<div dir="ltr"><span style="background-color:rgb(255,255,255)"><span class="" id="Sp1.s2_o" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"><span class="" value="0404/verb:plain" id="token_1">Thank</span> <span class="" value="7878/pron" id="token_2">you</span> <span class="" value="5050/prep" id="token_3">for</span> <span class="" value="2828/det" id="token_4">this</span> <span class="" value="2020/adj:base" id="token_5">quick</span> <span class="" value="1010/noun:common" id="token_6">response</span><span class="" id="token_7">,</span></span><br style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">
<br><span class="" id="Sp2.s2_o" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"><span class="" value="7070/pron" id="token_1">I</span> <span class="" value="080b/verb:plain" id="token_2">don't</span> <span class="" value="0448/verb:plain" id="token_4">indicate</span> <span class="" value="3c3d/det" id="token_5">the</span> <span class="" value="1010/noun:common" id="token_6">number</span> <span class="" value="5050/prep" id="token_7">of</span> <span class="" value="1010/noun:common" id="token_8">thread</span><span class="" id="token_9">,</span> <span class="" value="6868/conj" id="token_10">but</span> <span class="" value="7070/pron" id="token_11">I</span> <span class="" value="0404/verb:plain" id="token_12">checked</span> <span class="" value="3c3d/det" id="token_13">the</span> <span class="" value="1010/noun:common" id="token_14">value</span> <span class="" value="5050/prep" id="token_15">of</span> <span class="" value="3c3d/det" id="token_16">the</span> <span class="" value="1010/noun:common" id="token_17">parameter</span> <span class="" id="token_18">"</span><span class="" value="1010/noun:common" id="token_19">i_thread_frames</span><span class="" id="token_20">"</span><span class="" id="token_21">,</span> <span class="" value="7878/pron" id="token_22">it</span> <span class="" value="4004/verb:plain" id="token_23">is</span> <span class="" value="3030/adv" id="token_24">automatically</span> <span class="" value="0438/verb:plain" id="token_25">set</span> <span class="" value="5050/prep" id="token_26">to</span> <span class="" id="token_27">24</span><span class="" id="token_28">.</span></span><br style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">
<br><span class="" id="Sp3.s2_o" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"><span class="" value="3030/adv" id="token_1">So</span> <span class="" value="7070/pron" id="token_2">I</span> <span class="" value="0404/verb:plain" id="token_3">made</span> <span class="" value="a015/numeric" id="token_4">two</span> <span class="" value="1010/noun:common" id="token_5">tests</span> <span class="" id="token_6">(</span><span class="" value="1013/noun:acronym" id="token_7">x264</span></span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" id="token_8" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">--</span><span class="" id="Sp3.s4_o" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"><span class="" value="1013/noun:acronym" id="token_9">input-res</span> <span class="" value="1013/noun:acronym" id="token_10">1920x1080</span></span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" id="token_11" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">--</span><span class="" id="Sp3.s6_o" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"><span class="" value="1010/noun:common" id="token_12">fps</span> <span class="" id="token_13">25</span></span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" id="token_14" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">--</span><span class="" id="Sp3.s8_o" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"><span class="" value="1010/noun:common" id="token_15">bitrate</span> <span class="" id="token_16">8000</span></span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" id="token_17" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">--</span><span class="" id="Sp3.s10_o" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"><span class="" value="1010/noun:common" id="token_18">vbv-maxrate</span> <span class="" id="token_19">8000</span> <span class="" id="token_20">...</span><span class="" id="token_21">)</span></span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" id="token_22" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">:</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span></span><div>
<span class="" value="a01e/numeric" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px;background-color:rgb(255,255,255)"><br></span></div>
<div><span style="background-color:rgb(255,255,255)"><span class="" value="a01e/numeric" id="token_23" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">1</span><span class="" id="token_24" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">.</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" id="Sp3.s13_o" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"><span class="" value="7070/pron" id="token_25">I</span> <span class="" value="0404/verb:plain" id="token_26">increase</span> <span class="" value="3c3d/det" id="token_27">the</span> <span class="" value="1010/noun:common" id="token_28">buffer</span> <span class="" value="1010/noun:common" id="token_29">size</span> <span class="" id="token_30">(</span><span class="" value="3030/adv" id="token_31">initially</span> <span class="" value="1013/noun:acronym" id="token_32">3M=9~10frames</span><span class="" id="token_33">)</span> <span class="" value="5050/prep" id="token_34">to</span> <span class="" value="a01d/numeric" id="token_35">8M</span> <span class="" id="token_36">(</span><span class="" id="token_37">25</span> <span class="" value="1010/noun:common" id="token_38">frames</span><span class="" id="token_39">)</span></span></span></div>
