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Activity Forums Compression Techniques Determining Target bitrate from Broadcast Specs (Comcast Ad Delivery)

  • Determining Target bitrate from Broadcast Specs (Comcast Ad Delivery)

    Posted by David Bitterman on November 5, 2015 at 10:21 pm

    I’m trying to figure out how to setup my Adobe Media Encoder preset for several broadcast specifications and realized that my understanding of broadcast bitrate is lacking. So, in the spec below which was given to us by comcast ad delivery, it specifies a bitrate (CBR or VBR) of between 20-100. I can obviously set VBR bitrate min to 20 and max to 100, but what should I be setting Target at? Who ultimately benefits from setting target higher vs lower, and besides that, what’s a good average setting for HD broadcast?

    Any and all help is much appreciated!

    MPEG-2 Transport Stream

    20 – 100 Mbps (CBR or VBR)

    29.97 (1080i), 59.94 (720p)

    Closed GOP

    EIA-608 and EIA-708

    4:2:0

    Upper Field First (1080i), Progressive (720p)

    16:9

    1920×1080 (1080i), 1280×720 (720p)

    MPEG-1 Layer 2

    MP@HL HP@HL

    Ted Bragg replied 10 years, 5 months ago 2 Members · 1 Reply
  • 1 Reply
  • Ted Bragg

    November 9, 2015 at 8:14 pm

    I’ve submitted 96Mbps CBRs with no problem. They run everything through their sledgehammer compression system, so no matter how masterfully you prep a file, it’ll be a macroblocked quilt by the time it hits their SD channels.

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