Explanation of the new Frame Rate Matching feature on the Amazon Fire TV and how it works

Software update version 6.2.5.3 to the Amazon Fire TV has added the ability to configure the media player so that it adjusts your TVs refresh rate to match the frame rate of the video content being played. This is a feature that home theater enthusiasts have been wanting for a long time because it eliminates video judder and results in a perfectly smooth one-to-one correlation between the frames of a video and the frames being shown on the TV.

Before getting into how this new Fire TV feature works, lets briefly discuss why it exists in the first place. By default, the Fire TV, as with most media players, sets your TV to a refresh rate of 59.94 Hz. This means that the image being displayed by the Fire TV is updating about 60 times per second. The higher the refresh rate, the smoother moving objects will appear. This allows the animations and movements seen when navigating around the Fire TV user interface or inside an app to appear crisp and responsive.

Most movies and TV shows are recorded at 23.976 frames per second (fps). Why such an odd frame rate is used is not important for this discussion, but it’s the source of the issues that the frame rate matching feature fixes. Since, by default, the Fire TV is updating the TV image 59.94 times per second, it needs to figure out how to display the 23.976 frames per second of most videos within the 59.94 refresh rate. If a 59.94 fps video was being played, it would simply display one frame every time it updated the TV image. But since 23.976 does not divide evenly into 59.94, the Fire TV must show some frames more often than other frames.

When playing a 23.976 fps video on a TV set to a refresh rate of 59.94 Hz, which was the only option prior to the new frame rate matching feature, the Fire TV must constantly switch between showing a frame 3 times and then showing the next frame 2 times. This results in something called video judder, which makes motion and camera pans in videos appear choppy because you are literally seeing half of the frames more often than the other half.

The solution to eliminating video judder is to simply display every frame in a video only once. The way to achieve this is to set the TV’s refresh rate to the same value as the videos frame rate. If a 23.976 fps video is being played, then the TV should be set to 23.976 Hz so that the image on the TV only updates once per video frame.

This is exactly what the new frame rate matching feature of the Amazon Fire TV does. When enabled, it will change your TVs refresh rate to exactly match every video you start to play. If the video you begin playing is shot at 59.94 fps, then the TV does not need to be updated because that is the default frame rate of the Fire TV user interface. But when you play a video with any other frame rate, the Fire TV will adjust your TV’s refresh rate just before the video begins to play when you have frame rate matching enabled.

The new frame rate matching option is currently only available on the 3rd generation Fire TV (Pendant). It will very likely be added to the Amazon Fire TV Cube in a future update, but it is unknown at this time if other Fire TV, Fire TV Stick, or Fire TV Edition television models will also gain this feature. To enable the new feature, change the option under Settings > Display & Sound > Display > Match Original Frame Rate to ON. In order to turn on the feature, you must have your Fire TV’s Video Resolution setting set to Auto.

For the frame rate matching feature to work, the app used to play the video must support it. At this time, all videos through Amazon Prime Video will correctly take advantage of this new feature, but most apps, such as Netflix, have not yet been updated to use the feature. With the frame rate matching feature enabled, videos played in unsupported apps will simply play at a refresh rate of 59.94 Hz, just as they have always played. There’s no need to toggle the feature off when using apps that don’t support the feature. The only other apps that currently support this feature are the media player apps MrMC, Kodi, and Plex.

To use frame rate matching for Amazon Prime Video content, simply enable the feature under settings and play any video as usual. Immediately after pressing play on Amazon content, the Fire TV will display the text “Adjusting Video Frame Rate…” for a split second as it changes your TV’s refresh rate to match the frame rate of the video being played. This message does not appear within 3rd-party apps that support refresh rate matching. Once the video ends, the TV will switch back to a refresh rate of 59.94 Hz just before returning to the user interface.

