Transcoding in Silverstack and Silverstack XT

Overview

The transcoding functionalities of Silverstack have been updated with Silverstack 6. The update contains a faster transcoding engine, an updated user interface, more transcoding options and a lot more (details below).

Silverstack separates the configuration of the transcoding settings from the actual starting of a transcoding job:

  • The section “Transcoding Configurations” will explain how to adjust the settings for your transcoding job.
  • The section “Starting a Transcoding Job”  will explain how to execute a transcoding job.

Transcoding Configurations *

Silverstack XT offers multiple custom transcoding configurations while Silverstack offers one custom transcoding configuration.

The transcoding settings can be found in the transcoding tab of the right bar. Click the transcoding icon to access the transcoding tab:

Fig. 1: Configure the transcoding settings in the transcoding tab of the right sidebar

The upper part of the transcoding tab shows the custom transcoding configurations. The lower part shows the detailed settings for the selected configuration. The settings will be applied and stored to the configurations immediately.

Locking Transcoding Configurations

Fig.2: Locking transcoding configurations

Fig.2: Locking transcoding configurations

Transcoding configurations can be locked to avoid changes to them by clicking the lock icon on the right side of the “Settings” header bar. Locked configurations will be shown with a white lock icon in the table*.

Transcoding Settings

Audio & Video

Video

  • Codec: Select the output codec depending on your requirements. There are different options available (also shown in Fig. 3):
    • H.264 (Quicktime Container)
    • H.265 / HEVC (Quicktime Container, available starting from macOS 10.13)
    • ProRes 4444
    • ProRes 422
    • ProRes 422 (HQ)
    • ProRes 422 (Proxy)

 

Fig. 2: Available transcoding options

Fig. 3: Available transcoding options

  • Container: Select the container for the file. The following options are available:
    • Quicktime (.mov): Available for all codecs  (ProRes, H.264, HEVC)
    • MP4 (.MP4): Available for H.264 and HEVC codecs.
  • Size (for H.264 and ProRes): This drop down menu allows you to select the final resolution of the transcoded clips:
Fig. 3: Available frame sizes

Fig. 4: Available frame sizes

  • H.264 Bitrate Options: 
Fig. 4b: The H.264 bitrate calculator

Fig. 4b: The H.264 bitrate calculator

The H.264 manual bitrate options allow you to enter a specific bitrate in the textfield or provide help for a choice of quality in the “H.264 bitrate calculator” (see fig. 4b).

The bitrate calculator lets you choose the intended quality from “poor” through “good” to “best” and calculates the resulting bitrate based on the selected resolution and the intended frame rate.

  • Duration (Limit to In/Out points): By enabling this option Silverstack only transcodes the part of the clip between the in and out points set in the library.

Audio

Tick the checkbox to include audio in your transcoded clips.

  • Format:
    • Linear PCM
    • ACC – Good Quality **
    • ACC – High Quality **
  • Channel Layout:
    • Stereo Mixdown: The custom audio mix created in the audio panel

Source

Many source formats allow lower-quality decoding to speed up the decoding process (e.g., ¼ resolution decoding) or extra high-quality modes for the best image quality results. You can manually configure your preferred decoding resolution in the transcoding presets’ source section. If the preferred decoding resolution is not available for the source format that is to be transcoded, the next best available mode will be used (e.g., Sony X-OCN does not support the ⅛ res. decoding mode → transcoding will automatically switch to ¼ res. decoding).

Selection of the preferred decoding resolution

Per default, Silverstack is configured to use the “Auto Select” mode, which automatically chooses the preferred decoding resolution for each transcoding task individually, based on the source resolution and the target resolution (e.g., source resolution 8k, target resolution 2k → automatically chooses “¼ res. decoding”  – if supported for source format). Some non-RAW formats implicitly decrease color bit depth when using lower decoding resolutions. To prevent this behavior, the “Always use full color depth decoding” option automatically forces full resolution decoding in those situations.

“Auto Select” mode and full color depth option

It is possible to check the transcoding quality parameters that were actually used for each transcoding task in the “Task Details” section of the job view.

Compositing

  • Resizing:
    •  Fitting Strategy:
      • The zoom to fit (Adding black bars/Without black bars) option will adjust the horizontal resolution of the clip to fit in the selected final size.
      • Zoom to fill will affect the vertical resolution of the footage to the final size, cropping the sides.
      • 1 to 1 will zoom the footage to 100% in the center of the image to adjust to the final selected size, cropping everything else.
figure 6

Fig. 5: resizing example results

  • Grading: 
    • Look Source: Choose how to manage the color data for the clip:
      • As set in Library: enable this setting to include the looks applied to the clip in the Library. For more information on how to apply looks, please check the article The Silverstack Look Library.
      • None: Disables the color processing and transcodes the clips unmodified (as recorded).
      • From file: Reads the clip metadata and applies the color processing described in the embedded looks. In case there is no look embedded, Silverstack applies the default Log to Rec.709 conversion for the specific format.

