• H.264级别（Level）计算器（JavaScript网页版）

    　　上回我们学会了怎么计算级别（H.264 级别（Level）、DPB 与 MaxDpbMbs 详解）。但是每次手工计算就太麻烦了，我们希望有一款工具能完成这些运算。最好该工具还能跨平台使用。

    　　在综合考虑上面的需求 和 开发难度性 后，我决定编写一个JavaScript网页程序。

    　　最终效果——

    　　其实开发难度并不大，只要熟悉上回的级别计算公式，就能很容易实现。全部代码如下——

    <!DOCTYPE html PUBLIC "-//W3C//Dtd XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/Dtd/xhtml1-transitional.dtd">
<html>
	<head>
		<title>H.264 Level Calculator</title>
		<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
		<script type="text/javascript">
// var
var tblLevels = [
	{Level:"1", MaxDpbMbs:396, MaxSecondMbs:1485, MaxFrameMbs:99}
	,{Level:"1b", MaxDpbMbs:396, MaxSecondMbs:1485, MaxFrameMbs:99}
	,{Level:"1.1", MaxDpbMbs:900, MaxSecondMbs:3000, MaxFrameMbs:396}
	,{Level:"1.2", MaxDpbMbs:2376, MaxSecondMbs:6000, MaxFrameMbs:396}
	,{Level:"1.3", MaxDpbMbs:2376, MaxSecondMbs:11880, MaxFrameMbs:396}
	,{Level:"2", MaxDpbMbs:2376, MaxSecondMbs:11880, MaxFrameMbs:396}
	,{Level:"2.1", MaxDpbMbs:4752, MaxSecondMbs:19800, MaxFrameMbs:792}
	,{Level:"2.2", MaxDpbMbs:8100, MaxSecondMbs:20250, MaxFrameMbs:1620}
	,{Level:"3", MaxDpbMbs:8100, MaxSecondMbs:40500, MaxFrameMbs:1620}
	,{Level:"3.1", MaxDpbMbs:18000, MaxSecondMbs:108000, MaxFrameMbs:3600}
	,{Level:"3.2", MaxDpbMbs:20480, MaxSecondMbs:216000, MaxFrameMbs:5120}
	,{Level:"4", MaxDpbMbs:32768, MaxSecondMbs:245760, MaxFrameMbs:8192}
	,{Level:"4.1", MaxDpbMbs:32768, MaxSecondMbs:245760, MaxFrameMbs:8192}
	,{Level:"4.2", MaxDpbMbs:34816, MaxSecondMbs:522240, MaxFrameMbs:8704}
	,{Level:"5", MaxDpbMbs:110400, MaxSecondMbs:589824, MaxFrameMbs:22080}
	,{Level:"5.1", MaxDpbMbs:184320, MaxSecondMbs:983040, MaxFrameMbs:36864}
];

// 取得命名对象
function getRef(id)
{
	if (document.getElementById) return document.getElementById(id);	// DOM
	if (document.all) return document.all[id];	// IE4
	if (document.layers) return document.layers[id];	// Netscape4
	return null;
}

// 取得控件文本。支持 input。
function getCtlText(ctl)
{
	if (null==ctl)	return;
	return ctl.value;
}

function input_onchange()
{
	// in
	var nwidth = Number(getCtlText(getRef("txtwidth")));
	var nheight = Number(getCtlText(getRef("txtheight")));
	var nfps = Number(getCtlText(getRef("txtfps")));
	var nref = Number(getCtlText(getRef("txtref")));
	var nlevel = getRef("txtLevel").selectedIndex;
	// out
	var txtolevel = getRef("txtolevel");
	var txtoframeMbs = getRef("txtoframeMbs");
	var txtosecondMbs = getRef("txtosecondMbs");
	var txtoDpbMbs = getRef("txtoDpbMbs");
	var txtofps = getRef("txtofps");
	var txtoref = getRef("txtoref");
	
	// debug
	//txtolevel.value = txtolevel.value + ".";
	//txtolevel.value = nwidth + ", " + nheight + ", " + nfps + ", "+ nref + ", " + nlevel;
	//txtolevel.value = tblLevels[nlevel % tblLevels.length].Level;
	
