Creative Communities of the World Forums

The peer to peer support community for media production professionals.

Activity › Forums › Compression Techniques › GOP – Open vs Closed for Streaming File

  • Compression Techniques

    GOP – Open vs Closed for Streaming File

    Posted by Emanuel Ach on March 9, 2011 at 1:03 am

    Hi,

    So im using Mac with Snow :P, running FCP studio 3 and the original files are DV. I will export everything to MPEG-2 (mpeg) so I am trying to improve the quality of the final product video (it’s for broadcasting on satellite). While I am aware of the fact that GOP open improves it a little, I am not aware how much it will affect in this circumstance:

    We have 1 file 50min long. We stop it at let’s say 25min14sec play some ads and resume from the 25min14sec (maybe the next second, I dunno). And we do this for like 3 times for that file. What’s my best option?

    I actually have more questions:

    1) Is there any real advantage if I choose field dominance: progressive (is this going to change the frame rate to 24?)?
    2) Will “Two pass VBR Best” cause any problems on the broadcast? (just in case I miss something)
    3) What’s with the YUV 4:2:2 color encoding, option in “Compressor”? How can compressor take DV that is 4:1:1 and make it 4:2:2 (when the information is not there?) ? If that’s enabled is there really going to improve the quality?
    4) Are any of those filters in compressor useful for something?

    PS this file won’t be for DVDs just broadcasting.

    Thanks.

    Jeff Greenberg replied 15 years, 2 months ago 3 Members · 3 Replies
  • 3 Replies

  • Craig Seeman

    March 9, 2011 at 1:09 am

    You really need to speak to the Satellite distributor since everything they send is likely to a single standard. I seriously doubt they’d support Open GOP. It can create all sorts of stream recovery issues for the viewer.

  • Emanuel Ach

    March 9, 2011 at 5:12 pm

    Well, just for my knowledge, let’s leave the broadcast part aside, so for an mpeg that is not for DVD, what helps from my 1st post?

  • Jeff Greenberg

    March 10, 2011 at 4:24 am

    [Emanuel Ach] “1) Is there any real advantage if I choose field dominance: progressive (is this going to change the frame rate to 24?)?
    2) Will “Two pass VBR Best” cause any problems on the broadcast? (just in case I miss something)
    3) What’s with the YUV 4:2:2 color encoding, option in “Compressor”? How can compressor take DV that is 4:1:1 and make it 4:2:2 (when the information is not there?) ? If that’s enabled is there really going to improve the quality?
    4) Are any of those filters in compressor useful for something?”

    1) no, keep the file interlaced if it was interlaced. If the frame rate was 24, it might be progressive.
    2) Might – depends on the broadcast specs.
    3) Actually, it interpolates the missing information. It’s just upsampling. And DVDs are 4:2:0
    4) Yes.

    Best,

    Jeff G

    Apple Master Trainer | Avid Cert. Instructor DS/MC
    Come See me speak at NAB!
    Compressor Essentials from Lynda.com
    (older but still good) Marquee, Media Composer (3.5) and Basic/Advanced Color DVDs (1.0) from Vasst.com
    Contact me through my Website

Reply to this Discussion! Login or Sign Up

We use anonymous cookies to give you the best experience we can.
Our Privacy policy | GDPR Policy