How to keep subtitle text from looking ragged in final disc image???!!

[wildgeese]

Hello all,

I hope this is a pretty basic question-

I've been playing around with ffmpegx and subtitles.... If I am playing an avi movie in VLC or movie player and I download an srt subtitle file, I love how the subtitles appear at the bottom of the screen: the font is very smooth. It looks like plain white arial text on a sort of misty, smooth black cloud, which interferes with neither the text nor the movie.

In the screenshot image below, you can see how the appearance of the three text formats line up.

The first image, the one on top, is how a particular selection of text looks in VLC running an srt file for the subtitles. The second image, the one in the middle, is how the text looks in ffmpegx's preview of the movie, and the preview is run using mplayes.

The third and bottom image is the problem. See how the letters are ragged and the black background of the letters is no longer smooth? (Yes, the text is smaller, but that is not the problem, it looks just as bad, just as ragged in a larger size.) This is how the text looks after ffmpegx creates a disc image of the movie, with the subtitle imbedded in the img file.

SO you can see the difference, right? I have been playing around with this since Christmas and I can't figure it out. How do I get the appearance of the text to remain the same in the final img file with ffmpegx??

If you can answer this, THANK YOU!

[url=https://forum.videohelp.com/images/guides/p1941853/picture%204.png]picture%204.png[/url

[Case]

I think I can explain it, but it won't do you much good: there isn't much you can do to improve it.

The issue is that your subtitle text is converted from a smooth font rendering *at monitor resolution* to a bitmap image at *movie resolution*. This becomes quite visible because most movie playback is not at 100%, but at full screen (200% or more), when the jaggies in high-contrast-areas (such as non-moving white letter-shapes) show more.

It is perhaps a bit easier on the eyes with a large font or a bold font, as the raggedness is then a relative smaller percentage of the overall letter shape.

[jagabo]

The last subtitle image was resized with a nearest neighbor (aka point) resizing filter. See if there is an option anywhere in your process that lets you select a different resizing filter. Look for bilinear, bicubic, etc.

[wildgeese]

Hey, Case and jagabo,

Thanks for your help!

I can change the font to a bold font that looks good and see if that helps, so that is definitely a tip worth trying, Case!

As for the resizing filter, I did find some of the keywords that you mentioned, jagabo, but not where I was expecting them so I'm not sure what they'll do. Here is a screenshot of where they appear in my version of ffmpegx, is that what you meant? And if so, does it matter which one to select or shall I just go ahead and experiment? (This could take a few days.... 8) )

Thanks again!

picture%202.png

[jagabo]

Those resizing options are in the Divx encoder options. I don't know ffmpegx and I don't know exactly what you're doing but I don't think you would be using the Divx encoder when making a DVD. I'm guessing you are making a regular movie DVD since you speak of a "disc image". If you are making a data DVD with Divx files on it you would be using the Divx settings. In any case, it should be easy to run a test using different settings. It looks like the default is Fast Bilinear. Try Bicubic or Lanczos instead.

[wildgeese]

Hi jagabo,

I am now pretty much thoroughly and utterly confused. It is true that I am guilty of not knowing squat of the technical jargon I should for trying to burn a DVD, but I am certainly using the program ffmpegx, which is specifically the only thing my question pertains to, since I'm not ready to invest in anything else yet....

I'm not sure why you would make a DVD with divx files on it, don't those need to be Audio and Video ts files? So does this mean I can not use the settings? If so, thanks anyways for trying!

As far as the experimenting being easy, in terms of pushing a few buttons and waiting yes it's easy; but the actual encoding generally takes many hours, and hogs CPU so I can't do much on my computer in the meanwhile. And for huge files it takes even longer: right now I've been converting a file with ffmpegx for fifteen hours, and it is only 44% done. So it will take much time and patience before I have the results and I was hoping someone who knew the program better than I might help make it unnecessary for me to test my own patience so much this week!

[tomlee59]

Re: Divx on DVD. If you simply take Divx .avi files (such as those that you are creating) and burn them onto a DVD as you would any other data, the result can be playable by certain ("Divx-certified") standalone players. The appeal, of course, is that no further manipulation of the files is needed. Just burn and play. The drawback is that this only works with Divx-certified players. If your DVD player is not of this type, it won't work. You can still play them back on computers, of course.

As for 15-hour encodes, a much better way is to perform tests on short segments first. This way, you can zero in very quickly on settings that work for you. Once that's done, then you go ahead and let 'er rip on the whole shebang. It's crazy to have to wait a day or more before you find out that you don't like the result. Structure your experiments carefully, and you can get that part out of the way inside of an hour.

Finally, after all that, I recommend using D-Vision3 instead of ffmpegX for this particular task. It has a "smoothing" option for subtitles that will generally do a nice job of rendering subs cleanly. You can obtain similarly good results with ffmpegX, too, but generally after a fair amount of experimentation. D-Vision3 has fewer options (because it's trying to do Divx only), and so it's easier for most folks to get good results without having to work at it.

[jagabo]

As for 15-hour encodes, a much better way is to perform tests on short segments first.

And invest in a few DVD+RW discs that you can use over and over.

[Case]

jagabo is right about the DivX mencoder options. Mencoder allows for five scaling methods as in the image (each one better and slower than the previous one). But mencoder doesn't encode to MPEG-2 for DVD. And the MPEG-2 encoders in ffmpegX have less settings for scaling.

I am now pretty much thoroughly and utterly confused.

The available settings in the Options tab depend on the chosen preset. When encoding for DivX, the options will be different from the options for encoding to DVD.

I'm not sure why you would make a DVD with divx files on it.

Some set top DVD players can handle that kind of disc. ("DivX/MPEG-4 certified/enabled")

the actual encoding generally takes many hours

When testing, consider cutting a small part from the source file. A two minute file will convert fast, so you'll get to see results and form an opinion on the settings used.