	// 计算level
	var frameMbs = Math.ceil(nwidth/16) * Math.ceil(nheight/16);	// 计算每帧宏块数
	var secondMbs = frameMbs * nfps;	// 计算每秒宏块数
	var DpbMbs = frameMbs * nref;	// 计算DPB宏块数
	var idx = NaN;	// 匹配的级别
	var bOK = false;	// 是否找到匹配的级别。
	var i;
	if (!isNaN(frameMbs))
	{
		// 查找第一个匹配的级别
		for(i=0; i<tblLevels.length; ++i)
		{
			// 判断每帧宏块数
			bOK = tblLevels[i].MaxFrameMbs >= frameMbs;
			// 判断每秒宏块数
			if (bOK && !isNaN(nfps) && nfps>0 )
			{
				bOK = tblLevels[i].MaxSecondMbs >= secondMbs;
			}
			// 判断DPB宏块数
			if (bOK && !isNaN(nref) && nref>0 )
			{
				bOK = tblLevels[i].MaxDpbMbs >= DpbMbs;
			}
			if (bOK)
			{
				idx = i;
				break
			}
		}
	}
	txtolevel.value = isNaN(idx)?NaN:tblLevels[idx].Level;
	txtoframeMbs.value = frameMbs;
	txtosecondMbs.value = secondMbs;
	txtoDpbMbs.value = DpbMbs;
	
	// 根据level约束计算fps/ref
	var ofps = NaN;	// 帧数
	var oref = NaN;	// 参考帧数
	if (!isNaN(nlevel) && nlevel>=0 && nlevel<tblLevels.length)
	{
		ofps = tblLevels[nlevel].MaxSecondMbs / frameMbs;
		oref = Math.min(16, tblLevels[nlevel].MaxDpbMbs / frameMbs);
	}
	txtofps.value = ofps;
	txtoref.value = oref;
}

