Links

• Release video overview
• Update instructions
• Update details on blog

Full List of Changes

• Added ability to configure the PDF export command timeout. (#5119)
• Added new Lexical based editor. (#5058)
• Added not operator to search. (#4536)
• Added OpenSearch support. Thanks to @maximilian-walter. (#5198)
• Added SAS and R code language support. (#5206)
• Added search term negation support. (#5239)
• Added Welsh language to language list. (#5240)
• Updated dompdf and bacon-qr-code libraries to new major versions. (#5222)
• Updated page editor type to always exist in API and database. (#5117)
• Updated translations with latest Crowdin changes. (#5188)
• Updated user account creation to provide better email failure feedback. (#5195)
• Fixed drifting search icon on smaller screen sizes. (#5204)

Core

Fixes

• Fix bad config file examples
• Fix casparcg_auto_restart.bat not starting scanner
• Revert removal of tbbmalloc, due to notable performance loss on windows
• Supress some cmake build warnings
• Build failure when doxygen installed on system
• Build failures with ffmpeg 7.0
• Revert RPATH linking changes

Producers

Fixes

• FFmpeg: Ignore ndi:// urls
• FFmpeg: Using both in and seek could result in incorrect duration
• Route: Race condition during destruction
• Image: Update freeimage on windows with some CVE fixes and failures with certain pngs
• Image: Respect EXIF rotate flag
• NDI: list local sources

Consumers

Fixes

• Decklink: subregion copy not respecting frame height
• Decklink: subregion vertical offset
• Decklink: subregion height limited with some formats

Full Changelog: v2.4.0-stable...v2.4.1-stable

Pure bug fix release.

Fixes include:

• Fixed cruicial bug/crash when monitoring growing files.
• Fix stills encoder bug when extracting single image.
• Fix potential race condition bug when several nodes are parsing same media source.
• Fixed rare API bug when submitting huge JSON bodies.
• Fix a color scheme bug in manager when showing bypassed nodes.
• Fix all running workflows restarting when stopping just one.
• Fixed a bug that could cause FFAStrans to not clean up old jobs/logs.
• Fixed some agressive enumration of history records.
• + Several other minor fixes.

Pure bug fix release.

Fixes include:

• Fixed some illegal characters when parsing mac alias
• Fix occational double registration of new monitored files
• Fix loudness analyser not storing correct real peaks data
• Fixed rare error that sometimes caused retried jobs to not start
• Fix audio files getting double length when converting to video formats
• Update BMX to include fix for wrongly flagged aspect ration on some MPEG-2 formats.
• Fixed rare bug that sometimes cause FFAStrans to not continue with jobs containing priority splits.

Pure bug fix release.

Fixes include:

• Fixed SAR was not set when auto cropping IMX source in the A/V Decoder
• Fixed Interlace analyze node reported bogus results
• Fixed wrong progress on video analyze node
• Fixed rare issue where priority branches did not end properly
• Fixed issue that in some conditions caused a job queue to build up
• Fixed A/V Decoder not properly decoding some broken MPEG2
• Removed bogus 4:4:4 AVI option in the Uncompressed encoder node
• Removed too strict variable check when submitting jobs via API

Pure bug fix release (1.4.0.1 – 1.4.0.4).

Fixes include:

• Fixed continously growing files being picked up too early
• Fixed multiple hosts picking up the same growing file
• Fixed loudness analyser not returning correct channel layout
• Fixed error in priority splits
• Fixed stills decoder having malformated color conversions.
• Fixed rare crash on badly formated time code
• Fixed a file locking anomalie
• Fixed a handle leak in the queuer

Finally, long overdue, a new version that does not only focus on fixes and improvements but a set of new nice long awaited features.

Changes include:

