VideoHelp Forum

+ Reply to Thread
Page 2 of 2
FirstFirst 1 2
Results 31 to 37 of 37
Thread
  1. Capturing Memories dellsam34's Avatar
    Join Date
    Jan 2016
    Location
    Member Since 2005, Re-joined in 2016
    Search PM
    So what was the OP's question?
    Quote Quote  
  2. Member DB83's Avatar
    Join Date
    Jul 2007
    Location
    United Kingdom
    Search Comp PM
    Originally Posted by dellsam34 View Post
    So what was the OP's question?

    Quote Quote  
  3. Member
    Join Date
    Nov 2021
    Location
    Melbourne, Victoria, Australia
    Search Comp PM
    Again:

    Is this conversion what D.V.D players do on playback using a T.V set or video monitor programmed for interlaced scanning? Is this also what television stations did to what they broadcast once fully converted to digital video internally?
    Did a lot of television content from the late 1990s, if not shot on film, originate at 25p or 30p at a higher resolution than even 576 lines and get downconverted to 480i or 576i for broadcast?

    Some of the comments don't clearly answer this.

    576p25 is 25 frames per second, each with 576 lines. 576i50 is 50 fields per second each with 288 lines. Two 288 line fields make one 576 line frame. The only difference between these two standards is the order of the lines.

    My question about D.V.Ds concerns the order in which the lines of each frame are stored on the disc. In the digital domain, this can easily be changed with frame buffers.
    Quote Quote  
  4. Member DB83's Avatar
    Join Date
    Jul 2007
    Location
    United Kingdom
    Search Comp PM
    I'll just address your last, now added, question.


    Dvds are mpeg2. And mpeg2 on dvd is, as understand it, TOP FIELD FIRST


    As for the rest, if you are not satisfied with what has been told to you then it is probably beyond the technical knowledge of even the most technically knowledgeable people in these forums. Find a forum that discusses broadcast television or contact a broadcaster direct.


    But why should it even matter these days ?
    Quote Quote  
  5. Member Skiller's Avatar
    Join Date
    Oct 2013
    Location
    Germany
    Search PM
    Originally Posted by Xanthipos View Post
    My question about D.V.Ds concerns the order in which the lines of each frame are stored on the disc.
    They are stored in frames, so basically, as DB83 said, Top First, line 1 to 576. If the actual field order of the content is the opposite, this is indicated by a flag and only used during playback. The video's actual field order does not matter for quantization in an interlaced frame structure. By using "Alternate" scan during quantization the lines of the two fields are kept perfectly separate, even if the bitrate is so low that the whole video is a blocky mess. Interlace would still be intact.

    MPEG2 also has an option of storing each field separately rather than in an interlaced frame structure (indicated by the "Picture structure" attribute), but that is never used due to bad compatibility (on DVD). Most MPEG2 encoders don't even have the option to encode field based but it is possible.
    Quote Quote  
  6. Capturing Memories dellsam34's Avatar
    Join Date
    Jan 2016
    Location
    Member Since 2005, Re-joined in 2016
    Search PM
    Originally Posted by Xanthipos View Post
    Is this conversion what D.V.D players do on playback using a T.V set or video monitor programmed for interlaced scanning? Is this also what television stations did to what they broadcast once fully converted to digital video internally?
    Did a lot of television content from the late 1990s, if not shot on film, originate at 25p or 30p at a higher resolution than even 576 lines and get downconverted to 480i or 576i for broadcast?
    First you can just write DVD and TV no need to D.V.D and T.V.

    Broadcast studios and production houses used different techniques of interlacing and de-interlacing depends on the material at hand and the target format or the broadcast method of the that time, most of them are documented in technical literatures over the internet starting with Wikipedia. If you have a specific question about a show or a movie then you can use a thread like this to discuss it otherwise it's just like saying guys let's discuss astronomy here. That's not how forum threads work.
    Quote Quote  
  7. Member DB83's Avatar
    Join Date
    Jul 2007
    Location
    United Kingdom
    Search Comp PM
    +1


    Once you ask more than one question it 'smells' of topic-hijacking and makes a topic rather hard to follow.


    So here is a link (there will be others) that discusses the change from analog(ue) to digital.


    https://en.wikipedia.org/wiki/Digital_television


    And more than interesting to note that broadcasters preferred interlaced over progressive for the reasons so expressed.
    Quote Quote