<div><span style="background-color:rgb(255,255,255)"><span class="" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"><span class="" value="0404/verb:plain" id="token_40">vbv_bufsize</span> <span class="" id="token_41">=</span> </span><span class="" style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif"><span class="" value="1011/noun:propernoun" id="token_42">3M</span></span><span style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif"> </span><span class="" id="token_43" style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif">--</span><span class="" id="Sp3.s15_o" style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif"><span class="" id="token_44">></span> <span class="" value="3838/verb:pastpart" id="token_45">achieved</span> <span class="" value="1010/noun:common" id="token_46">bitrate</span> <span class="" id="token_47">=</span>  <span class="" value="1013/noun:acronym" id="token_48">6125.30</span></span></span></div>
<div><span style="background-color:rgb(255,255,255)"><span class="" style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif"><span class="" value="1013/noun:acronym">vbv_bufsize</span> <span class="" id="token_49">=</span> <span class="" value="a01d/numeric" id="token_50">8M</span></span><span style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif"> </span><span class="" id="token_51" style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif">--</span><span class="" id="Sp3.s17_o" style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif"><span class="" id="token_52">></span> <span class="" value="3838/verb:pastpart" id="token_53">achieved</span> <span class="" value="1010/noun:common" id="token_54">bitrate</span> <span class="" id="token_55">=</span>  <span class="" id="token_56">6904.92</span><span class="" id="token_57">.</span></span><span style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif"> </span></span></div>
<div><span class="" style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif"><span class="" value="7070/pron" style="background-color:rgb(255,255,255)"><br>
</span></span></div><div><span style="background-color:rgb(255,255,255)"><span class="" id="Sp3.s18_o" style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif"><span class="" value="7070/pron" id="token_58">2. I</span> <span class="" value="0404/verb:plain" id="token_59">decrease</span> <span class="" value="3c3d/det" id="token_60">the</span> <span class="" value="1010/noun:common" id="token_61">number</span> <span class="" value="5050/prep" id="token_62">of</span> <span class="" value="1010/noun:common" id="token_63">thread</span> <span class="" id="token_64">(</span><span class="" value="3030/adv" id="token_65">initially</span> <span class="" id="token_66">24</span><span class="" id="token_67">)</span> <span class="" value="5050/prep" id="token_68">to</span> <span class="" id="token_69">8</span><span class="" id="token_70">,</span> <span class="" value="5050/prep" id="token_71">with</span> <span class="" value="0404/verb:plain" id="token_72">bufsize</span> <span class="" value="1011/noun:propernoun" id="token_73">3M</span> <span class="" id="token_74">:</span></span><span style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif"> </span></span></div>
<div><span style="background-color:rgb(255,255,255)"><span class="" id="Sp3.s19_o" style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif"><span class="" value="1010/noun:common" id="token_75">i_thread_frames</span> <span class="" id="token_76">=</span> <span class="" id="token_77">24</span></span><span style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif"> </span><span class="" id="token_78" style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif">--</span><span class="" id="Sp3.s21_o" style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif"><span class="" id="token_79">></span> <span class="" value="3838/verb:pastpart" id="token_80">achieved</span> <span class="" value="1010/noun:common" id="token_81">bitrate</span> <span class="" id="token_82">=</span>  <span class="" id="token_83">6125.30</span><span class="" id="token_84">,</span> <span class="" value="1010/noun:common" id="token_85">fps</span> <span class="" id="token_86">=</span> <span class="" value="1013/noun:acronym" id="token_87">22.04</span></span></span></div>
