Request: PGS Subtitles default position in HT4

Discussion in 'HDD Media player(RTD 1619DR)' started by Bello78, Dec 31, 2020.

  1. Bello78

    Bello78 New Member


    First of all, I would like to thank all the Zidoo team for their great work. I really like my Zidoo Z9X.

    - watch all the movie using PGS subtitles on my UHD ISO/BDMV BR backup libraries
    - using a 2.40 screen that can be converted to 16/9.

    there is no “default or global” configuration for the subtitle position. In case my screen is in 2.40, I’ve to set the subtitle position for each movie play for the first time with the position 90.
    On the other side, the subtitle brightness setting is correctly kept.

    Request proposal:
    Must have: a “default” position subtitle setting in HT4 that will be used for all movies.
    Nice to have: possibility to have different subtitle settings profiles (for me will create one for 2.40 and one for 16/9) that could be selected either automatically against predefined filter or using the IP control. On the Oppo it was possible using the Ip control to send the subtitle position using integer value.

    I’m sure I’m not the only one waiting for this feature
    Thanks a lot
  2. Bello78

    Bello78 New Member

    Ok after testing more deeply, the PGS subtitles position depends on the PGS offset used by the studio/editor.
    For example, Warner movies use a PGS subtitle offset that renders the subtitle partially in the black bar (as for most streaming application unfortunately). Most of other studios/editors place them inside the movie.

    So it’s not something coming from the Zidoo. The only possible solution should be to analyze this offset and check the movie format in order to change the default offset to ensure the subtitle are located inside the movie, but clearly I’m not sure Zidoo team could do it.
    Last edited: Jan 2, 2021
  3. OlivierQC

    OlivierQC Well-Known Member

    Hello Bello78,

    Let's hope Zidoo Team see your post and gives a response, you never know, they are good at finding solutions :)

    See you
    Bello78 likes this.
  4. Whitfield

    Whitfield Active Member

    One is dependent on how the PGS streams are authored, correct. Therefor, it would not be possible to tell a player a "default preference".

    PGS streams are image-based. So there is no text in a PGS, just pictures containing text. Most of these pictures are encoded as big as the text-box itself and the positioning is done by assigning X/Y coordinates (or indeed, as you call them, "offsets") to it, so the player "knows" where to display them. In these cases, and when the player is able, the subtitle can be moved around to some extent.
    There are also so-called "full screen" PGS streams, where the whole subtitle picture has the full videoresolution 1920x1080. Most of the image is fully transparent, only the "text" is encoded more opaque. These type of subtitles cannot be moved around.

    Things get tricky where video and subtitle are not standardized and start to drift apart.
    For example, Take a 1920x1080 video which contains a 2.40:1 movie. Often these are cropped (taking away the black bars) to 1920x800 and then recoded. Should you mux this kind of video with the original, 1920x1080 PGS stream, a player must know that the 1920x800 video is "supposed to be 1920x1080 with black bars" and the PGS @1920x1080 should be overlayed accordingly.
    Most players "understand" this and act properly. Some don't and squish the 1920x1080 SUP into the 1920 x 800 "movie-only" picture, giving all kinds of nasty, unmeant displays. (SUP is commonly used; it's the extension of a demuxed PGS stream when you work with them)

    With the same video as above, another option would be to create a PGS stream with a resolution that fits the video; so in this case 1920x800. Sometimes players react well on these and will properly display the subtitles as they were meant: in the 1920x800 video area. Some players however go hopelessly lost and stretch up vertically to 1920x1080. Again, resulting in awful displays.

    With 4K video things can get more crazy. Note that - according to UHD-BD specs - the SUPs on a UHD blu-ray (3840x2160 video) are authored in 1920x1080 (!). When you want to crop & re-encode 4K in say 3840x1600, a player can totally loose the meaning of it all. And when diffent video-codecs, colorspaces, anamorphic video-encoding and other none-compliant resolutions come into play, hell's loose.
    It's all in the ability to read mediaproperties, -headers & -tags correctly, interpret them properly and accordingly write your firmware to it.

    I do a lot of subtitle editing & creating. I have noticed several issues with my Z9X, but I need time to exactly pin down on what occasion this or that goes wrong.
    One of the buggiest issues I have with the Zidoo, is that I can not create mkv's with embedded *.ASS subtitles that will work. No matter what I do. Annoying nonsense, as older players - build in times when the world merely existed of flesh and teeth - know this trick already.
  5. Bello78

    Bello78 New Member

    Thanks a lot for all those information!
    It’s clear that implementing such a request for UHD is really challenging (maybe too much)
  6. Whitfield

    Whitfield Active Member

    Well, it must be possible technically in the first place. To establish that possibility, as said, you have to be able and read the media properties in the first place. With the Z9X having a music player that is not even able to read ancient simple music tags like "artist", "album" etc., I wouldn't held my hopes high for parsing & composing video-data.

    Once retrieved, I also doubt whether the Zidoo team can interpret this info properly. Given that all the firmware updates introduced new issues or re-introduced previously solved ones, makes me wonder if they really know what they're doing.
    Feels like too much technical floundering and clutching at straws, without looking over their shoulder. And absolutely having no clue whatsoever about media-ergonomics, IMHO.
    Or maybe they have lack of time to do a proper job, being busy with the launch of their new machines instead...
  7. Bello78

    Bello78 New Member

    I cannot comment on the code and delivery quality of Zidoo team. I don’t know neither their wow, nor their pressure and their priorities.
    And I don’t have enough experience with their devices too, but for now and for my usage, I’m globally satisfied. ;)

    So I will just let this challenge opened.. wait and see ;-)
  8. Temearoo

    Temearoo Active Member

    On a french forum we were talking about the possibility to get a PGS position for all the movies (and more for the episodes of a TV show) by default, just like for the brightness. There is no way to implement this in the settings of the player, because of the nature of the PGS subtitles?
  9. Markswift2003

    Markswift2003 Well-Known Member SUPER Administrator Beta test group Contributor

    Global position for PGS subs is problematic since they are images and it very much depends on the size of the image concerned.

    PGS positions are not absolute but an offset value, and sometimes PGS images are large enough to allow for subtitle placement relevant to who's speaking for example so you can see that a global offset is kind of not possible - I'm sure it's possible to code, it just wouldn't work real world in the same way it does for text subs.
  10. Temearoo

    Temearoo Active Member

    Ok, thanks for the explanations. :)
  11. Whitfield

    Whitfield Active Member

    GPS for PGS :)

    Additional to Mark's comment, you'd also have to consider where you don't want default positioning. As an example, subtitles for a lot of 3D video have been carefully positioned during their authoring so they don't interfere with other objects in the video. Defaulting positions obviously breaks that feature.
    I also can imagine adjustable behaviour would have to be implemented in case of black bars.
    What about the (often few) subtitles that have been positioned differently from the rest in order to not be projected on top of burned-in text or other things in the footage.
    Very tricky to cover all these criteria, I'd say.
    Markswift2003 likes this.

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