MrMC Setting

Kodi Setting

Plex Setting

In addition to enabling the refresh rate matching feature in the Fire TV’s settings, you may also need to enable the option inside the app you use to play video. In MrMC, you’ll need to go into Settings > Video > Playback and set the “Adjust display refresh rate” option. You’ll need to change the settings mode from “Basic” to “Advanced” or “Expert” for this option to appear. In Kodi, the setting is under Settings > Player Settings > Videos. Likewise, Kodi’s settings mode will need to be changed from “Basic” to “Standard” or higher to see the option. In Plex, you’ll need to change the “Refresh Rate Switching” option to “On” under Settings > Advanced.

The biggest downside to this new feature is that most TVs will display a black screen for a few seconds every time the refresh rate is updated. The amount of time it takes for the TV to change to a new refresh rate is completely dependent on the TV and has nothing to do with the Fire TV. Some TVs feature dynamic refresh rates that can change on-the-fly instantaneously without displaying a black screen, but most will take a second or two to switch. Since this will happen every time a video starts and again when it stops, some people don’t find the frame rate matching feature worth the inconvenience of waiting for the TV to adjust. A compromise could be to leave the feature off for regular day-to-day viewing, but flip it on for movie night or highly anticipated movies and shows.

In my testing, the Fire TV correctly switched the TV to a refresh rate of 23.976Hz, 24Hz, 25Hz, 29.97Hz, 30Hz, 50Hz, 59.94Hz, and 60Hz when a video of each matching frame rate was played. I did verify that it does correctly use fractional refresh rates. This means that, for example, it does not use 24Hz for a 23.976fps video. A 23.976fps video uses a 23.976Hz refresh rate. Refresh rate switching occurs both in 4K, 1080p, and lower resolutions.

The only oddity I encountered is that the Fire TV sometimes set the TV to a refresh rate that was double the video frame rate, instead of using the exact refresh rate. This resulted in a 25fps file using a 50Hz refresh rate, a 29.97fps file using 59.94Hz, and a 30fps file using 60Hz. This is fine because it means each frame is displayed exactly twice and achieves the exact same effect as using an exactly matching frame rate. Remember, unwanted video judder occurs when the frames cannot be evenly divided into the refresh rate, so a TV refresh rate that is double the frame rate of the video does not have a negative effect. Interestingly, this doubling behavior did not always occur. For example, playing the first episode of the second season of The Grand Tour, which is a 25fps video because it was shot in the UK, used a 25Hz refresh rate, but playing a 25fps video in MrMC used a 50Hz refresh rate, so it might be dependent on the app being used.

Update

MrMC has informed me that they deliberately use a refresh rate that is double the video frame rate, whenever possible, in order to preserve UI smoothness. Kodi and Plex likely adopted MrMC’s open source code, since MrMC was the first to support frame rate matching. This means that 25fps, 29.97fps, and 30fps videos will use a 50Hz, 59.94Hz, and 60Hz refresh rate, respectively, in all three apps when possible. Additionally, some TVs struggle, and even flicker slightly, when set to low refresh rates, so doubling the frame rate when it has no negative consequences alleviates those issues as well.

If you want to verify that the correct refresh rates are being used, you should enable the “System X-Ray” setting and “Advanced Options” setting in the Fire TV’s hidden Developer Tools Menu. The menu can be opened by holding the SELECT and DOWN button for 5 seconds and then pressing the MENU button on the remote. The System X-Ray setting will display a bar across the top of your screen. The number after the 2160p/1080p/720p resolution value is the current refresh rate of your TV. While in the Fire TV interface it will likely be 59.94 and will change once a video begins playing and your TV’s refresh rate is updated. Note that the value displayed is truncated to 2 decimal places, so when the refresh rate is set to 23.976, it will be listed as 23.97 in the System X-Ray bar.

Enabling the “Advanced Options” setting in the Developer Tools Menu will display a box on the right side of the screen that contains information about the video currently being played. The most important value for this scenario is the one labeled “Frame Rate” under the “VIDEO” section. This value is like a running average of the actual playback frame rate, so it might not exactly match the frame rate you’re expecting at first, but it should eventually level off to list the video’s actual frame rate. Sample files to use for testing various frame rates can be found here.

