FFplay video player: subtitles are always invisible

[d9k]

Checklist

• I am reporting a bug in the Onion OS - Any issues with the closed source frontend (MainUI), or RetroArch or any of the cores should be directed to their respective repositories
• I have reviewed the Onion Docs and did not find the answer
• I have searched the existing (open and closed) issues to ensure I do not log a duplicate

Onions OS Version

v4.2.3

Miyoo Firmware Version

202306282128

Provide a clear and concise description of the issue

Seems FFplay in OnionOS can't display any text at all (for example current timing when jumping forward/backward).

It's sad that we have to waste time and electric energy to add hardcode subtitles to the video. Also quality of the resulting video becomes worse.

Steps to Reproduce

Start FFplay (Apps -> Video Player. Try to open any mp4 video (both embedded subtitles and external *.srt with the same name as video). Try to press R2 button to cycle through subtitles as documentation on https://onionui.github.io/docs/apps/video-player says. No subtitles would be displayed no matter what.

Provide any additional context or information that may help us investigate your issue

The bug with subtitles display is unsolved for years: see numerous discussions on https://www.reddit.com/r/MiyooMini/search/?q=subtitles&type=posts&sort=new

I love Miyoo Mini Plus and OnionOS. I was in hope to watch 80-s and 90-s 4:3 anime on Miyoo Mini with original japanese voice acting but conversion process to bake subtitles and lose quality is highly disappointing. Also that would be nice to disable subtitles sometimes and rewatch some intense moments without subtitles.

[ThatStargirl]

Subtitles would be awesome to have!

I think, based on a previous issue #1699 (comment) modifications to FFplay are more a feature request than a bug. That said, the wiki should be updated to indicate the lack of subtitle support. Ironically, from FFplay's error logs, the subtitle keybind does work—FFplay just doesn't recognise the subtitle tracks themselves.

As far as I can tell from playing around with the version of FFplay included in OnionOS, it looks like the it was compiled without subtitle support; specifically it lacks the "subtitle" filter. Enabling subtitle support should be a matter of recompiling FFplay with --enable-libass https://www.ffmpeg.org/ffplay-all.html#subtitles, which in theory might not be too painful to do.

For anyone wanting to tackle this and wanting a place to start: it turns out, this port wasn't actually maintained by the OnionOS team but another project that's gone stale: https://github.com/bobotrax/ffplay_Miyoo . There's unfortunately no documentation explaining how that project's version of FFplay was compiled and configured, but it is based on steward-fu's compilation instructions which you can find here: https://steward-fu.github.io/website/handheld/miyoo_mini_parasyte_build_ffplay.htm

Steps to get this working should then be:

1. Get compilation of FFplayer for the miyoo mini working via steward-fu's instructions
2. Reimplement bobotrax's improvements
3. Add the --enable-libass flag and get that working
4. Modify Video Player's launch.sh to load any subtitle files when running the new version of FFplay (if necessary).

[fengfrw]

By default, mini supports embedded subtitles and dual audio tracks. The link is a test clip (in Chinese).
https://mega.nz/file/vN5FBQ6R#fAegt3DofI47vWVY76Vxrah5u-SMiyI2FqYHt6JbZYI

[d9k]

By default, mini supports embedded subtitles and dual audio tracks. The link is a test clip (in Chinese). https://mega.nz/file/vN5FBQ6R#fAegt3DofI47vWVY76Vxrah5u-SMiyI2FqYHt6JbZYI

That's very strange. Chinese subtitle works, but when I press R2 button, subtitles disappear and I can't turn them on back again.

[d9k]

@ThatStargirl, thanks, very motivational tutorial! Maybe I'll try to recompile FFplay at some weekend in the future.

[d9k]

@fengfrw, thanks!

By default, mini supports embedded subtitles and dual audio tracks. The link is a test clip (in Chinese). https://mega.nz/file/vN5FBQ6R#fAegt3DofI47vWVY76Vxrah5u-SMiyI2FqYHt6JbZYI

>ffmpeg -i 
  Stream #0:3(chi): Subtitle: dvd_subtitle (dvdsub), 720x576 (default)
      Metadata:
        title           : 简汉字幕
        DURATION        : 00:03:16.200000000
  Stream #0:4(chi): Subtitle: dvd_subtitle (dvdsub), 720x576
      Metadata:
        title           : 繁汉字幕
        DURATION        : 00:03:16.200000000

Testing my file:

  Stream #0:2[0x3](eng): Subtitle: mov_text (tx3g / 0x67337874), 0 kb/s (default)
      Metadata:
        handler_name    : English

Seems FFplay for Miyoo Mini supports first track in dvdsub format only.
I'll try to learn how to convert .srt to dvdsub and remux into existing file without video re-encoding.

Do you have video clips with working subtitles in other formats to check?

