http://blog.csdn.net/jasonhwang/article/details/7359095
抓取一个包含H.264 Payload RTP包的SIP会话或RTSP会话后，用Wireshark的Play功能只能播放声音，不能播放视频。把payload直接导出成文件后也是不能直接播放的，因为H.264 over RTP封包是符合RFC3984规范的，必须按照该规范把H.264数据取出来后，组成NALU，放到avi/mp4或裸码流文件等容器里后才能播放。

本人写了一个wireshark插件，可以在打开包含H.264码流的抓包后，选菜单“Tools->Export H264 to file [HQX's plugins]”后，把抓包文件里的H.264码流自动导出到抓包文件所在目录（工作目录）里，名为from_<RTP流源 ip>_<RTP流源端口>_to_<RTP流目的ip>_<RTP流目的端口>.264的264裸码流文件 里。（文件格式为每个NALU前加0x00000001分隔符）。

本程序可以识别RFC3984里提到的三种H.264 over RTP封装，分别是Single NALU（一个RTP含一个NALU）、STAP-A（一个RTP包含多个NALU）、FU-A（一个NALU分布到多个RTP包）三种封装格式，且会自 动把SPS和PPS放到裸码流文件头部。

Lua脚本如下：

-- Dump RTP h.264 payload to raw h.264 file (*.264)-- According to RFC3984 to dissector H264 payload of RTP to NALU, and write it-- to from<sourceIp_sourcePort>to<dstIp_dstPort>.264 file. By now, we support single NALU,-- STAP-A and FU-A format RTP payload for H.264.-- You can access this feature by menu "Tools->Export H264 to file [HQX's plugins]"-- Author: Huang Qiangxiong (qiangxiong.huang@gmail.com)-- change log:--      2012-03-13--          Just can play------------------------------------------------------------------------------------------------do-- for geting h264 data (the field's value is type of ByteArray)local f_h264 = Field.new("h264") -- menu action. When you click "Tools->Export H264 to file [HQX's plugins]" will run this functionlocal function export_h264_to_file()-- window for showing informationlocal tw = TextWindow.new("Export H264 to File Info Win")local pgtw = ProgDlg.new("Export H264 to File Process", "Dumping H264 data to file...")-- add message to information windowfunction twappend(str)tw:append(str)tw:append("\n")end-- running first time for counting and finding sps+pps, second time for real savinglocal first_run = true -- variable for storing rtp stream and dumping parameterslocal stream_infos = {}-- trigered by all h264 packatslocal my_h264_tap = Listener.new(tap, "h264")-- get rtp stream info by src and dst addressfunction get_stream_info(pinfo)local key = "from_" .. tostring(pinfo.src) .. "_" .. tostring(pinfo.src_port) .. "to" .. tostring(pinfo.dst) .. "_" .. tostring(pinfo.dst_port)local stream_info = stream_infos[key]if not stream_info then -- if not exists, create onestream_info = { }stream_info.filename = key.. ".264"stream_info.file = io.open(stream_info.filename, "wb")stream_info.counter = 0 -- counting h264 total NALUsstream_info.counter2 = 0 -- for second time runningstream_infos[key] = stream_infotwappend("Ready to export H.264 data (RTP from " .. tostring(pinfo.src) .. ":" .. tostring(pinfo.src_port) .. " to " .. tostring(pinfo.dst) .. ":" .. tostring(pinfo.dst_port) .. " to file:\n         [" .. stream_info.filename .. "] ...\n")endreturn stream_infoend-- write a NALU or part of NALU to file.function write_to_file(stream_info, str_bytes, begin_with_nalu_hdr)if first_run thenstream_info.counter = stream_info.counter + 1if begin_with_nalu_hdr then-- save SPS or PPSlocal nalu_type = bit.band(str_bytes:byte(0,1), 0x1F)if not stream_info.sps and nalu_type == 7 thenstream_info.sps = str_byteselseif not stream_info.pps and nalu_type == 8 thenstream_info.pps = str_bytesendendelse -- second time runningif stream_info.counter2 == 0 then-- write SPS and PPS to file header firstif stream_info.sps thenstream_info.file:write("\00\00\00\01")stream_info.file:write(stream_info.sps)elsetwappend("Not found SPS for [" .. stream_info.filename .. "], it might not be played!