[FFmpeg-devel] What is the problem with my transcoding?

[fangzhen]

Hi guys,

Recently, I am doing some transcoding using ffmpeg. The input protocol is udp and output is HLS.
The command line is the following:
ffmpeg -hide_banner -threads auto -y -xerror -itsoffset 0.5 -async 1 -i udp://127.0.0.1:48882?overrun_nonfatal=1&buffer_size=100000000&fifo_size=100000000 -map p:3801 -vf movie='/home/u    buntu/codec/logo/zb_67.tga',scale=279.0:69.0[logo];[in][logo]overlay=main_w-overlay_w-96.0:54.0[out] -c:v libx264 -preset superfast -level:v 5.1 -s 1280x720 -r 25 -x264-params keyint=50    :scenecut=0 -b:v 1072k -c:a libfdk_aac -profile:a aac_low -b:a 128k -ac 2 -ar 44100 -hls_wrap 0 -hls_time 10 -hls_list_size 15 -hls_flags round_durations -hls_segment_filename /home/ubu    ntu/codec/release/hlstemp/20160304104101-01-%d.ts -start_number 1457059261 /home/ubuntu/codec/release/hlstemp/01.m3u8·

However, when the transcoder runs some time later, the ouput frames are abnormal, a lot of mosaic appears and sometimes the picture stalls for about 5 seconds.
There are some logs of transcoder:
[Parsed_overlay_2 @ 0x1e16100] [framesync @ 0x1e161e8] Buffer queue overflow, dropping.
[Parsed_overlay_2 @ 0x1ea9720] [framesync @ 0x1ea9868] Buffer queue overflow, dropping.
[Parsed_overlay_2 @ 0x1e16100] [framesync @ 0x1e161e8] Buffer queue overflow, dropping.
[Parsed_overlay_2 @ 0x1ea9720] [framesync @ 0x1ea9868] Buffer queue overflow, dropping.
[Parsed_overlay_2 @ 0x1e16100] [framesync @ 0x1e161e8] Buffer queue overflow, dropping.
[Parsed_overlay_2 @ 0x1ea9720] [framesync @ 0x1ea9868] Buffer queue overflow, dropping.
.........
[h264 @ 0x9b1f7e40] left block unavailable for requested intra4x4 mode -1 at 0 6
[h264 @ 0x9b1f7e40] error while decoding MB 0 6, bytestream 47923
[h264 @ 0x9b1f7e40] concealing 7489 DC, 7489 AC, 7489 MV errors in I frame
[h264 @ 0x9adf6260] Reference 3 >= 2
[h264 @ 0x9adf6260] error while decoding MB 10 8, bytestream 65855
[h264 @ 0x9adf6260] concealing 7239 DC, 7239 AC, 7239 MV errors in P frame
[mpegts @ 0x3ad0880] PES packet size mismatch
[ac3 @ 0x3face00] exponent out-of-range
[ac3 @ 0x3face00] error decoding the audio block
[ac3 @ 0x3face00] frame sync error

Can anyone help me to find out why?

Thinks in advance
Felix Hu