<div><span style="background-color:rgb(255,255,255)"><span class="" style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif"><span class="" value="1013/noun:acronym">i_thread_frames</span> <span class="" id="token_88">=</span> <span class="" id="token_89">8</span></span><span style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif"> </span><span class="" id="token_90" style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif">--</span><span class="" id="Sp3.s23_o" style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif"><span class="" id="token_91">></span> <span class="" value="3838/verb:pastpart" id="token_92">achieved</span> <span class="" value="1010/noun:common" id="token_93">bitrate</span> <span class="" id="token_94">=</span>  <span class="" id="token_95">7166.56</span><span class="" id="token_96">,</span> <span class="" value="1010/noun:common" id="token_97">fps</span> <span class="" id="token_98">=</span> <span class="" id="token_99">10.99</span></span></span></div>
<div><span style="background-color:rgb(255,255,255)"><span class="" id="token_100" style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif">--</span><span class="" id="Sp3.s25_o" style="font-size:13px;color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif"><span class="" id="token_101">></span> <span class="" value="3030/adv" id="token_102">Actually</span><span class="" id="token_103">,</span> <span class="" value="5c5c/conj" id="token_104">if</span> <span class="" value="7070/pron" id="token_105">I</span> <span class="" value="0404/verb:plain" id="token_106">decrease</span> <span class="" value="3c3d/det" id="token_107">the</span> <span class="" value="1010/noun:common" id="token_108">number</span> <span class="" value="5050/prep" id="token_109">of</span> <span class="" value="1010/noun:common" id="token_110">threads</span><span class="" id="token_111">,</span> <span class="" value="3c3d/det" id="token_112">the</span> <span class="" value="3838/verb:pastpart" id="token_113">achieved</span> <span class="" value="1010/noun:common" id="token_114">bitrate</span> <span class="" value="4004/verb:plain" id="token_115">is</span> <span class="" value="2021/adj:comparative" id="token_116">better</span> <span class="" value="6868/conj" id="token_117">but</span> <span class="" value="3434/adv" id="token_118">of course</span><span class="" id="token_119">,</span> <span class="" value="3c3d/det" id="token_120">the</span> <span class="" value="1010/noun:common" id="token_121">number</span> <span class="" value="5050/prep" id="token_122">of</span> <span class="" value="1010/noun:common" id="token_123">frames</span> <span class="" value="3838/verb:pastpart" id="token_124">coded</span> <span class="" value="5050/prep" id="token_125">per</span> <span class="" value="1010/noun:common" id="token_126">second</span><span class="" id="token_127">,</span> <span class="" value="1010/noun:common" id="token_128">decreases</span> <span class="" value="6465/conj" id="token_129">and</span> <span class="" value="2428/pron" id="token_130">that</span> <span class="" value="4004/verb:plain" id="token_131">is</span> <span class="" value="3031/adv" id="token_132">not</span> <span class="" value="3c3e/det" id="token_133">a</span> <span class="" value="1010/noun:common" id="token_134">solution</span> <span class="" value="5050/prep" id="token_135">for</span> <span class="" value="3c3e/det" id="token_136">a</span> <span class="" value="2020/adj:base" id="token_137">real time</span> <span class="" value="1010/noun:common" id="token_138">application</span><span class="" id="token_139">.</span></span><br>
</span></div><div><span class="" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"><span class="" value="2428/pron" style="background-color:rgb(255,255,255)"><br>
</span></span></div><div><span style="background-color:rgb(255,255,255)"><span class="" id="Sp4.s2_o" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"><span class="" value="2428/pron" id="token_1">That</span> <span class="" value="4004/verb:plain" id="token_2">is</span> <span class="" value="3030/adv" id="token_3">very</span> <span class="" value="2025/adj:ppresent" id="token_4">suprising</span> <span class="" value="5050/prep" id="token_5">for</span> <span class="" value="7474/pron" id="token_6">me</span><span class="" id="token_7">,</span> <span class="" value="4004/verb:plain" id="token_8">is</span> <span class="" value="5c5d/conj" id="token_9">that</span> <span class="" value="3c3d/det" id="token_10">the</span> <span class="" value="1010/noun:common" id="token_11">rate</span> <span class="" value="1010/noun:common" id="token_12">control</span> <span class="" value="0404/verb:plain" id="token_13">allocates</span> <span class="" value="3030/adv" id="token_14">very</span> <span class="" value="2829/det" id="token_15">few</span> <span class="" value="1010/noun:common" id="token_16">bits</span> <span class="" value="5050/prep" id="token_17">to</span> <span class="" value="3c3d/det" id="token_18">the</span> <span class="" value="2c2e/numeric" id="token_19">first</span> <span class="" value="1010/noun:common" id="token_20">frames</span><span class="" id="token_21">,</span> <span class="" value="6465/conj" id="token_22">and</span> <span class="" value="7878/pron" id="token_23">it</span> <span class="" value="0404/verb:plain" id="token_24">spends</span> <span class="" value="2829/det" id="token_25">all</span> <span class="" value="3c3d/det" id="token_26">the</span> <span class="" value="1010/noun:common" id="token_27">sequence</span> <span class="" id="token_28">(</span><span class="" id="token_29">200</span> <span class="" value="1010/noun:common" id="token_30">frames</span><span class="" id="token_31">)</span> <span