Additionally, most TVs have a way of displaying information about the current resolution settings of the TV. This sometimes includes information about the current refresh rate. That can also help you determine if your Fire TV is correctly switching and using the refresh rates you’re expecting. However, be aware that some TVs will round decimal refresh rate values to whole numbers, so even though the Fire TV might actually be using a refresh rate of 23.976Hz, the TV might incorrectly display it as 24Hz.

Lastly, the Fire TV will only switch your TV to refresh rates that it detects your TV supports, so the full list of refresh rates listed above may not be available to you with your particular TV. Devices like AV Receivers or HDMI switches connected between the Fire TV and your TV could prevent your Fire TV from correctly detecting your TV’s refresh rate capabilities. If you suspect this is happening, try connecting your Fire TV directly to your TV’s HDMI input.

ShareTweetShare+1

48 comments
  1. Masterblaster says:

    Wow Elias that was a great explaination and awesome research too.

  2. Rob says:

    Nice explanation and thanks for putting this together.

  3. James P Updike says:

    I really want this on my Fire Tv 2…

    • AFTVnews says:

      Going by what has happened in the past, Amazon tends to focus a bunch of updates on the newer models at first but then eventually syncs up all devices. When the Fire TV 2 came out, the Fire TV 1 and Stick were mostly ignored for several months and then all models received an update simultaneously that gave all features to all devices. I’m hopeful the same thing will happen again, but we’ll have to wait and see. The sync up happened when all models were updated to Fire OS 5. Since we still don’t know if all models will get Fire OS 6, it’s tough to say if features will be synced the same way as they were in the past.

      • ermic says:

        I still hate the so called Fire TV 3 and keep my FTV2 box until they make a real successor, instead of just a Fire TV stick with slightly upgraded specs. I know many people that will agree with me. So Amazon has a choice to make, update the FTV2 or release an actual FTV3. If they just keep this new feature to the new stick they call FTV3 I’ll just change the manufacturer of my streamer. I also know many people that will agree with me on this too. I wonder if their HQ actually knows how frustrated long time users start to become. The FTV lineup was great 4 years ago, but alternatives pop up everyday while they disimprove the FTV line, e. g. the disappearancwle of clear “included with your prime subscription” markings or the introduction of trailers and ad banners when using a FTV. If they really don’t feel the need to update formerly released models I’ll just take my business elsewhere. And I am sure: I am not alone with this sentiment.

        • hdmkv says:

          Real successor = nVidia Shield TV. I have a FTV pendant and cube for secondary viewing needs, and gave up waiting for a powerful FTV box.

          Amazon doesn’t seem focused on better specs, rather cheaper devices. We also never got a true successor on the tablet side to HDX.

          • Mike says:

            I know what you mean. I like the FireTV remote and interface better, but the quality of the picture on the nVidia Shield TV is really nice. When I want to watch regular TV or replays of old shows then FireTV is OK, but for movie night, the Shield is the way to go.

            (I know this is a tardy comment, but … )

  4. infinity says:

    Well, that’s the point: “if” they Update all Devices to FireOS 6.x

    I’m not that hopeful, because FTV1 Stick, FTV1 and FTV2 are mediatek based, thus featuring the same or very similar SOC, hence the codebase (especially kernel) was kind of the same – meaning they had to do the hard work only once.

    With FTV3 and Cube they switched over to amlogic, where the worst (and thanks to amlogic terrible) work on kernel and debugging has been done for almost two years by the community (openelec/libreelec, kodi) to finally sort out most ridiculous issues. Lets see whether amazon is committed to do this hard work for old and probably buggy mediatek.

  5. HisMajesty says:

    Awesome explanation. love this site

  6. Paul w says:

    Thanks for the article.

