To convert AVI to MKV using VLC: Step 1. Under the Media menu in the top left of the program, select Convert/Save. Step 2. Select the Add button on the menu and select the AVI file you want to convert. Step 3. Under output type, simply select MKV, then click Convert, and your AVI-to-MKV conversion will begin. When I use VLC to play the dvd, I can select the subtitles I want (English, Spanish, etc.) without an issue. But when I go to convert the dvd to an mkv or mp4, I choose that same subtitle option and convert/save, but the subtitles are not available in the final converted file. I've checked Preferences / subtitles to make sure that they're not Select the empty “Use a subtitle file” checkbox and click browse to load the subtitle file for the video on VLC. Depending on your device, you might see a “Convert/Save” or “Stream” button next to “Cancel.” Ensure you select “Convert” or “Convert/Save.” Step 2. Run " VideoSubFinderWXW.exe ", click on " File " and select " Open Video (OpenCV) " to import the video file embedded with hardsubs. As an aside, this program supports major video formats, however, if your video file type is not supported, try to convert it with some free video converter programs. Step 3. Part 1. Convert MKV to MP4 with VLC. ① Download and open VLC media player; click at the top-left [ Media] > [ Convert/Save ]. ② In the following screen, click [ Add] to select the target MKV video; then click on the [ Convert/Save] button at the bottom corner of the interface to proceed. ③ In the opening screen, click the [ Profile] from MKV subtitles aren't merged into the video; they are plain text rendered on video during playback. Because they are already distinct, MkvExtract can extract these to a separate file. Your converted file didn't have real subtitles, but only merged ones, so there was nothing to extract. Share. Improve this answer. Batch convert is a powerful tool that can convert between 300 different subtitle formats with a lot of options. Many formats can also be read from mkv/mp4/ts/m2ts files. Some of the batch convert options have their own settings, e.g. "Merge short lines". To re-encode or remux in VLC, you select the Convert/Save tool in VLC and load the source video file. In the main conversion settings dialog, you can click on the Tool icon. This will open another dialog with 4 tabs: "Encapsulation", "Video codec", "Audio codec" and "Subtitles". The first tab simply sets the container (aka. file) format you want. I want to remux a mkv file into mp4. I used the following command. ffmpeg -i "input.mkv" -c:v copy -c:a copy -map 0:0 -map 0:1 -map 0:2 -map 0:3 -c:s mov_text "output.mp4" Problem: The subtitles in the output.mp4 file are way too small. Also, the subtitles of the mp4 file are unaffected when I try to make them bigger from vlc preferences. MP4 file ignores subtitle settings in VLC. When playing an MKV movie (h264/aac) with a separate .SRT file, VLC lets me control the looks of subtitles perfectly from the menu. However, after losslessly converting the MKV/SRT to MP4 with built-in subtitles ("mov_text"), the subtitles are displayed as a small Arial (?) font, and VLC settings have UAR4DWc.