Description

The nablet HEVC AMA plug-in allows you to link, play and edit HEVC/H.265 video in MP4 or MOV container via AMA in Avid editing products. It supports processing footage in the video sub-sampling formats 4:2:0 and 4:2:2 at 8 and 10 bits. AAC and PCM audio are supported.

The nablet HEVC AMA plug-in reads the time code and interprets most of the important metadata when this is encapsulated in the media. Furthermore, it detects BT.2020, HLG, and other HDR capture gamma formats in HEVC shots so that Media Composer can automatically assign a color transformation that matches the project color space.

Furthermore, with the nablet HEVC AMA plug-in, you can work with XAVC HS proxies.

Evaluation

The downloaded copy of the nablet HEVC AMA plug-in will run in demo mode. A nablet logo will be printed into the decoded images but otherwise, the plug-in is fully functional. Follow the instructions in this user guide to purchase a license key and unlock the plug-in to make the logo disappear.

After the plug-in was unlocked by a license key file, you can continue to use the clips that were previously linked in demo mode. You do not need to re-link them. The logo will disappear after the key has been validated by the plug-in. However, transcodings and video mix-downs have to bere-done since they have been encoded with the logo in the source image.

Requirements

Supported Avid Products

• Avid Media Composer from v8.6 to the latest releases.
• Fixed occasional timeout messages during fast scrubbing.

Supported Operating Systems

Windows

• Windows 11
• Windows 10 64-bit

Mac

• macOS 14 (Sonoma) (Intel, Apple Silicon via Rosetta 2)
• macOS 13 (Ventura) (Intel, Apple Silicon via Rosetta 2
• macOS 12 (Monterey)(Intel, Apple Silicon via Rosetta 2)
• macOS 11 (BigSur) (Intel Mac only)
• macOS 10.15 (Catalina)
• macOS 10.14 (Mojave)

Hardware Requirements

Decoding HEVC is a challenge for a computer system and is most satisfying on modern hardware.

For best performance, on Windows systems, the PC should be equipped with an NVIDIA or AMD GPU or an Intel CPU with the Quick Sync Video feature available, which supports decoding of HEVC footage. An Intel processor with Quick Sync Video starting from the Skylake family is suitable (Skylake fully accelerates 8-bit and partially accelerates 10 bit, later generations fully accelerate 8 and 10-bit). For the capabilities of your external GPU please check the manufacturers' specifications.

Minimum required GPU driver versions:

• NVIDIA - 470.0
• AMD - 20.7.1
• Intel Iris - 26.20.100.8141

Decoding of 4:2:2 footage is currently not supported by any GPU accelerator and is processed by a software decoder which however may benefit from a partial acceleration on some systems.

On Mac systems HEVC decoding is supported through the Apple Video Toolbox API and performance depends on the system hardware configuration:

• macOS 10.13 supports 4:2:0 footage only,
• macOS 10.14 and macOS 10.15 support 4:2:2 as well. For best performance, it is recommended to upgrade to macOS 10.15 or later.

Even if the hardware of your system does not meet the requirements for fluent real-time playback of HEVC, you still have the option to link the clips and then transcode them to an intermediate proxy or DNxHR profile for further processing.

Change Log

• v1.5.1
  • Fix video sample loss or image distortion upon fast scrubbing on macOS.
  • Fix possible decoder hangup on Intel GPU with the latest drivers (v101.5522).
• v1.5.0
  • Extended ISO range for EI processing.
  • Hardware improvements accelerated decoding.
  • Approved for macOS 14, Sonoma.
• v1.4.0
  •  Changed support for embedded LUT in Sony XAVC HS clips to a more user-friendly and
    convenient workflow.
  • Added control to modify the exposure of XAVC HS clips in Source Settings to support the Sony Cine EI workflow.
• v1.3.0
  • Support for embedded LUTs in Sony XAVC HS clips.
• v1.2.8
  • Fixes flipped display of rotated clips
• v1.2.7
  • Add support for XAVC HS clips with 96kHz PCM audio
• v1.2.6
  • Approved for Windows 11 and macOS 12 (Monterey)(Intel, Apple Silicon via Rosetta 2).
  • Performance improvement on scrubbing.
• v1.2.5
  • Added support for multiple AAC multichannel audio tracks.
  • Set shot marks from Sony metadata as markers on the timeline.
  • Improved scrubbing behavior.
• v1.2.2
  • For Sony XAVC HS type proxy clips additional dummy audio tracks are added to match the main recordings number of channels.
  • Updated Sony proxy editing workflow instructions.
  • Improved detection of the supported video track.
• v1.2.1
  • Added support for Sony proxy (sub-stream) workflow.
  • Improved metadata detection and parsing.
• v1.2.0
  • Mac version refactored and approved for macOS 11.0 (Big Sur).
• v1.1.2
  • Fix: Random start timecode could appear on clips that have no timecode.
  • Accept clips with variable framerate (VFR) from smartphones for linking.