\n")endif stream_info.pps thenstream_info.file:write("\00\00\00\01")stream_info.file:write(stream_info.pps)elsetwappend("Not found PPS for [" .. stream_info.filename .. "], it might not be played!\n")endendif begin_with_nalu_hdr then-- *.264 raw file format seams that every nalu start with 0x00000001stream_info.file:write("\00\00\00\01")endstream_info.file:write(str_bytes)stream_info.counter2 = stream_info.counter2 + 1if stream_info.counter2 == stream_info.counter thenstream_info.file:flush()twappend("File [" .. stream_info.filename .. "] generated OK!\n")end-- update progress window's progress barif stream_info.counter > 0 then pgtw:update(stream_info.counter2 / stream_info.counter) endendend-- read RFC3984 about single nalu/stap-a/fu-a H264 payload format of rtp-- single NALU: one rtp payload contains only NALUfunction process_single_nalu(stream_info, h264)write_to_file(stream_info, h264:tvb()():string(), true)end-- STAP-A: one rtp payload contains more than one NALUsfunction process_stap_a(stream_info, h264)local h264tvb = h264:tvb()local ffset = 1repeatlocal size = h264tvb(offset,2):uint()write_to_file(stream_info, h264tvb(offset+2, size):string(), true)ffset = offset + 2 + sizeuntil offset >= h264tvb:len()end-- FU-A: one rtp payload contains only one part of a NALU (might be begin, middle and end part of a NALU)function process_fu_a(stream_info, h264)local h264tvb = h264:tvb()local fu_idr = h264:get_index(0)local fu_hdr = h264:get_index(1)if bit.band(fu_hdr, 0x80) ~= 0 then-- start bit is set then save nalu header and bodylocal nalu_hdr = bit.bor(bit.band(fu_idr, 0xE0), bit.band(fu_hdr, 0x1F))write_to_file(stream_info, string.char(nalu_hdr), true)else-- start bit not set, just write part of nalu bodyendwrite_to_file(stream_info, h264tvb(2):string(), false)end-- call this function if a packet contains h264 payloadfunction my_h264_tap.packet(pinfo,tvb)local h264s = { f_h264() } -- using table because one packet may contains more than one RTPfor i,h264_f in ipairs(h264s) doif h264_f.len < 2 thenreturnendlocal h264 = h264_f.value   -- is ByteArraylocal hdr_type = bit.band(h264:get_index(0), 0x1F)local stream_info = get_stream_info(pinfo)if hdr_type > 0 and hdr_type < 24 then-- Single NALUprocess_single_nalu(stream_info, h264)elseif hdr_type == 24 then-- STAP-A Single-time aggregationprocess_stap_a(stream_info, h264)elseif hdr_type == 28 then-- FU-Aprocess_fu_a(stream_info, h264)elsetwappend("Error: unknown type=" .. hdr_type .. " ; we only know 1-23(Single NALU),24(STAP-A),28(FU-A)!")endendend-- close all open filesfunction close_all_files()if stream_infos thenfor id,stream in pairs(stream_infos) doif stream and stream.file thenstream.file:close()stream.file = nilendendendendfunction my_h264_tap.reset()-- do nothing nowendfunction remove()close_all_files()my_h264_tap:remove()endtw:set_atclose(remove)-- first time it runs for counting h.264 packets and finding SPS and PPSretap_packets()first_run = false-- second time it runs for saving h264 data to target file.retap_packets()-- close progress windowpgtw:close()end-- Find this feature in menu "Tools->"Export H264 to file [HQX's plugins]""register_menu("Export H264 to file [HQX's plugins]", export_h264_to_file, MENU_TOOLS_UNSORTED)end

把代码保存成h264_export.lua文件，放到wireshark安装目录下，然后修改wireshark安装目录下的init.lua文件：

（1）若有disable_lua = true这样的行，则注释掉；

（2）在文件末加入dofile("h264_export.lua")

重新打开wirekshark就能使用该功能了。（低版本的wireshark可能不支持此功能，升级到最新版本即可）

生成的文件在桌面。

另外，264裸码流文件一般播放器不一定能播放，推荐使用ffmpeg的ffplay播放，或用ffmpeg转成通用文件格式播放。

我用的是Elecard_StreamEye测试的，生成的包正常播放。