function oninit()
{
	// 启动时计算一次
	input_onchange();
}

		</script>
	</head>
	<body onload='oninit()'>
		<h1>H.264 Level Calculator（H.264级别计算器）</h1>
		<p><span title='作者'>Author</span>: <a href='http://www.cnblogs.com/zyl910/'>zyl910</a></p>
		<form>
			<table id="tblview" border="1" cellSpacing="1" cellPadding="1">
				<tr>
					<th></th>
					<th>计算level</th>
					<th>根据level约束计算fps/ref</th>
				</tr>
				<tr>
					<th>in</th>
					<td>
						width（宽度）:<input id="txtwidth" value='1280' onchange='input_onchange()' /><br />
						height（高度）:<input id="txtheight" value='720' onchange='input_onchange()' /><br />
						fps（帧率）:<input id="txtfps" value='24' onchange='input_onchange()' /><br />
						ref（参考帧数）:<input id="txtref" value='3' onchange='input_onchange()' /><br />
					</td>
					<td>level（级别）:<select id="txtLevel" onchange='input_onchange()'>
							<option value='1'>1</option>
							<option value='1b'>1b</option>
							<option value='1.1'>1.1</option>
							<option value='1.2'>1.2</option>
							<option value='1.3'>1.3</option>
							<option value='2'>2</option>
							<option value='2.1'>2.1</option>
							<option value='2.2'>2.2</option>
							<option value='3'>3</option>
							<option value='3.1' selected>3.1</option>
							<option value='3.2'>3.2</option>
							<option value='4'>4</option>
							<option value='4.1'>4.1</option>
							<option value='4.2'>4.2</option>
							<option value='5'>5</option>
							<option value='5.1'>5.1</option>
						</select>
					</td>
				</tr>
				<tr>
					<th>out</th>
					<td>
						level（级别）:<input id="txtolevel" NAME="txtolevel" readonly /><br />
						frameMbs（每帧宏块）:<input id="txtoframeMbs" NAME="txtoframeMbs" readonly /><br />
						secondMbs（每秒宏块）:<input id="txtosecondMbs" NAME="txtosecondMbs" readonly /><br />
						DpbMbs（DPB宏块）:<input id="txtoDpbMbs" NAME="txtoDpbMbs" readonly /><br />
					</td>
					<td>
						fps（帧率）:<input id="txtofps" NAME="txtofps" readonly /><br />
						ref（参考帧数）:<input id="txtoref" NAME="txtoref" readonly /><br />
					</td>
				</tr>
			</table>
		</form>
		<p>Browser compatible: IE, FireFox, Chrome, Maxthon3...</p>
		<hr />
		<h3>Appendix A: Level Table</h3>
<table border="1" cellspacing="1" cellpadding="1" ID="tblref1"><colgroup> <col width="59" /> <col span="2" width="69" /> <col width="71" /> <col span="2" width="68" /> <col width="74" /> <col width="218" /></colgroup>
<tbody>
<tr>
<td rowspan="2" width="59" height="54">Level</td>
<td colspan="2" width="138">Max macroblocks</td>
<td colspan="4" width="281">Max video bit rate (kbit/s)</td>
<td rowspan="2" width="218">Examples for high resolution @ frame rate (max stored frames)</td>
</tr>
<tr>
<td width="69">per second</td>
<td width="69">per frame</td>
<td width="71">BP, XP, MP</td>
<td>HiP</td>
<td>Hi10P</td>
<td width="74">Hi422P, Hi444PP</td>
</tr>
<tr>
<td height="36">1</td>
<td align="right">1,485</td>
<td align="right">99</td>
<td align="right">64</td>
<td align="right">80</td>
<td align="right">192</td>
<td align="right">256</td>
<td width="218">128×96@30.9 (8)<br />176×144@15.0 (4)</td>
</tr>
<tr>
<td height="36">1b</td>
<td align="right">1,485</td>
<td align="right">99</td>
<td align="right">128</td>
<td align="right">160</td>
<td align="right">384</td>
<td align="right">512</td>
<td width="218">128×96@30.9 (8)<br />176×144@15.0 (4)</td>
</tr>
<tr>
<td height="54">1.1</td>
<td align="right">3,000</td>
<td align="right">396</td>
<td align="right">192</td>
<td align="right">240</td>
<td align="right">576</td>
<td align="right">768</td>
<td width="218">176×144@30.3 (9)<br />320×240@10.0 (3)<br />352×288@7.5 (2)</td>
</tr>
<tr>
<td height="36">1.2</td>
<td align="right">6,000</td>
<td align="right">396</td>
<td align="right">384</td>
<td align="right">480</td>
<td align="right">1,152</td>
<td align="right">1,536</td>
<td width="218">320×240@20.0 (7)<br />352×288@15.2 (6)</td>
</tr>
<tr>
<td height="36">1.3</td>
<td align="right">11,880</td>
<td align="right">396</td>
<td align="right">768</td>
<td align="right">960</td>
<td align="right">2,304</td>
<td align="right">3,072</td>
<td width="218">320×240@36.0 (7)<br />352×288@30.0 (6)</td>
</tr>
<tr>
<td height="36">2</td>
<td align="right">11,880</td>
<td align="right">396</td>
<td align="right">2,000</td>
<td align="right">2,500</td>
<td align="right">6,000</td>
<td align="right">8,000</td>
<td width="218">320×240@36.0 (7)<br />352×288@30.0 (6)</td>
</tr>
<tr>
<td height="36">2.1</td>
<td align="right">19,800</td>
<td align="right">792</td>
<td align="right">4,000</td>
<td align="right">5,000</td>
<td align="right">12,000</td>
<td align="right">16,000</td>
<td width="218">352×480@30.0 (7)<br />352×576@25.0 (6)</td>
</tr>
<tr>
<td height="72">2.2</td>
<td align="right">20,250</td>
<td align="right">1,620</td>
<td align="right">4,000</td>
<td align="right">5,000</td>
<td align="right">12,000</td>
<td align="right">16,000</td>
<td width="218">352×480@30.7(10)<br />352×576@25.6 (7)<br />720×480@15.0 (6)<br />720×576@12.5 (5)</td>
</tr>
<tr>
<td height="72">3</td>
<td align="right">40,500</td>
<td align="right">1,620</td>
<td align="right">10,000</td>
<td align="right">12,500</td>
<td align="right">30,000</td>
<td align="right">40,000</td>
<td width="218">352×480@61.4 (12)<br />352×576@51.1 (10)<br />720×480@30.0 (6)<br />720×576@25.0 (5)</td>
</tr>
<tr>
<td height="54">3.1</td>
<td align="right">108,000</td>
<td align="right">3,600</td>
<td align="right">14,000</td>
<td align="right">17,500</td>
<td align="right">42,000</td>
<td align="right">56,000</td>
<td width="218">720×480@80.0 (13)<br />720×576@66.7 (11)<br />1280×720@30.0 (5)</td>
</tr>
<tr>
<td height="36">3.2</td>
<td align="right">216,000</td>
<td align="right">5,120</td>
<td align="right">20,000</td>
<td align="right">25,000</td>
<td align="right">60,000</td>
<td align="right">80,000</td>
<td width="218">1,280×720@60.0 (5)<br />1,280×1,024@42.2 (4)</td>
</tr>
<tr>
<td height="54">4</td>
<td align="right">245,760</td>
<td align="right">8,192</td>
<td align="right">20,000</td>
<td align="right">25,000</td>
<td align="right">60,000</td>
<td align="right">80,000</td>
<td width="218">1,280×720@68.3 (9)<br />1,920×1,080@30.1 (4)<br />2,048×1,024@30.0 (4)</td>
</tr>
<tr>
<td height="54">4.1</td>
<td align="right">245,760</td>
<td align="right">8,192</td>
<td align="right">50,000</td>
<td align="right">62,500</td>
<td align="right">150,000</td>
<td align="right">200,000</td>
<td width="218">1,280×720@68.3 (9)<br />1,920×1,080@30.1 (4)<br />2,048×1,024@30.0 (4)</td>
</tr>
<tr>
<td height="36">4.2</td>
<td align="right">522,240</td>
<td align="right">8,704</td>
<td align="right">50,000</td>
<td align="right">62,500</td>
<td align="right">150,000</td>
<td align="right">200,000</td>
<td width="218">1,920×1,080@64.0 (4)<br />2,048×1,080@60.0 (4)</td>
</tr>
<tr>
<td height="90">5</td>
<td align="right">589,824</td>
<td align="right">22,080</td>
<td align="right">135,000</td>
<td align="right">168,750</td>
<td align="right">405,000</td>
<td align="right">540,000</td>
<td width="218">1,920×1,080@72.3 (13)<br />2,048×1,024@72.0 (13)<br />2,048×1,080@67.8 (12)<br />2,560×1,920@30.7 (5)<br />3,680×1,536@26.7 (5)</td>
</tr>
<tr>
<td height="54">5.1</td>
<td align="right">983,040</td>
<td align="right">36,864</td>
<td align="right">240,000</td>
<td align="right">300,000</td>
<td align="right">720,000</td>
<td align="right">960,000</td>
<td width="218">1,920×1,080@120.5 (16)<br />4,096×2,048@30.0 (5)<br />4,096×2,304@26.7 (5)</td>
</tr>
</tbody>
</table>
		