Note that VFR clips may be linked and played but longer clips may lose audio synchronization. Transcode longer clips to constant framerate by third-party tools before linking.

Try before you buy

Before you purchase a license key for this product, please evaluate the plug-in in demo mode to verify that it fits your needs. Try whether your system is suitable for a sufficient workflow and make sure that the footage which you need to edit is supported.

If you got HEVC material that is not properly decoded let us know and provide a sample. We will try to support it in the next version of the plug-in.

Note that footage with variable frame rates, as it is recorded by some smartphones, is not yet fully supported. Such clips can be linked and played, but longer clips may lose audio synchronization. Transcodelonger clips to constant framerate by third-party tools.

Installation Procedure

Prerequisites

You cannot install the AMA plug-ins while the editing application background services are running. Make sure you stop the services before installing AMA plug-ins. The stop/start background services icon is on the Media Composer menu bar (Macintosh) or taskbar (Windows). Once you installed the new AMA plug-in, restart the services. See “Starting and StoppingAvid Background Services” in the Media Composer Help.

Install Instructions

Windows

1. Download an archive with the plug-in and extract it to some folder.
2. Run the installation EXE file from the extracted folder to start the installer.
3. Follow the instructions provided by the installer. Read and accept the End-User License.
   If you already own a license key file pass its path when asked.
   If you used a temporary key file that you received for test purposes you can update it now with the key file you purchased.
4. During the installation, any previous version of the nablet HEVC plug-in will be updated.

Mac

1. Download the installer package of the plug-in and unpack it.
2. Run the installation DMG file to mount the image. You should see a folder with the “nablet_HEVC_AMA_Plugin_Setup_Mac” package opens.
3. Launch the PKG file to run the installation.
4. Follow the instructions provided by the Installer application. Read and accept the End-User License. 
   If you already own a license key file pass its path when asked.
   If you used a temporary key file that you received for test purposes you can update it now with the key file you purchased.
5. During the installation, any previous version of the nablet HEVC plug-in will be updated.

Uninstall Instructions

Windows

1. Open Windows Control Panel and launch “Programs and Features”.
2. Select “nablet HEVC plug-in” and then select Uninstall.
3. Select Yes to confirm the removal. Once completed, the plug-in and the license key file are removed.

Mac

1. Locate the directory “Library/ApplicationSupport/Avid/AVX2_plugins/AMA/nablet”.
2. Delete the nablet_MVP_MSP_HEVC.avx file.
3. Delete the license key file 'nablet_HEVC_Plugin_my_name.key'.
4. Empty the Trash to completely remove the files from the system.

Verifying the plug-in Version

After installation, the “nablet HEVC plug-in” is available to Avid Editing products. To confirm whether the plug-in is properly installed and verify the version follow the steps below:

1. In Media Composer's project window, hit the Info button. You should see a list starting with the version and license information for Media Composer.
2. Scroll down to find the AMA Plugin Info.
3.  Confirm that the “nablet HEVC plug-in” is listed and the version matches the version you have installed.

License Activation

As long as the plug-in runs in demo mode a nablet logo is imprinted into the decoded images:

To purchase licenses for the visit the nablet store.

For each license that you purchase, you will receive a key file to unlock the plug-in:

• Shut down Media Composer and the BackgroundServices.
• Run the HEVC AMA plug-in installer again, follow the instructions, and pass the path to the key file when asked. Then continue the installation.
• Restart Media Composer.

