When using the transcoder , if a mobile user clicks on the streaming url , it will automatically send a rtsp request to the 3gpp streaming server , which then decodes the url and inform the real - time video transcoder to begin requesting for the original streaming media from the internet media server for transcoding and eventually streaming to the mobile handset 當(dāng)使用轉(zhuǎn)碼器時(shí),如果流動(dòng)用戶點(diǎn)擊一個(gè)視像網(wǎng)址,它便會(huì)自動(dòng)傳送rtsp往3gpp串流伺服器,然后將視像網(wǎng)址解碼,并通知即時(shí)視像轉(zhuǎn)碼器向互聯(lián)網(wǎng)媒體伺服器要求原有的串流媒體以作解碼,最終串流至流動(dòng)手機(jī)。
Note that we achieve this goal at expense of numerous computation and frequent memory i / o . actually , it is not feasible to put so much workload on scaling which is only a subsection of whole transcoder . through polyphase decomposition of fir filter , we can avoid a mass of redundant computation and decrease memory i / o 所以在基于軟件的實(shí)現(xiàn)時(shí),我們必須設(shè)計(jì)更加巧妙的濾波結(jié)構(gòu)從而減少不必要的運(yùn)算,通過對(duì)各種結(jié)構(gòu)的對(duì)比和試驗(yàn),發(fā)現(xiàn)基于fir的多相濾波器結(jié)構(gòu)能夠滿足我們的要求,通過對(duì)fir濾波器的分解,我們可以省去大量的不必要計(jì)算和內(nèi)存i o ,從而可以節(jié)約很多時(shí)間但保證圖像質(zhì)量毫無損失。
And according to this arbitrary size conversion , a motion - vector reusing algorithm is put forward too . because the motion vector reusing method can reduce the complexity to a great extend , while the video quality difference between this method and the new complete motion estimation method is small , the motion - vector reusing algorithm is widely adopted by many transcoders . in addition , compressed domain transcoder can skip the dct / idct transformation processes , so as to reduce the complexity greatly 另外,壓縮域轉(zhuǎn)碼,比空域轉(zhuǎn)碼節(jié)省了dct idct變換對(duì),可以降低運(yùn)算復(fù)雜性,因此文中又論述了壓縮域轉(zhuǎn)碼處理方法,包括dct域圖像下采樣(主要針對(duì)變換比例較簡(jiǎn)單的情況) 、 dct域反運(yùn)動(dòng)補(bǔ)償和dct域運(yùn)動(dòng)補(bǔ)償算法。