[fengfrw]

The mini playback is not stable. The sound of this test file is also a two-track Chinese and English language. The subtitles are traditional and simplified Chinese (sub-graphic format). If FFplay can support ass and srt format (embedded or plug-in) subtitles, it will be perfect.

[fengfrw]

https://mega.nz/file/WNAAkJhC#Juu4syRUxrEaKI0jY7gBIulT6zI-HhLZ-OZP_7MXrko
This is a video embedded with ASS subtitles. Mini cannot play the subtitles (potplayer can view subtitles on PC).

[d9k]

I'll try to learn how to convert .srt to dvdsub and remux into existing file without video re-encoding.

❗️Solution to add working subtitles for Miyoo Mini FFplay on Linux:

1. Download srt2vob_0.7 at https://code.google.com/archive/p/srt2vob/downloads
2. Run srt2vob_0.7. Follow errors, install missing dependencies.
3. Let's say you have

input.srt
input.mp4

files. Run:

srt2vob_0.7 input.mp4 input

Last argument is srt filename WITHOUT extension.

srt2vob_0.7 will produse input.sub file.

4. Run

ffmpeg -i input.mp4 -i input.sub -c:v copy -c:a copy -c:s dvdsub dvd-hard-subs.mp4

5. Check that subtitles were embedded:

ffmpeg -i dvd-hard-subs.mp4
  Stream #0:0[0x1](und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt709, progressive), 632x480 [SAR 1:1 DAR 79:60], 278 kb/s, 23.98 fps, 23.98 tbr, 24k tbn (default)
      Metadata:
        handler_name    : ISO Media file produced by Google Inc.
        vendor_id       : [0][0][0][0]
  Stream #0:1[0x2](und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 127 kb/s (default)
      Metadata:
        handler_name    : ISO Media file produced by Google Inc.
        vendor_id       : [0][0][0][0]
  Stream #0:2[0x3](und): Subtitle: dvd_subtitle (dvdsub) (mp4s / 0x7334706D), 720x480, 7 kb/s (default)
      Metadata:
        handler_name    : SubtitleHandler

6. Test file on your Miyoo Mini

Theory

• best subtitle format? | /r/PleX
  • VobSub (IDX/SUB) are bitmap subtitles from DVDs. They typically use two colors, often yellow and black, to draw text using a raster font.

For Windows

Try to google for srt to vobsub, something like

• https://www.videohelp.com/software/SubtitleCreator
• https://github.com/YohanSandun/SubRenderer

[fengfrw]

It seems that the simple point is to convert it into a sub subtitle embedded video file.

[ThatStargirl]

Really awesome to see the rapid progress! 😊

https://mega.nz/file/WNAAkJhC#Juu4syRUxrEaKI0jY7gBIulT6zI-HhLZ-OZP_7MXrko This is a video embedded with ASS subtitles. Mini cannot play the subtitles (potplayer can view subtitles on PC).

@fengfrw you're amazing, thank you! 😁 This test file is super helpful, and made me realise my test file actually didn't have embedded subtitles like I thought—though I was mostly trying with external subtitle files.

That's very strange. Chinese subtitle works, but when I press R2 button, subtitles disappear and I can't turn them on back again.

@d9k huh, I've found the same, it seems if I skip back in the video (left d-pad) the subtitles reappear. This also solves the fast-forwarding that arises from switching audio tracks as described in #1699

❗️Solution to add working subtitles for Miyoo Mini FFplay on Linux:

Fab that you've put together a solution so quickly! I'll give this a try when I get a chance 😊

As nice as it'll be to not need to pre-process files, it occurs to me that a desktop tool for preparing videos for the Miyoo Mini might be desirable anyway—something we can throw (say) a 4k movie at and get a much smaller 640 x 480 video out with the bonus of compatible subtitles. SD cards only have so much space after all.

[d9k]

@ThatStargirl,

it occurs to me that a desktop tool for preparing videos for the Miyoo Mini might be desirable anyway—something we can throw (say) a 4k movie at and get a much smaller 640 x 480 video out with the bonus of compatible subtitles.

That's a cool idea to have something for videos like Calibre do it for books ☺️ With ability to select several videos in GUI, press "sync" and them will convert and upload by wi-fi to Miyoo Mini Plus.

More on Calibre: In Calibre you can add pdf or txt books files to library. In device settings you can set desired format (for example, epub) and conversion settings (for example, force unicode codepage). Then select files and sync to the device with one button.

Update: Found that there was Media File Importer Calibre GUI plugin development. Don't have time to check it yet.

[d9k]

@ThatStargirl,

it seems if I skip back in the video (left d-pad) the subtitles reappear

Thanks! That would be great to address all the subtitles using quirks in https://onionui.github.io/docs/apps/video-player. But windows-using volunteer needed to extend my guide.