Keep a copy of the KEY file in a safe place. You will need it again after the plug-in had been uninstalled. Do not rename or modify the license key file, otherwise, it becomes unusable.

The key must be used on a single computer only. You may also purchase multi-user licenses and site licenses.

Once the license key has been validated by the plug-in, the nablet logo will disappear from the linked clips. Now redo any transcodings, consolidations, and video mixdowns that have been done during the evaluation period and which show the logo. 

Operation Procedure

Linking single or multiple clips

Linking to HEVC files on Media Composer 8.6 and later

1. Select the desired destination bin in the project.
2. From the menu bar, select File->Input->Source Browser.
3. When the Source Browser dialog, make sure that Link is selected, not Import:
4. Navigate to the HECV file(s) to be linked.
5.  Media Composer doesn't assign the plug-in automatically. Select and right-click the desired file(s) and select Link with->nablet HEVC.
6. Hit the Link button on the bottom right to link the files.

Linking to HEVC files on Media Composer 8.5 and earlier

1. Select the desired destination bin in the project. 
2. From the menu bar, select File->AMA Link… (Link to Media… if using Avid MC 8.4).
3. MediaComposer will not assign the plug-in automatically. From the Files of Type drop-down menu select “nablet HEVC (*.mov, *.mp4)”.
4. Select the file(s) to be linked.
5. Hit the Open button on the bottom right.

Linking whole recording media content at once

Some cameras write clips into a specified folder structure on the recording media, where also companion metadata files may be stored. In a typical workflow, you copy the complete contents of each recording media, including all sub-folders and metadata files, into a new parent directory on your local storage. This parent directory's name may contain the shot location, card number, and other information to later easily identify the footage. If the camera manufacturer folder structure is supported by the plug-in, you can now link the whole media contents at once by linking the parent folder.

Linking to an HEVC Volume on Media Composer 8.6 and later

1. Select the desired destination bin in the project.
2. From the menu bar, select File->Input->Source Browser.
3. When in the Source Browser dialog, make sure that Link is selected, not Import.
4. Navigate to the desired volume.
5. Select the parent folder above the volume root folder.
6. Press the Link button on the bottom right. Media Composer will choose the nablet HEVC plug-in automatically.

Linking  to an HEVC Volume on Media Composer 8.5 and earlier

1. Select the desired destination bin in the project.
2. From the menu bar, select File->AMA Link… (Link to Media… if using Avid MC 8.4).
3. Media Composer doesn't assign the plug-in automatically. From the Files of Type drop-down menu select nablet HEVC (Folder).
4. Select the parent folder above the volumes root folder.
5. Press the Open button.

Transcoding

Do not attempt to transcode a linked clip from within Media Composer's Source Browser as offered when you tried to Import instead to Link. Always link the footage as described above. When done navigate to the bin with linked clips, select the desired clips, right-click and select Consolidate/Transcode. In the Consolidate/Transcode dialog select Transcode on the top left. For details about the further settings please refer to the Media Composer manual. Once the transcoding is completed the transcoded file(s) will appear next to the linked source clip(s) in the bin.

Auto Mount

When you insert the recording media into a card reader that is connected to your PC or when you connect your camera to your PC via USB while Media Composer is running, it may detect the volume and automatically link the clips into a new bin. While this procedure seems to be convenient, please keep in mind that the footage remains on the recording media. Once the media is removed or disconnected the footage is marked as offline.

Use this way of linking only when you want to immediately transcode the footage for editing after linking.

Performance problems during linking with Source Browser of Media Composer 8.6 and later

In some cases, the Media Composer Source Browser may be very slow and sometimes behave erratically when you attempt to link single clips rather than a whole volume. If you frequently face issues with the Source Browser, an option is to use the legacy link dialog instead. This dialog is still available under Media Composer 8.6 and later, but it is hidden. To make it available persistently select Tools->Console and in the console command line type

ToggleHideLinkMenus 

and hit Enter. (To hide the dialog again repeat the command). Now proceed to link clips and volumes as described for MediaComposer 8.5.

Source Settings, Color Transformations and Embedded LUTs

In order to view the Source Settings window, you must right-click a clip in a bin and select Source Settings… There are three tabs in this window, Linked Plug-in, Color Encoding, and FrameFlex that affect
the image appearance.

