I wasn't sure whether or not to post this in the DVB/HDTV forum as it pertains to ATSC, but I wasn't sure.
Anyway, I am doing closed-circut ATSC broadcasting and am wondering how I can fine tune my encoding. Right now I am using FFMPEG as I cannot find a hardware encoder for MPEG-2; and this is what I have going so far (Source fps is 30):
This looks fairly good for the most part, but for detailed scenes and particularly fast shots, it gets somewhat strained. The q never goes below 30, but I'd like to see what I can do to make this as optimized as possible. The source is a live 1080p feed that consists of upscaled 480, 720, source 1080, and 4K. I have tried 1080i as well, but the results were muddied with artifacts.Code:ffmpeg -re -i "INPUT" -vcodec mpeg2video -pix_fmt yuv420p \ -me_method epzs -re -g 15 -trellis 0 -cmp 2 -subcmp 2 -s 1920x1080 -vb 16.9M -bufsize 5995392 -me_method epzs \ -minrate:v 16.9M -maxrate:v 17.25M -streamid 0:260 -y -f mpeg2video /tmp/video.es -acodec ac3 -ab 224k -streamid 1:265 -y -f ac3 /tmp/audio.es
To fit within my ATSC mux, it must stay under 17.5 MB/s. Any ideas?
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8-VSB speed (netto - whole feed) is 19.3904Mbps, deinterlace and prefilter video, allow bitrate to be more variable, go for faster PC and use more features such as trellis. Anyway 1080 and 19Mbps is kind of demanding task even for non real time encoder.
First enable interlace coding in ffmpeg (seem it is not enabled), second - going to progressive gives around 30% bitrate (quality) gain in MPEG-2
And, it could be my muxer (Opencaster), I'll fiddle with some things and see if I can get a little more headroom for the bitrate. Any affordable PSIP generation/muxing software you can think of?
there is no good open source and realtime muxer for TS thus i can't propose anything...