class="" value="a8a8/part" id="token_32">to</span> <span class="" value="4848/verb:inf" id="token_33">increase</span> <span class="" value="3c3d/det" id="token_34">the</span> <span class="" value="1010/noun:common" id="token_35">number</span> <span class="" value="5050/prep" id="token_36">of</span> <span class="" value="1010/noun:common" id="token_37">bit</span> <span class="" value="5050/prep" id="token_38">per</span> <span class="" value="1010/noun:common" id="token_39">frame</span> <span class="" value="a8a8/part" id="token_40">to</span> <span class="" value="4848/verb:inf" id="token_41">reach</span> <span class="" value="3c3d/det" id="token_42">the</span> <span class="" value="1010/noun:common" id="token_43">target</span> <span class="" value="1010/noun:common" id="token_44">bitrate</span><span class="" id="token_45">.</span></span><br>
<span class="" id="Sp5.s2_o" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"><span class="" value="5c5c/conj" id="token_1">If</span> <span class="" value="3c3d/det" id="token_2">the</span> <span class="" value="1010/noun:common" id="token_3">target</span> <span class="" value="1010/noun:common" id="token_4">bitrate</span> <span class="" value="4004/verb:plain" id="token_5">is</span> <span class="" value="0438/verb:plain" id="token_6">specified</span><span class="" id="token_7">,</span> <span class="" value="3033/adv" id="token_8">why</span> <span class="" value="3c3d/det" id="token_9">the</span> <span class="" value="1010/noun:common" id="token_10">rate</span> <span class="" value="1010/noun:common" id="token_11">control</span> <span class="" value="0404/verb:plain" id="token_12">allocates</span> <span class="" value="2829/det" id="token_13">too few</span> <span class="" value="1010/noun:common" id="token_14">bit</span> <span class="" value="5050/prep" id="token_15">at the begining of</span> <span class="" value="3c3d/det" id="token_16">the</span> <span class="" value="1010/noun:common" id="token_17">sequence</span><span class="" id="token_18">?</span></span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" id="Sp5.s3_o" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"><span class="" value="7070/pron" id="token_19">I</span> <span class="" value="0404/verb:plain" id="token_20">checked</span> <span class="" value="3c3d/det" id="token_21">the</span> <span class="" value="1010/noun:common" id="token_22">value</span> <span class="" value="5050/prep" id="token_23">of</span> <span class="" value="3c3d/det" id="token_24">the</span> <span class="" value="1010/noun:common" id="token_25">parameter</span> <span class="" id="token_26">"</span><span class="" value="1010/noun:common" id="token_27">wanted_bits_window</span><span class="" id="token_28">"</span> <span class="" value="6465/conj" id="token_29">and</span> <span class="" value="7878/pron" id="token_30">it</span> <span class="" value="4004/verb:plain" id="token_31">is</span> <span class="" value="1010/noun:common" id="token_32">bitrate</span><span class="" id="token_33">/</span><span class="" value="1010/noun:common" id="token_34">fps</span> <span class="" value="6c6c/conj" id="token_35">as</span> <span class="" value="3838/verb:pastpart" id="token_36">expected.</span></span></span><div style>
<span style="background-color:rgb(255,255,255)"><br></span></div><div style><span style="background-color:rgb(255,255,255)">The only solution I found is to use VBR (ABR) : <span style="font-size:13px;color:rgb(80,0,80);font-family:arial,sans-serif">x264 --input-res 1920x1080 --fps 25 --bitrate 8000 --vbv-maxrate 24000 </span>vbv_bufsize 3000</span></div>
</div><div style><span style="background-color:rgb(255,255,255)"><span class="" value="3030/adv" id="token_1" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">In t</span><span class="" value="3030/adv" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">his case</span><span class="" id="token_2" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">,</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="3c3d/det" id="token_3" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">the</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="1010/noun:common" id="token_4" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">rate</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="1010/noun:common" id="token_5" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">control</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="0404/verb:plain" id="token_6" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">allocates</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="3c3d/det" id="token_7" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">the</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="2020/adj:base" id="token_8" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">good</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="1010/noun:common" id="token_9" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">number</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="5050/prep" id="token_10" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">of</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="1010/noun:common" id="token_11" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">bits</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="5050/prep" id="token_12" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">per</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="1010/noun:common" id="token_13" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">frame</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="5c5c/conj" id="token_14" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">right