The Color Encoding tab allows you to add and remove LUT tables, which will change the visual look of
the image which can transform the clip's color space to the project color space.

The FrameFlex tab allows you to change the dimension and framing of the image.

The Linked Plug-in tab allows you to change the exposure of the clip. Application of an embedded LUT,
which is explained later, can be enabled here as well.

Note that exposure control is only available for XAVC S Clips shot with Slog3 capture gamma. Initially,
the value for Exposure (EI) that was found in the clips metadata is used. The Exposure can be adjusted
in a range from ISO 80 to ISO 10000 in steps of 1/3 of a stop.

To reset the custom exposure setting to the value at recording time choose Clip Meta Data settings
above. To reset them to generic defaults choose the Default settings above.

Note
On some versions of Media Composer, the first attempt to change a value does not take effect. To
overcome this, toggle a setting one time, e.g. switch between Clip Meta Data and Default and back.
After that, any further changes will take effect.

The image preview on the Linked Plug-in tab shows the image in the format before any Color
Transformation LUTs and Look LUTs have been applied on the Color Encoding tab. Switch to the Color
Encoding tab to view the final effect of your custom settings after the LUTs have been applied and thus
how the image will appear in further processing, or, if the clip is opened in the Source Monitor, use a full-screen display on a secondary monitor to view the final image while you change settings.

Managing Color Adapters

When you link footage whose Capture-Gamma or Transfer-Characteristic does not match the project color space, for example, a clip with Sony S-Log3.Cine into a BT.709 project, a color transformation is needed to correctly display the pictures.
Media Composer ships with a variety of LUTs for color transformations, including those for Sony S-Log color spaces. Automatic insertion of a matching color transformation upon linking can be enabled in the Color Management Settings. They can be reached either via File->Settings->User tab or at the Color Encoding tab in the Source Settings dialog.

Open the Source Settings dialog of the linked clip to see the current color transformation.

If automatic insertion of a color transformation is disabled in the Color Management Settings, or if the clip color space matches the project color space, the Color transformations list will be empty. If color spaces don't match, you can now insert a color transformation manually in two ways:

• Under Color Adapters hit the Auto button which will cause MC to insert the required transformation
  automatically now.
  
• Or select the desired Color Adapter from either the Generic or User installed LUTs type.
  

Look LUTs and custom Color Transformation LUTs

If you have a Look LUT, a LUT that gives the recorded video a creative look, or a custom color space transformation LUT that you want to insert, first you need to install that LUT via the Color Management Settings dialog.

For details please see the Media Composer user manual. A user-installed LUT can be inserted in the same way as manually inserting a color adapter. Select it from the User Installed LUTs Color Adapter type.

Make sure to position a Look LUT before any color transformation. If you added a Look LUT after a color transformation was added automatically or manually, you can easily drag the Look LUT upwards to the top position.

Sony XAVC HS Embedded LUTs

Some Sony XAVC HS clips may carry an embedded LUT. This can be a creative LUT to apply a specific look to the recorded footage or a color transformation LUT for example for conversion from Slog3.Cine to BT.709 or they can even be a combination of both. When an embedded LUT is available you will find the
additional checkbox on the Linked Plug-in tab.

Hover with the mouse over the checkbox to get information about the name of the LUT. To use this
LUT, enable its application with this checkbox. Also for this, on some Media Composer versions, you
may need to toggle the setting once to see the application of the LUT taking effect on the display
window.

You can also check the availability of an embedded LUT in the bin's Monitoring Descriptions column

The name prefix “EMB1” indicates that it is an embedded LUT.

If the LUT is a pure creative LUT, after you enable the application of it the color transformations on the Color Encoding tab can be kept as they are. However, if the LUT contains a color space transformation, the color transformation on the Color Encoding tab must be deleted. Otherwise, you will get a duplicate color transformation which results in a bad image with the wrong colors. Switch to the Color Encoding tab, select the items in the Color transformations list and delete them.

If you know in advance that the footage has an embedded color transformation LUT and that you want
to use it, disable the automatic insertion of color transformation in the Color Management Settings before you start linking. Use File->Settings->User->Color Management or hit the Color Management Settings button on the Source Settings Color Encoding tab to change the behavior. 

