Subtitles & AC3 Pass-through

Any chance we can fast track Subtitle support feature? I’ve tried every program out there to do what needs to be done, and this one does it the best. But I just don’t want to re-encode every video after it’s been exported from Shotcut just to add subtitles via another merger soft or multi-plexer. This, so far, is the perfect video editor slash merger tool for me which works with so many formats like AC3 and Lossless .mxf video files. All that is needed to be able to passthrough original AC3 file and Subtitle file to the final render(export) container file. If the dev(s) could make this on the top of their list it would be the best finalize software out there and solve so many problems of re-muxing and re-encoding over and over again.

Thank You!

You could use Elusiens’s WebVfx framework which has a subtitle feature ( If you have a SRT file, the necessary work is very little.

I think the OP doesn’t want to encode the subtitles so they are hard-coded in the video, but have the SRT file as a separate stream in the MP4/MKV container and have Shotcut put them there rather than having to use yet another piece of S/W.

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Yes exactly it. I don’t want them to be hard-coded on the screen. I want them to be embedded in the container. And I would love for the AC3 to be passed-through into the container as well, without being re-encoded. Which would enable a cleaner faster render as well.

That way the user has the option of enabling or disabling them (subtitles) during playback of the video.

I thought that muxers like MKVToolNix didn’t lower the video or audio quality. I thought they just simply placed the video, audio and subtitles into a mkv container. So muxers can lower video quality anyway like encoding would?

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If you’re adding an AC3 to the timeline in Shotcut, it will have to be re-encoded on the way out. There is no pass-through option that I can see. I haven’t tried MKVToolNix yet. Maybe I’ll just use that to embed the audio / subs into the container. Would it work for MP4 container as well?

Thanks for the suggestion.

That’s obvious but you’re asking about adding subtitles and such. An AC3 Pass-through option would only make sense if you wanted to transcode the video but leave the audio alone. But if you’re editing a video then you can’t pass through the audio untouched because the audio has to match the video which means that the audio also has to be re-encoded. Shotcut is an editor not really just a transcoder although you can bring files in just to transcode them. If you’re looking simply to transcode video but leave the audio alone I’d highly suggest Handbrake which has that very function available. If you want to add subtitles to a video file then use MKVToolNix which will produce a matroska container. Also, you can transcode just the video with Shotcut then use MKVToolNix to put together the transcoded video along with the original untouched audio and whatever subtitles you want to add and it will all be in a matroska container. You can also merge files with MKVToolNix but the files that are to be merged must match codecs, fps, bitrates, etc…