Key to the smooth running of any broadcast operation is the delivery of the content from post-production facilities in the correct format. Most commissioning broadcasters have a detailed delivery specification that lays down the media of choice (tape format), scanning format (720P, 1080I) and audio track layout. There are many other parameters that will be listed including: caption format, AFD and loudness metadata. But, looking forward, the videotape delivery specification was pretty straightforward.
Move to delivering programs and commercials as files, however, and it gets a lot more complex. Many parameters remain the same, like AFD and scanning format. But, the use of a file adds many more variables such as which codec should be used. With tape, the codec is internal to the recording system; it’s like a black box with SDI in and out of the deck.
Then, there is the matter of the wrapper: QuickTime, GXF and MXF are all possible candidates. Dig deeper into the detail, and that is where the devil lies. Should data be multiplexed or interleaved? Should audio be one multichannel track or multiple single-channel tracks? Where should the timecode be stored in the wrapper? And, what about closed captions?
Source: Broadcast Engineering