Of course, the color transformation of the embedded LUT must match the color space of your editing
project. For example, you must not use a LUT with a target transformation to BT.709 in a project with
Slog3 or HLG color space to avoid wrong colors.

Unlike the settings on the other Source Settings tabs, unfortunately, Media Composer does not support applying the settings on the Linked Plug-in tab to multiple selected clips. So you must enable and disable the application of an embedded LUT for each clip individually.

Avid Playback Settings

The playback quality in the Avid applications can be configured using the Video Quality Menu in the
Timeline window. When the Avid Video Quality menu is set to Full Quality the full 8K, 6K, 4K, or 2K
image is being decoded. At a Draft Quality setting an image of 1/2 resolution is being decoded and at
the Best Performance option, an image of 1/4 resolution is decoded.

For a fluent playback, it is recommended to choose Draft or Best Performance mode. To view images in
best quality choose Full Quality mode.

Working with Sony Proxies

Some Sony cameras can simultaneously record low-resolution HEVC or AVC-encoded proxy files besides the high-resolution AVC or HEVC-encoded main AV stream. Such proxy files are wrapped in MP4 container in the same style as XAVC HS and XAVC S clips.

AVC or HEVC proxies may reside either on the same recording media in the Sub folder or at a separate media. When the proxies are stored on a separate media this media has a similar folder structure as XAVC HS and XAVC S, but the root folder is named PXROOT rather than M4ROOT, already indicating that the recorded footage is of low resolution.

Note that for linking Sony AVC proxy files in the MP4 container the nablet XAVC S AMA plug-in v2.1.1 or later is required. Linking of Sony HEVC proxy clips is supported by this plug-in directly.

To link high-resolution XAVC (MXF) files the nablet XAVC XDCAM plug-in is required. Linking of XAVC AVC(MP4) high-resolution footage is supported by the nablet XAVC S plug-in.

To work with proxy files for editing you must link the high-resolution footage as well as the low-resolution proxy files. Proceed as described below to link the clips and to become able to switch between high-resolution and proxy editing.

1. Link the XAVC HS (MP4) high-resolution footage using the methods described earlier in this manual or the XAVC (MXF) footage using the methods described in the manual of the nablet XAVC XDCAM plug-in or the XAVC S footage using the methods described in the manual of the nablet XAVC S plug-in. Either link the whole volume or link selected clips from the Clip folder.
2. In case the proxy files are HEVC encoded:
   If the proxy clips reside on a separate media, link the whole media by selecting the parent folder above PXROOT, or link selected clips by right-clicking ->Link with->nablet HEVC.
   If the proxy clips were recorded to the same media as the high-resolution clips, navigate to the Sub folder and link all or selected clips by right-clicking ->Link with->nablet HEVC.
3. In case the proxy files are AVC encoded:
   If the proxy clips reside on a separate media, link the whole media by selecting the parent folder above PXROOT, or link selected clips by right-clicking ->Link with->nablet XAVC S.
   If the proxy clips were recorded to the same media as the high-resolution clips, navigate to the Sub folder and link all or selected clips by right-clicking ->Link with->nablet HEVC.

You may link high-resolution clips and proxy clips into the same bin but it is recommended to link them into separate bins for a better overview.

Important! Sometimes the AVC proxy clips have fewer audio tracks than the high-resolution clips. So, special care has to be taken to be able to edit with all audio tracks. If you would fill and edit your timeline directly with the linked proxy clips, you may work for example with 2 audio tracks only while the high-resolution clips have 4 or 8 audio tracks. Relinking the sequence to high resolution later will not add the missing audio tracks!

Beginning with version 1.2.2 of the nablet HEVC plug-in and version 2.1.1 of the nablet XAVC S plug-in, these plug-ins detect the number of high-resolution audio tracks and add silent dummy tracks for the linked proxy clips to match the number of high-resolution audio tracks so that your workflow becomes easier.

This detection will happen always when high-resolution and proxy clips reside on the same media volume.

When high resolution and proxy clips were recorded on separate media it depends on the proxy volumes metadata version whether the number of high resolution is signaled in the clips companion XML file. If it is signaled, this will let the XAVC S plug-in know the number of high-resolution audio tracks and thus how many dummy tracks it will have to add. If it is not there the XAVC S plug-in cannot add dummy tracks upon linking and you have to choose a bit more complex workflow.

