MKV to M4V?

[Yosho]

I can't mux vtt subs in MP4 with current known options available that I currently know of, converting MKV to MP4.

So, I'm curious if I can convert MKV to M4V somehow and keep VTT subs since MKV can mux VTT subs.

[microchip8]

Which tool are you using to remux to mp4?

[Yosho]

Which tool are you using to remux to mp4?

[DDVT Tool]
and
DoVi_Scripts

but also tried ffmpeg commands.
as well as VLC.

I wasn't very familiar with handbrake and whether or not it could keep the DV though.

.vtt as an external subtitle didn't work on my player with mp4 playing, but in the past DV P5 m4v's did have vtt subtitles muxed that work on player.

.ass subtitles display on screen, but they do not play tags like: {\an8}

.srt would not play it, but would just display in text as {\an8}.

Sidenote: In Subtitle Edit I'm seeing the subtitles displayed in black boxes after saving to vtt. So that is a little awkward and unsure if that would translate to boxes being displayed on player with vtt muxed to mp4.

[SeeMoreDigital]

.vtt as an external subtitle didn't work on my player with mp4 playing, but in the past DV P5 m4v's did have vtt subtitles muxed that work on player.What media player are you using?

[Yosho]

What media player are you using?
My TV media player. LG C9.

[tebasuna51]

Seems ffmpeg can't convert that MKV to MP4 with vtt subtitles:

ffmpeg -i x.mkv -c:v copy -c:s copy x.mp4
[matroska,webm @ 000001f0647602c0] Unknown/unsupported AVCodecID S_TEXT/WEBVTT.
[matroska,webm @ 000001f0647602c0] Could not find codec parameters for stream 1 (Subtitle: none): unknown codec
Input #0, matroska,webm, from 'x.mkv':
Stream #0:0(eng): Video: h264 (High), yuv420p(progressive), 1280x720 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 1k tbn (default)
Stream #0:1: Subtitle: none (default)
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Stream #0:1 -> #0:1 (copy)
[mp4 @ 000001f0666de9c0] Could not find tag for codec none in stream #1, codec not currently supported in container

But if you extract previously the x.vtt file you can use MP4Box to add it:

ffmpeg -i x.mkv -c:v copy x.mp4
mp4box -add x.vtt x.mp4

That x.mp4 is played with subtitles with VLC but not with MPC-BE/MC, but that players accept x.vtt like external subtitles.

[SeeMoreDigital]

My TV media player. LG C9.
As far as I'm aware, the LG C9's media player app supports .srt text based subtitles without styles...

[Yosho]

As far as I'm aware, the LG C9's media player app supports .srt text based subtitles without styles...

That is the case unfortunately..

I am trying to find a subtitle format that works with the player either internally or externally that displays styles. Even better if I could find a way to keep .pgs styles like SubExtractor does, but unfortunately it has a terrible ocr dictionary and everything came out messed up, other than the position and styles.

So far m4v with vtt subs like you would find on streaming service servers, do work, and do display styles but not external vtt with mp4 or mkv. But, unfortunately the muxer was Tencent which is likely difficult to come by likely being proprietary.

I'm going to try what tebasuna51 suggested though and see if that would work by chance.

Edit: It did not work like I wanted it to, but it did display lines that have no stylized text.
Any chance there's freeware mkv to m4v software I could try that could remux it into something similar to the original stream I wonder?

[tebasuna51]

You can see the players with subtitle support here (https://en.wikipedia.org/wiki/Comparison_of_video_player_software#Subtitle_ability)

But not all options can be supported, for instance tags like {\an8} in srt are unofficial (https://en.wikipedia.org/wiki/SubRip)and can be supported or not.

And not all options of vtt (https://www.w3.org/TR/webvtt1/) can be supported for players.

[SeeMoreDigital]

As far as I'm aware, the LG C9's media player app supports .srt text based subtitles without styles...I've just played some subtitle test files with my 2016 LG TV...

With regard to 'text based' subtitles placed within the .mkv container. ASS, SSA and SRT are supported, without styles.
With regard to 'graphics based' subtitles placed within the .mkv container. DVD VOBsubs and Blu-rat PGS subs are not recognised.

With regard to 'text based' subtitles placed within the .mp4 container. TTXT is supported, without styles.
With regard to 'graphics based' subtitles placed within the .mp4 container. DVD VOBsubs are supported but can be erratic.

I haven't tested multiple subtitles streams placed within either container types or external subtitles...

[ProWo]

Seems ffmpeg can't convert that MKV to MP4 with vtt subtitles:

ffmpeg -i x.mkv -c:v copy -c:s copy x.mp4
[matroska,webm @ 000001f0647602c0] Unknown/unsupported AVCodecID S_TEXT/WEBVTT.
[matroska,webm @ 000001f0647602c0] Could not find codec parameters for stream 1 (Subtitle: none): unknown codec
Input #0, matroska,webm, from 'x.mkv':
Stream #0:0(eng): Video: h264 (High), yuv420p(progressive), 1280x720 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 1k tbn (default)
Stream #0:1: Subtitle: none (default)
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Stream #0:1 -> #0:1 (copy)
[mp4 @ 000001f0666de9c0] Could not find tag for codec none in stream #1, codec not currently supported in container.
ffmpeg -i x.mkv -c:v copy -c:s mov_text x.mp4
(assuming one vtt sub only)

[tebasuna51]

Thanks ProWo.

BTW I can't found the mov_text parameter in ffmpeg docs.