		<h3>Appendix B: MaxDpbMbs Table</h3>
<table border="1" cellspacing="1" cellpadding="1" ID="Table1"><colgroup> <col width="59" /> <col width="96" /></colgroup>
<tbody>
<tr>
<td width="59" height="18">Level</td>
<td width="96">MaxDpbMbs</td>
</tr>
<tr>
<td height="18">1</td>
<td align="right">396</td>
</tr>
<tr>
<td height="18">1b</td>
<td align="right">396</td>
</tr>
<tr>
<td height="18">1.1</td>
<td align="right">900</td>
</tr>
<tr>
<td height="18">1.2</td>
<td align="right">2,376</td>
</tr>
<tr>
<td height="18">1.3</td>
<td align="right">2,376</td>
</tr>
<tr>
<td height="18">2</td>
<td align="right">2,376</td>
</tr>
<tr>
<td height="18">2.1</td>
<td align="right">4,752</td>
</tr>
<tr>
<td height="18">2.2</td>
<td align="right">8,100</td>
</tr>
<tr>
<td height="18">3</td>
<td align="right">8,100</td>
</tr>
<tr>
<td height="18">3.1</td>
<td align="right">18,000</td>
</tr>
<tr>
<td height="18">3.2</td>
<td align="right">20,480</td>
</tr>
<tr>
<td height="18">4</td>
<td align="right">32,768</td>
</tr>
<tr>
<td height="18">4.1</td>
<td align="right">32,768</td>
</tr>
<tr>
<td height="18">4.2</td>
<td align="right">34,816</td>
</tr>
<tr>
<td height="18">5</td>
<td align="right">110,400</td>
</tr>
<tr>
<td height="18">5.1</td>
<td align="right">184,320</td>
</tr>
</tbody>
</table>

	</body>
</html>

    下载地址——

    https://files.cnblogs.com/zyl910/h264_level_calculator.rar
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  • 原文地址：https://www.cnblogs.com/zyl910/p/h264_level_calculator.html
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