You can see the number of audio tracks after linking when the Tracks column on the bin to where you linked the clips is enabled.

So, different workflows are required depending on whether you have to work with a different number of audio tracks or an equal one. Please see the instructions on the following pages.

Note that when you have a proxy or high-resolution clips with a varying number of audio tracks, e.g. some clips have 4 channels, some clips have 8 channels, and the first clip you add to a new sequence has fewer channels than others, then Media Composer will only automatically create this number of audio tracks. When you place a clip with a higher number of channels later on in the sequence, no additional audio tracks will be created, and not all audio tracks of that new clip will be present.

Make sure your sequence has enough audio tracks and manually add additional audio tracks to the sequence before you place clips with a higher number of tracks.

If the number of high-resolution audio tracks is equal to the number of audio tracks shown for the linked proxy clips in the bin columns:

Fill and edit the timeline with the proxy clips. When you are done with editing select the sequence in its bin and raise the Relinkdialog by right-clicking ->Relink... to relink the sequence back to high resolution:

All high-resolution and proxy clips shall have been linked already so that they can be located in the media database by the Relink process.

High-resolution and proxy files typically carry the same source File ID. This is used by the host to identify the matching source clips for relinking.

As the format and image dimensions of high-resolution and proxy clips are different by nature make sure to allow Relink to: Any Video Format. then select Highest Quality as Relink method.

In some cases, the high-resolution clips and the proxies have different frame rates. Make sure to enable Allow relink across rates, otherwise, only clips with the same framerate get relinked.

Check the Create new sequence if you want the selected sequence to be relinked into a copy.

To switch a sequence back to proxy resolution proceed as above but select Relink Method: Most Compressed.

In some cases, when the high-resolution clips are of AVC format and the proxy clips are of HEVC format, the above relink methods may not work as expected. When relinking method Most Compressed is chosen the high-resolution clips get linked and vice versa.

A recommended workflow here is to use Relink to set to the Video format of the current project only... to relink to high resolution:

Where the project dimensions and framerate must match the source material parameters.

To link back to the proxy use Relink to set it to the Any HD video format or to the Any SD video format, depending on the resolution of the proxy clips:

If the number of high-resolution audio tracks is higher than the number of audio tracks shown for the linked proxy clips in the bin columns:

You need to relink the high-resolution clips to low-resolution before you start editing. But only the video track.

1.   Select all high-resolution clips in their bin and right-click->Relink... to raise the Relink dialog and configure the relink process:

As said earlier, all high-resolution and proxy clips shall have been linked already so that they can be located in the media database.

High-resolution and proxy files typically carry the same Source File ID. This is used by the host to identify the matching source clips for relinking.

As the format and image dimensions of high-resolution and proxy clips are different by nature make sure to set the Relink to: to Any Video Format. Select the Mostcompressed as the Relink method.

It is important to select only the Video track to be relinked and keep the audio tracks as a high resolution! This way the relinked clips will still refer to all high-resolution audio tracks.

In some cases, the high-resolution clips and the proxies have different frame rates. Make sure to enable Allow relink across rates, otherwise, only clips with the same framerate get relinked.

2.      Now you may create the sequence and start editing by filling the timeline with their linked clips from the high-resolution bins. You will see that the video track appears as a low resolution but all high-resolution audio tracks are available on the timeline.

3.      Torelink a sequence with a low-resolution video source back to high-resolution for export, high-quality rendering, and preview, select the sequence in its bin and raise the Relink dialog by right-clicking->Relink... to relink the sequence:

To switch a sequence back to proxy resolution proceed as above but select Relink Method: MostCompressed.

On some macOS versions relinking the sequence might not work as shown above. The video track on the timeline may stay at a low resolution.

Instead, select the high-resolution clips in their bin again and proceed as above but select Relinkmethod: Highest Quality. Again only relink the Video track!

The video track on the sequence will change its resolution too.

To relink a high-resolution sequence back to proxy format, proceed as above but select Relink method: set to Most Compressed.