from the</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> start of the sequence</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="6465/conj" id="token_18" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">and</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="7878/pron" id="token_19" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">it</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="0404/verb:plain" id="token_20" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">succeeds</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="5050/prep" id="token_21" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">in</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="4c4c/verb:prespart" id="token_22" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">achieving</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="3c3d/det" id="token_23" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">the</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="1010/noun:common" id="token_24" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">target</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="1010/noun:common" id="token_25" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">bitrate</span><span class="" id="token_26" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">,</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="6868/conj" id="token_27" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">but</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="7070/pron" id="token_28" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">I</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="0808/verb:plain" id="token_29" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">cannot</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="4448/verb:inf" id="token_31" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">be</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="2020/adj:base" id="token_32" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">sure</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="5c5d/conj" id="token_33" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">that</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px"> </span><span class="" value="3c3d/det" id="token_34" style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','arial unicode ms',code2000,verdana,sans-serif;font-size:13px">the</span><span style="color:rgb(0,0,0);font-family:arial,helvetica,'lucida sans','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</span></div><div style><br></div></div><div class="gmail_extra"><br><br><div class="gmail_quote">2013/1/29 Jason Garrett-Glaser <span dir="ltr"><<a href="mailto:jason@x264.com" target="_blank">jason@x264.com</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">On Tue, Jan 29, 2013 at 7:35 AM, eloise vidal <<a href="mailto:eloise.vidal@gmail.com">eloise.vidal@gmail.com</a>> wrote:<br>

> I am working on CBR streaming applications and I compare x264 to Mainconcept<br>
> in terme of quality (PSNR, SSIM), performance (frame encoded per second) and<br>
> rate control accuracy.<br>
><br>
> I read the "Video Codec Comparison" of CS MSU Graphics&Media Lab, Video<br>
> Group. This comparison shows that x264 is the best codec in terme of SSIM,<br>
> but I cannot find the same results because of the rate control.<br>
><br>
> I use sequences of 200 frames for my tests. Here is an exemple of the<br>
> command line I use for HD sequence :<br>
> x264 --input-res 1920x1080 --fps 25 --bitrate 8000 --vbv-maxrate 8000<br>
> --vbv-bufsize 3000 --profile high -o Output.h264 Input.yuv<br>
><br>
> Mainconcept uses a buffer size of 3Mbit for HD sequence<br>
<br>
</div>Erm, the encoder doesn't use a specific buffer size; you set the<br>
buffer size based on your use-case.<br>
<div class="im"><br>
> With this buffer size, x264 does not succeed in achieving 8Mb/s but 6MB/s.<br>
> To achieve 8Mb/s, I have to choose a bigger buffer of 35Mbit, but firstly I<br>
> add more than 4sec of latency!<br>
<br>
</div>On a very short clip, you may get well over or under the target<br>
bitrate because the buffer state at the end of the video may be<br>
different than the buffer state at the start.<br>
<br>
Additionally, that small of a VBV buffer doesn't match any real-world<br>
application that I know of.  Even broadcast is usually about 0.7-1<br>
second at the least.<br>
<div class="im"><br>
> And secondly, the rate control needs a lot of<br>
> frames to be stable, a small number of bits are allocated to the frames at<br>
> the begining of the sequence<br>
<br>
</div>How many threads are you using?  If you're using significantly more<br>
threads than the VBV buffer fits frames, x264's compression will<br>
suffer dramatically.<br>
<br>
Jason<br>
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</blockquote></div><br></div>