It’s really a great pity for people who have many MKV videos! Maybe you have tried to download MKV to Kindle Fire HD tablet for playback directly,but MKV is famous for multiple subtitles and audio tracks, which meanwhile, it's a common HD video format. This format can't be supported well by a lot of tablets due to its complexity, and Kindle Fire HD only can play videos in MP4, 3GP, VP8 format. So it’s necessary to find a professional video convert tool to transcode MKV videos to H.264 for Kindle Fire HD.

I have used Brorsoft MKV to Kindle Fire HD Converter to re-encode MKV files to Kindle Fire HD friendly format .mp4. I love it very must, it is doing exactly what I need it to and better still it is very easy to use. Only used once but that went with zero issue, and this tool also allow me to join several .mkv files to one file as you want. If you get other video files like AVI, WMV, FLV, VOB, TiVo, etc for adding to Fire HD 7" tablet, this video converter also works well.

Guide:Getting MKV videos to play on Kindle Fire HD

1. Run the best Kindle Fire HD Video Converter, and import your source files to it. You can either import source video clips one by one, or load through a folder at a time.

2. Choose Amazon Kindle Fire H.264(*.mp4) as output format for Kindle Fire HD from the Format > Android presets list.

3. Click “Settings” button to adjust video and audio parameters. Here we recommend you to set the video size as 1280*800 for enjoying full screen movies on Kindle Fire HD 7, and choose bitrate as 1500 ~ 2500 is appropriate.
Tip: If you prefer to get a file with much clearer image quality and do not mind generating a relatively large file size, you can change the video bit rate higher to 2,500~4,000. Remember, the higher bit rate, the bigger output file size.

4. Click “Convert” button to start the MKV to Kindle Fire HD(KFHD) conversion at fast speed, especially when you enabling CUDA or AMD APP acceleration.

When the conversion is done, click "Open" button to get the converted MP4 files. Now you are able to transfer MKV movies to Kindle Fire HD 7-inch tablet for playback on the go.

Note: Videos transferred via USB will only be available in the Gallery app. Only videos from the Amazon Video store are shown in the Video library.

Related guides:
Rip and put DVD movies to Kindle Fire HD
Get Kindle Fire HD full reviews and movie playback tips
Transfer videos, pictures, music to Kindle Fire HD from PC
Viewing Blu-ray, DVD movies on Kindle Fire HD
Convert MKV/AVI/FLV/MOV to Kindle Fire HD
Enable WMV movies playable on Amazon Kindle Fire HD
Play XVID/AVI movies on Kindle Fire HD