&f=doc&cid=2735 This is the H.264/AVC encoder reference software. For detailed documentation see the comments in each file. Online Source Code(JM) Download Source Code(JM) Download the JM reference software manual (JVT-AE010) [PDF] H.264 Recommendation Wed, 15 Sep 2010 10:25:40 +0800 http://sites.xms.com.tw/board.php?courseID=135&f=doc&cid=2734 H.264/MPEG-4 Part 10 or AVC (Advanced Video Coding) is a standard for video compression. The final drafting work on the first version of the standard was completed in May 2003. H.264/MPEG-4 AVC is a block-oriented motion-compensation-based codec standard developed by the ITU-T Video Coding Experts Group (VCEG) together with the ISO/IEC Moving Picture Experts Group (MPEG). It was the product of a partnership effort known as the Joint Video Team (JVT). The ITU-T H.264 standard and the ISO/IEC MPEG-4 AVC standard (formally, ISO/IEC 14496-10 - MPEG-4 Part 10, Advanced Video Coding) are jointly maintained so that they have identical technical content. H.264 is used in such applications as Blu-ray Disc, videos from YouTube and the iTunes Store, DVB broadcast, direct-broadcast satellite television service, cable television services, and real-time videoconferencing. Refrenced from http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC Wed, 15 Sep 2010 10:23:51 +0800