胡斌 / merge_av_release

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

git@123.56.226.173:hubin/merge_av.git
commit 6a66277676bf4e32b7866bd736ca02bd34d527fc