Transcoding can't exit in ffmpeg transcoding server even if input rtmp streaming was finished broadcasting.

[wangjingz]

To Reproduce

1. Use ffmpeg upstreaming stream as input media content to xcode server and do transcoding, command line such as:

ffmpeg -re -i /media/_System_Validation/mp4_h264aac/h264_1920x1080_b@40_2397_8225kbps_cbr_aac_lc_256kbps_48000_hd_the_living_see_2mn48s.mp4 -c:v copy -f flv rtmp://192.168.31.32/stream/xcode

2. in Xcode server, use ffmpeg to do transcoding and rtmp streaming to nginx server which can transformat DASH/HLS segments, command line such as:

 ffmpeg -i rtmp://192.168.31.32/stream/xcode -s 4096*2160 -c:a copy -c:v libsvt_hevc -preset 10 -maxrate 4000000 -r 30 -f flv rtmp://192.168.31.31/dash/

3. ffmpeg Xcode server can't exit transcoding even if input rtmp streaming is finishing broadcasting.

Expected behavior
In transcoding server, ffmpeg should exit if the input streaming was finished broadcasting.

[TangZhiZhen]

it looks like ffmpeg vaapi issue, will submit issue into ffmpeg.

[xinglongx]

still exist in the lastest code