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  1. 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):

    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
    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.

    To fit within my ATSC mux, it must stay under 17.5 MB/s. Any ideas?
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  2. 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.
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  3. Originally Posted by pandy View Post
    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.
    After PSIP tables, I only have about ~18 MB/s remaining. I'll look into trellis. You mention deinterlscong. Is there any way to do 1080i, and have it not be riddled with noise and artifacts, or is that just the mature of interlaced? As of right now, the 1080p looks great for things like animation and movies; even news features. I just want to improve it in any way I can given the constraints.
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  4. 1Mbps PSI/SI?

    First enable interlace coding in ffmpeg (seem it is not enabled), second - going to progressive gives around 30% bitrate (quality) gain in MPEG-2

    http://smorgasbork.com/component/content/article/97-real-time-mpeg-2-encoding-with-ffmpeg
    http://forum.videohelp.com/threads/356455-FFmpeg-and-mpeg2-interlaced-encoding
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  5. Originally Posted by pandy View Post
    1Mbps PSI/SI?

    First enable interlace coding in ffmpeg (seem it is not enabled), second - going to progressive gives around 30% bitrate (quality) gain in MPEG-2

    http://smorgasbork.com/component/content/article/97-real-time-mpeg-2-encoding-with-ffmpeg
    http://forum.videohelp.com/threads/356455-FFmpeg-and-mpeg2-interlaced-encoding
    Ironic you post those, because I have tried both in my setup. Interlacing gives horrific artifacts that progressive does not. I can give it another go I suppose, but last I tried that; it didn't work so well.

    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?
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  6. Originally Posted by jowijo View Post
    Ironic you post those, because I have tried both in my setup. Interlacing gives horrific artifacts that progressive does not. I can give it another go I suppose, but last I tried that; it didn't work so well.

    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?
    you need to tell encoder that source is interlace (and define if this is TFF or BFF - assume in Your case BFF) - but anyway with this bitrate progressive (deinterlaced interlace source) encoding is recommended.

    there is no good open source and realtime muxer for TS thus i can't propose anything...
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