Note that if you had linked the HEVC proxy clips before with the nablet HEVC plug-in earlier than v1.2.1 or the AVC proxy clips with the nablet XAVC S plug-in earlier than v2.1.0 or had linked them with Media Composer's built-in plug-ins, the clips will not be detected by the Relink process.

You must remove the clips from the project, clean the media database first and then link the proxy clips as well as the high-resolution clips.

Choosing the HEVC decoder on Windows PC

Mac users can skip this chapter. There is no manual choice for the user between a hardware-accelerated decoder or a pure software decoder when the plug-in is running on macOS. It is all managed by the OS based on the hardware configuration of your Mac.

On modern Windows PCs, mostly there is more than one decoder available. Besides the software decoder of the plug-in, which is always available, there may be hardware-accelerated video decoders available. This can be the Intel Quick Sync Video decoder if your system is running with an IntelCPU of the Sky Lake family or later, or the decoder of an NVIDIA or AMD GPU if the system is equipped with a modern discrete graphics card.

By default, the plug-in decides automatically which decoder it uses. It prefers the HEVC decoder of a discrete GPU if that is available and supports the video profile of footage to be linked. If no supporting GPU is found it looks for the Intel Quick Sync Video decoder and falls back to using the software decoder if no supporting hardware accelerated decoder is found. This is the procedure for video with 4:2:0 chroma sub-sampling. Footage with 4:2:2 sub-sampling is mostly decided by the software decoder on the CPU for now, because currently there is almost no hardware decoder available that is capable to handle 4:2:2.

The behavior of the plug-in to automatically choose the decoder should be sufficient in most cases and you won't need to intervene. But there may be a few cases where it is good to have the means to override the plug-in's default behavior. This can be when a specific type of footage is not properly decoded on the GPU. Or, this is probably a rare case, the decoder of the discrete GPU is less powerful than the Intel Quick Sync Video decoder of your CPU, or even your CPU is so powerful that it outperforms the hardware-accelerated decoders when using the software decoder.

During the installation of the plug-in also a small tool called nablet HEVC AMA Plug-in Configurator, which allows changing the default behavior of the plug-in is installed. You can find a shortcut on the desktop or run it from the Windows Start Menu under nablet HEVC AMA Plug-in.

Please shut down Media Composer before you run this tool, or restart it after you have made your choice to make the change take effect.

Known Issues and Limitations

• HEVC video files with variable frame rates, for example, recorded by some smartphones, are not yet fully supported. Such clips can be linked and played, but longer clips may lose audio synchronization. Transcode longer clips to constant framerate by third-party tools before linking. Note that in professional video production frames of constant duration are expected. It is not recommended to use devices that shoot VFR only for shooting interviews or other scenes where audio/video synchronization is important.
• On systems with no GPU or with a GPU that doesn't support decoding a specific type of HEVC video, the plug-in will fall back to software decoding on the CPU. A powerful CPU is required for smooth playback.
• For real-time playback of HEVC video set Avid’s NLE Video Playback Quality setting to Draft or Best Performance.
• Depending on the performance of the GPU or CPU and the parameters of the HEVC video stream a real-time playback may not be possible, but transcoding to a proxy format or DNxHR intermediate codec after linking is an option to enable smooth editing.
• On AMD GPUs with driver sets before 2020.7.1some footage will not be properly decoded and show color shifts. Please update drivers to 2020.7.1 or later
• Decoding of footage with 4:2:2 chroma sub-sampling is not supported under macOS 10.13. Please upgrade to macOS 10.14 or a later version.
• After transcoding a clip or after performing a video mixdown, which always requests the plug-in to provide frames in the highest quality, some versions of Media Composer don't reset to the desired lower video playback quality when playing back the source file or timeline. Toggle the Video Quality setting once when you encounter a performance loss during playback.

Notes for System Administrators

Windows system administrators who deploy the plug-in binaries to other systems without running the plug-in installer and thus are not installing the nablet XAVC S AMA Plug-in Configurator application on them can overwrite the default hardware decoder selection behavior by setting a registry key

HKEY_CURRENT_USER\SOFTWARE\nabletGmbH\XAVC S AMA Plug-in
DecoderPreference=0

Values are:

• 0 – Auto – prefers external GPU (default)
• 1 – Force using Intel Quick Sync Video if available
• 2 – Force using a software decoder