On Wed, Jan 15, 2025 at 1:29 AM Greg Oliver <oliver.g...@gmail.com> wrote:
> On Tue, Jan 14, 2025 at 11:37 AM Shane Warren <sha...@innovsys.com> wrote: > > > > I am transcoding live multicast using hardware (decoding using nvidia > and encoding using nvidia (h264_nvenc) and going out multicast at fixed > framerate and constant bitrate. Normally the output is about 3-5 seconds > behind the input. > > > > I have some streams that cause the output to eventually get minutes > behind the input. I've narrowed down the input buffering being the culprit > of holding a very large buffer of input frames in these situations. > > > > Here is my command: > > > > ffmpeg -y -threads 2 -nostats -nostdin -loglevel verbose -progress > pipe:1 -probesize 5M -filter_threads 4 -threads 2 -re -fflags +genpts > -fflags discardcorrupt -hwaccel_device 0 -extra_hw_frames 2 > -hwaccel_output_format cuda -hwaccel cuda -heavy_compr 1 -thread_queue_size > 512 -i "udp://@ > 225.105.0.27:10102?fifo_size=1073440&buffer_size=2129920&timeout=800000" > -autoscale 0 -threads 2 -filter_complex > "[0:v:0]fps=30000/1001,yadif_cuda,scale_npp=1920:1080:interp_algo=super:format=yuv420p > [vout]" -map "[vout]" -map "0:a:0" -map 0:d? -filter:a:0 > "aresample=async=10000,volume=1.00" -c:a:0 aac -threads 2 -ac:a:0 2 > -ar:a:0 48000 -b:a:0 192k -flush_packets 0 -c:v h264_nvenc -b:v 6000k > -minrate:v 6000k -maxrate:v 6000k -bufsize:v 12000k -a53cc 1 -tune ll > -zerolatency 1 -cbr 1 -forced-idr 1 -strict_gop 1 -threads 2 -profile:v > high -level:v 4.2 -bf:v 0 -g:v 15 -f fifo -drop_pkts_on_overflow 1 > -attempt_recovery 0 -fifo_format mpegts -format_opts > muxrate=6800440:pes_payload_size=1528 "udp://@225. > > 105.0.65:10102?pkt_size=1316&bitrate=6800440&burst_bits=10528&ttl=64" > > > > I suspect the input stream does something odd and causes ffmpeg to > buffer frames and it gets slowly behind. I would like to make ffmpeg drop > frames if possible, instead of forever buffering frames and getting further > and further out of sync. > > > > Is there anything anyone can recommend to force ffmpeg to stop buffering > input frames? > > I imagine the stream is changing somehow. What is the output (ffmpeg) > when it happens? Also, maybe try starting simple (-preset 8) and > then fine tuning. > Hi! I would try to remove -re flag from input, so it don't buffer excess received frames. It may cause some other frame rate inaccuracies in output though. Maybe it works. Vilnis > _______________________________________________ > ffmpeg-user mailing list > ffmpeg-user@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe". > _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