  7. hdmkv says:

    The doubling of frame rate for example from 25 to 50 is acceptable.

    • AFTVnews says:

      I’d say doubling is actually preferred since some TVs struggle with lower frame rates and the higher rate keeps UI elements moving smoothly. I mostly pointed it out in the article because the doubling seemed inconsistent, meaning it sometimes doubled but other times didn’t.

      • AFTVnews says:

        I just spoke with MrMC. They deliberately double the frame rate to keep the UI smooth. I’ve added an update to the article.

        • hdmkv says:

          This updates just made me keep my AFTV3 pendant & cube. Was thinking of eBay’ing both. I have a Shield TV, and funny thing is I was getting 4K/23.976 out of it for Amazon’s own 4K HDR content (like ‘Bosch’) and not FTV. Glad Amazon finally addressed the framerate issue.

  8. Rob says:

    Since Amazon is reliant on app developers to support frame rate switching I wonder if they will be inclined to update their own app on the Nvidia Shield? I can only hope…

  9. HeffeD says:

    This feature seems a bit buggy. I’ve enabled it on my device, but it keeps changing my display resolution from “Auto”, to 1080p, 60Hz. Is that normal? Do you know of some Prime content that switches so I can verify if it’s working or not?

    • AFTVnews says:

      I didn’t experience the resolution changing on its own.

      The Grand Tour Season 1 Episode 1 is 23.976 fps and Season 2 Episode 1 is 25 fps.

    • tampa8 says:

      Unless I’m not understanding, isn’t that exactly what it is supposed to do? It is reporting the settings you are watching.

      • HeffeD says:

        No, it’s the menu setting itself that keeps changing. I don’t think that’s what is supposed to be happening.

        It is adjusting the framerate though, but I don’t think it’s working properly. I do see the Adjusting Video Frame Rate message when watching The Grand Tour. However, with the audio set to Dolby Digital Plus, (over HDMI) the audio and video are quite a bit out of sync. (maybe half a second?) Turning off Match Original Framerate fixes the issue. I did also try using Dolby Digital, but the results are the same as Dolby Digital Plus.

  10. beq says:

    I’m always impressed by the thorough and insightful articles on this site!

    If only we could get this quality reporting for other platforms, heh.

  11. Paulch3n says:

    You forgot, that Amazon prime does not play right 25 fps files. Mrmc does. I tried Gray’s anatomy in German, which is 25 fps in video stream, but 24 in display. So it looks like Amazon just play 23.97 and 24 right. But some 25 will play like 24 and get judder.

    • King Nothing says:

      I got the update yesterday. And for me Grey’s Anatomy actually switches to 25Hz. The problem is that with 25Hz I only have picture but no sound. So it seems my TV reports that it supports 25Hz, but obviously it doesn’t fully do. All other modes I tested work with sound.

      So in your case I guess your setup doesn’t report 25Hz as supported mode, so the Fire TV switches to the closest mode available (24Hz) which isn’t really the way it should behave. In those cases it should favor the modes that are the double of the native framerate (50Hz in this case) just like Kodi or MrMc do.

      But beside all of this I have to say that I’m very disappointed with the update. The default 59,94Hz mode with pulldown was totally fine and almost perfectly smooth before the update. And now it looks kind of jerky and almost like it constantly flickers. And even if the Prime Video app switches to native framerates, there is some occasional stuttering which almost looks like framedrops. Although the system overlay doesn’t show dropped frames. It maybe only my device or the combination with my setup but for me the update that was supposed to eliminate all stutter introduced even more.

      • Paulch3n says:

        Okay, not for me. Fire tv sticks in Marantz avr, mit mrmc fire tv change every fps rate. Amazon prime video just 23,97 and 24 and 24 for 25 at for example Grey’s anatomy. While mrmc plays everything fine, there must be the problem in the prime video app

  12. Marc says:

    This update seems to have added extra options to the list of resolutions and refresh rates that cycle when you press reverse and up. I’m sure it didn’t have 2160p 24hz on there before. This is a pain to do but makes a load of Netflix content a lot smoother.