Overlays

  • Burn Ins: Choose from two different options to burn into the transcoded clip:
Fig. 5: Burn in options

Fig. 6: Burn in options

 

  • Burn in Parameters: The following parameters can be adjusted for the burn ins:
    • Margins: A horizontal and vertical margin to position the burn ins in the frame.
    • Font: Sets the font style for the burn ins.
    • Font Size: Sets the font size in pt.
    • Transparency: Sets the transparency level for the burn ins.
    • Text Color: Sets the text color to “White” or “Black”
    • Background: Sets the background to a “Box” shape, adds an “Outline” to the text or with “None” adds no background.

 

  • Image Overlay: Choose an image overlay (.png, .jpg, .tiff) to be burned into the transcoded clips.

 

  •  Image Overlay Parameters:
    • Size: Sets the size of the image (0 -100 %)
    • Position X: Sets the position in horizontal direction
    • Position Y: Sets the position in vertical direction
    • Transparency: Sets the transparence (0 – 100 %)

The Transcoding Preview

When the transcoding tab in the right bar is showing Silverstack automatically switches to a transcoding preview to be shown in the playback view:

Fig. 6: The transcoding preview

Fig. 7: The transcoding preview

The transcoding preview displays a preview of the transcoding configurations applied to the currently selected clip.

Starting a Transcoding Job

The «Transcode» button

The «Transcode» button

 

In order to start transcoding the clips, first select a folder or bin in the Library panel. Then click on Transcode to open the wizard. There you will be able to select the clips you want to transcode. Click on continue to select the destination and transcode settings.

 

figure 1: clip selection wizard

Fig. 8: clip selection wizard

 

Now you are able to select where the transcoded clips will be stored. You can add and remove destinations by using the «+» and «-» buttons. Alternatively, it’s also possible to modify each destination path and path wildcards. You can select from the configurations previously configured in the transcoding configurations tab:

Fig. 9: The transcoding destination step

Fig. 9: The transcoding destination step

Click the current configuration to open the list of all available transcoding configurations:

Fig. 7: The pre-installed transcoding configurations

Fig. 10: The transcoding configurations dropdown

When the checkbox “Add to Library” is checked the transcoded clips will automatically be ingested into the Silverstack Library after the transcoding job is done. Transcoding statistics will be available for the clips in the statistics view.

Click “Start Render Job” to start the render job. It can then be traced in the jobs panel.

Path Wildcards for Transcode Destinations

Path Wildcards can be used to customize the transcoding path with available metadata. Click the “Path wildcard” icon in the status bar (see fig. 13) to access the path wildcards settings for the selected destination:

Fig. 11: The path wildcard window

Fig. 11: The path wildcard window

It is also possible to rename the transcoded clips by leaving out the “/” and optionally also adding a file extension. Here’s an example:

Fig. 12: Path wildcards for transcoding destinations

Fig. 12: Path wildcards for transcoding destinations

Hint: It is also possible to copy and paste path wildcards like plain text.

Multi Destination Transcoding*

Silverstack XT is able to transcode to multiple destination formats at a time. In certain cases (see below), the transcoding of the configurations has to be run sequentially. The transcoding wizard will give you a hint if the transcoding will be run in parallel or sequentially:

Fig. 8 : The info message about parallel or sequential transcoding

Fig. 13 : The info message about parallel or sequential transcoding

In case of sequential transcoding you can open theWildcards for Transcodes panel to get details about the transcoding order.

The following settings can influence the parallel execution of the transcoding job:

  • In/Out Points
  • Debayer settings
  • Decoding resolution

Make sure to set the above settings to the same value when transcoding to two different configurations to avoid sequential transcoding.

Management of Transcoding and Offload Jobs

Silverstack Lab is generally able to transcode and copy at the same time. Transcoding jobs as well as copy jobs run in the background while the app is still fully accessible.

Optionally you can choose to pause transcoding jobs when offloading and while playing back clips. To do so go to the “Copy&Jobs” tab in the Preferences and select the according checkbox “Automatically Interrupt Transcoding Jobs during Playback and Offload”:

Fig. 14: The "Copy&Jobs" tab in the preferences

Fig. 14: The “Copy&Jobs” tab in the preferences

Transcoding Functionalities Overview for Silverstack and Silverstack XT

The transcoding functionalities of Silverstack have been updated with version 6. Silverstack and Silverstack XT come with a different set of functionalities concerning Transcoding.

  • Silverstack 
    • Single destination transcoding
    • One custom transcoding preset
    • Timecode and Clip Name burn in options
    • Watermarking
    • Transcoding resolution up to full HD (1920 x 1080)
    • Stereo mixdown audio channel layout for transcoded clip
  • Silverstack XT
    • Multi destination transcoding
    • Many custom transcoding preset
    • Timecode and Clip Name burn in options
    • Watermarking
    • Transcoding resolutions higher than Full HD (1920 x 1080)
    • Stereo mixdown audio channel layout for transcoded clip
    • Transcoding statistics

 

 

* Silverstack XT only

**Only available for ProRes and H.264