胡斌 / merge_av_release

1.在录像信息文件里没有老师视频或学生视频时，把老师视频或学生视频的大小设为320x240，避免在一对多布局时出现错误
git@123.56.226.173:hubin/merge_av.git  master分支
commit 91b5db84a4d0cb3a0db5813f61c70e02afbd663c

1.支持读取编码配置文件，用于改变编码配置

git@123.56.226.173:hubin/merge_av.git master分支
commit  e9399dfb28ee0209b6aebca1e342af22e6708cd8

1.没有老师，但是有两个学生时，默认使用一对多布局
2.一对一时，老师和学生的视频尺寸不同时，合成的视频高度取老师视频高度加上学生视频高度（之前版本假定老师和学生视频大小一致，使用的是最大高度的二倍）
3.一对多时，支持学生的视频尺寸不一致的情况（之前版本假定只有一种视频尺寸，其它尺寸视为异常）
4.一对多时，最多只在老师视频下部排4个学生，多于4个学生的情况，扩大合成视频的高度，把学生视频排列在老师视频下方，保证老师视频部分最多只有一排学生视频，避免老师视频被过度遮挡
git@123.56.226.173:hubin/merge_av.git master分支
commit c160aaa944ab354a552b189136b4d5a563f27c08

1.修改学生视频为320x240，老师的视频为240x180时，老师背景有花屏
2.修改老师和学生视频都为240x180视频时，视频宽度仍为240, 且有花屏
3.只有一路视频时，默认合成为上下布局

git@123.56.226.173:hubin/merge_av.git master分支
commit bcfdf44a86ec735920c73351ee669688661f63d0

source git: git@123.56.226.173:hubin/merge_av.git
commit d41aa4eb5f1acc4ca4fbeb7b5ec72110b0a3c80f

source git: git@123.56.226.173:hubin/merge_av.git
commit 43f3ebe0f5f96b82d0f43550f07f7cd0f3be572a

source git: git@123.56.226.173:hubin/merge_av.git
commit 85a1de676e8f2a03541642f87e2e9d6e6d0531a2

if source video codec is h264,default action is don't recodec when transcode to ts if -t is not specified

source commit 04e7b37e25293bed35580b11be0c6b5293129487

get the correct duration of mp4 files

using the name exclude extended name of first audio or video as the name for the output ts file

read recordinfo.txt,transcode ,and save recordinfo_out.txt
in previous version,all the audio an video are merged to one ts,
in this version,there are maybe serveral ts,if the video file or audio file is not continuous

support 1 video mixing with multi-segments audio file

support the record file only have video

1.using the video duration parsed from video file
2.make compatiable with the recording file with the start time not being zero
3.merge with blank jpg for the last segment audio without video
4.adjust video codec param ,using cfr, 20fps,gop 100