    • Marc says:

      Just realised Netflix won’t play in 4k when you use this option. Hopefully they update the app so it can switch refresh rate

      • Albert says:

        netflix won’t play in 4k when you similarly force 2160p 24hz on the Nvidia Shield as well. I have been forced to using the built in Netflix app on my TV for proper 4K frame rate.

        • Albert says:

          Also, on my 2015 M60-C3, only the old Amazon Fire TV with 4K plays Netflix at 24 fps automatically regardless of what setting I choose, the new pendant plays at 60fps and there is no way to force it to 24.

  13. HN says:

    What a great explanation. I can’t wait to see this update on the Firestick 2.

  14. attereb says:

    i just played my first amazon prime video with this enabled last night and noticed my sound was not in sync with the video. has anyone that tried this noticed this yet?

    • HeffeD says:

      Yes, I have the same issue. I’m using Dolby Digital Plus over HDMI. Dolby Digital over HDMI has the same problem. I think the ability to match the native framerate is a step in the right direction, but it’s completely unwatchable for me because the audio being out of sync drives me crazy.

    • Paul w says:

      Mine is out of sync too. I had to turn the feature off and then restart my fire tv. What a load of rubbish.

    • Paulch3n says:

      Did you tried lip sync feature? My fire tv goes over Marantz avr with lip sync enabled. I didn’t feel an out of sync in the video

  15. Keith says:

    I know I’m late to this but figured I’d ask anyway.
    There doesn’t appear to be an option within Plex settings to change the refresh rate.

  16. Aaron says:

    Sorry to be late to the comment party, but a question: I was pretty sure that I have already seen MrMC do this on my older Fire TV box for quite some time now. When I play a video, the TV goes blank for a second then switches rates to match what is being played. I understand other apps besides MrMC (Netflix, Hulu, etc) haven’t had that feature. But I’m 99% certain MrMC has, even without this OS-level update. Or am I mistaken?

    • Paulch3n says:

      Half mistake ;) yes mrmc is capable of switching frame rate on older fire tv (my first gen) but just limited to 24 Hz and not 23.97 I tested first vs 3 gen fire tv mrmc with the same movie and 3gen switch to 23.97 and 1gen zu 24p with droped frames

  17. Wuschel says:

    https://stadt-bremerhaven.de/amazon-fire-tv-fire-os-6-2-5-3-sorgt-fuer-korrekte-bildwiederholrate/#comment-867617

    Here it’s mentioned that there are still some odd examples where Amazon Prime videos are not played correctly with their source framerate. E.g. Grey’s Anatomy where the X-Ray overlay reports a source framerate of 25p whereas the actual framerate chosen by the FireTV is 24p…

  18. FTVSTICKGUY says:

    Attention FTV, Stick Old Gen users

    Please contact Amazon chat/phone to request this feature in our devices.

  19. Albert says:

    On my 2015 M60-C3, only the old Amazon Fire TV with 4K plays Netflix at 24 fps automatically regardless of what setting I choose, the new pendant plays at 60fps and there is no way to force it to 24. I am very upset at this.

  20. Jim says:

    Found a bit of weirdness with this tonight– I was watching Man in the High Castle, which used to play fine in 4K, but with Match Frame Rate enabled, the resolution was switched from 2160/60fps to 1080/24fps.

    I thought that this was an issue with my projector not supporting 24fps at 2160P, but from what I’m reading, that mode is supported. So I’m not clear why I took a resolution hit.

    I’m leaving Match Frame Rate on for now, but might cancel that for Prime Video content if this continues.

  21. Pir8radio says:

    This works great with Emby. Its kind of a better plex.

Leave a Reply

Your email address will not be published. Required fields are marked *

*

Subscribe to AFTVnews!

Get all new articles in your inbox.