Re: [dvd::rip] Forced Subtitles

Triffid:
    Patch is attached. Note that it is quite hackish, but would like to see it incorporated. Feel free to do with it what you like. The main drawback is that I only updated the RGB code and left the YUV as is. This forces you to encode using "--use_rgb -k" (very slow encoding) which is probably why no interest has been shown. I have posted this patch to the transcode users mailing list as well, quite some time ago.

    The patch should be applied against transcode 0.6.14. It adds the following options to extsub:

    forced
       - render only forced subtitles, [0]

    zoom
       - scale the subtitles, [1.0x1.0]

    rgb
       - RGB colour to render with, (hex tuple), [ffffff]
          - eg: yellow would be rgb=00c0c0

    Existing options have been changed as follows:

    antialias
       - enhanced from (0=off,1=on) to (0=off,1=before zoom,2=after zoom,3=before and after)
       - (I find a value of 1 works the best, otherwise I see excessive blurring)

    color1, color2
        - these have been changed from an absolute pixel value, to a transparency value, that is
          where 0 would have written black, and 255 written white, 0 now means transparent, and
          255 means opaque wrt the rgb rendering colour. For example, 128 would average the
          original pixel colour with the subtitle colour (50/50). Since color[12] can be antialiased
          (and zoom blurs a bit too), you get nice smooth blending of the subtitle edges against the
          picture.

    vertshift
       - has been changed to be a simple offset from the bottom of the picture. A new minimum
         bounding box is computed for each subtitle frame, which gives consistent positioning, no
         matter where the subtitle happened to be originally positioned. Unfortunately, this will
         necessitate having to experiment to get the new value correct. Sorry.

Examples:
    -J extsub=track=0:vertshift=80:timeshift=0:
        zoom=0.9x0.75:antialias=1:pre=0:
        color1=0:color2=255:ca=2:cb=3:rgb=00c0c0

        - apply the subtitling as a post operation, hence apply a similar aspect ratio scaling (and
           shrink the original text a bit) that was applied to the original picture (for 16:9). Draw
           the subtitles antialiased using a moderately dark yellow.

    -J extsub=track=0:forced=1:vertshift=60:timeshift=0:
        antialias=1:pre=0:color1=255:color2=0:ca=2:cb=3:
        zoom=0.8x0.68:rgb=00d0d0

        - render only forced subtitles, and apply a shrink/aspect ratio correction

    -j -54,0,54,0 -Y 0,0,8,0 -Z 720x408
    -J extsub=track=0:vertshift=80:timeshift=0:
        zoom=0.9x0.75:antialias=1:pre=0:color1=0:color2=255:
        ca=2:cb=3:rgb=00c0c0

        - here is an example where I take advantage of "post" processing the subtitle
          to add padding at the bottom of the picture where I want the subtitle to go
          so that I don't have to overlay on the picture. (For this particular DVD the
          subtitles were too hard to read no matter what colour was used).
        - usually for any 2.35:1 format I will always force padding at the bottom of the
          picture and draw the subtitles there.

CAVEAT:
    None of the will work unless "--use_rgb -k" is given, which may possibly interfere
    with other filters. (Some are YUV only).

                                                                               Allan

Triffid Hunter wrote:

I would be very interested in this patch. If you send it my way, with your permission I'll try and get it added to gentoo's transcode ebuild as an option.. I've no "veto" in that regard, but hopefully am knowledgeable enough to get it done regardless.

have you sent it to the transcode users mailing list?

Allan N. Snider wrote:

This has been requested before. It would be relatively easy to do. The extsub filter actually does parse the forced flag from the subtitle stream, but then just throws it away. If another field were added to the config.sub structure (in subproc.c), that information could be made available to the filter. Then add an option to only render the subtitles that have the forced flag set. I have a patch which does just this (and works), unfortunately, it is intergrated with numerous other changes to extsub I made that people normally don't want, as they introduce quite a few headaches in the encoding process, (such as being forced to encode using rgb instead of yuv). If you are interested in the source patch, and re-building transcode for yourself, drop me a note and I will send it to you.
Allan

James Sager wrote:

I'm not sure if this has been requested before, but can the option to only include subtitles that have been flagged as forced subtitles be added to dvd:rip? I can see this as being extremely useful and definitely something that I would want to see included. This is a great program and I am using it to transcode my dvd's to XviD for use with MythVideo.

Thanks,

Jim

extsub.patch.gz
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