• New core features:
  • Hosts group: Group hosts into different named groups and assign nodes or/and workflows to them
  • Job slots per node: Assign a higher number of job slots to a node in order to better “allocate” resources on the executing host
  • Cron scheduling support for monitors
• New functions:
  • $dateweek(): Calculate week numbers
  • $timecalc(): Time calculator
  • $waccess(): For testing write access
  • $owner(): For getting owner of a file
  • $asplit(): Split/format array into a string
  • $ffconcat(): For creating a “ffconcat version 1.0” string
  • $shortcut(): For parsing Windows shortcuts and macOS alias files
• New variables:
  • %i_v_precharge%: Get precharge value from MXF files
  • %s_options%: System variable for advanced altering of job behavior
  • %f_pix_aspect%: Pixel aspect ratio as float
  • %s_frame_rate%: Represent frame rate as num/denum string
• New API method:
  • GET /jobvars/ for getting final value of user variables after job end
• Improved processing speed, quality and color precicion for all encoders
• Huge database I/O optimizations for thos with larger farms
• Dolby E decoding in the “A/V Decoder” (Experimental)
• “Forget missing files” are now supported by all applicable monitor nodes
• Support the new frame properties in AviSynth+
• Support Mac alias in the “Folder” monitor and improved Windows shortcut support
• Improved support for encoding files with cover art
• Properly support audio buffer files > 4GB in the “A/V Decoder”
• Support reading stdout/err in command executor as unicode
• Support XDCAM-EX 35 720p in the “XDCAM-HD” encoder
• Support multiple selection in the status monitor
• Inbuilt status monitor now shows history pages instead of one huge list
• Improved “Color conversion” filter
• Improved navigation in the status monitor using arrow keys
• Improved up-time reliability
• Native support for “ffconcat version 1.0” input sources
• Native support for reading IMF files
• Support writing 64 bit audio files in the “Extract audio” node
• Support UTF-8 formated mail bodies in “Send E-Mail” node
• Playlist support in “YouTube” decoder and save list to variable
• Clear complete work cache dir from FFAStrans Manager
• Support SinPowResize kernel in “Resize” filter
• Improved automatic cleaning of log and work files
• FFAStrans will now archive job logs and keep them for an extended period
• Fix several long path issues in monitors and FTP delivery
• Fix slow opening of long workflows
• Fix comparing negative number not working in the “Conditional” node
• Fix graphical artifact when moving too far out on a large workflow
• Fix some number like strings being strictly regarded as number
• + Lots other minor fixes and improvements

Bug fixes, improvements and minor features update.

Changes include:

• Added 4:4:4 profile (XQ) to the ProResKS encoder.
• Added “MXF (BMX)” wrapper option to the Panasonic P2 monitor.
• Added option for removing farming settings when exporting workflows
• Added PUT method for updating existing workflow through API
• Added user option to read from STDERR and/or STDOUT in the “Command executor” node.
• Improved general robustness when executing many jobs at the same time.
• Reduced general priority on sub processes in order to not halt system.
• Fixed some special case FTP monitor issue that caused files to not be downloaded properly.
• Fixed framerate bug when encoding to BMX (MXF)
• Fixed an issue where setting %s_source% to “” (nothing) resulted in some erratic behavior.
• Fix some job retry issues.
• Fix audio config crash in the DV encoder.
• Fixed rare memory leak issue.
• Fixed MOV bug in the DNxHD encoder
• Fixed a problem with the A/V Media decoder created zero-length clips.
• Fixed an issue that caused some image sequences to not be properly parsed
• Fixed a problem where plugin processors GUI got stuck behind manager window.
• Fixed a bug where the “Fade” filter ignored audio/video enable/disable
• Fixed an issue that caused the “Custom FFmpeg” encoder to not work properly when using custom ffmpeg mapping.
• Fixed an API issue where history was not always correctly returned.
• Fixed an issue causing some AviSynth based video filters to not work properly on older CPUs
• Fixed a flaw with priority connections in conjunction with executing on error.
• ++ Several other minor improvements and fixes

Pure bug fix release.

Changes include:

• Fix progressive closed GOP encoding in the XDCAM-HD not working.
• The “Video quality” node would sometimes return a bogus “inf000000” value.
• The “Video quality” would fail if source or ref was IMX-D10 content.
• The “%s_cache_record%” variable was not correctly populated.
• Fix the “Sequence” monitor disregarding the “Recurse” setting.
• The “Sequence” monitor would sometimes not work due to an invalid input option being set.
• Two succeeding encodings on the same branch could fail if using the inbuilt encoders.
• Fix minor issues with properly recognizing some pixel and color formats when processing.
• The loudness table in “Audio extract” encoder gui did not set a value.
• A few other minor edge case issues addressed.

Pure bug fix release.

Changes include:

• Fixed potential endless loop in “A/V Decoder” node.
• The XDCAM-HD encoder would sometimes stop encoding on very complex content.
• Fixed an issue where sources with yuvj420p pixel format would sometimes lead to failed encoding.
• Fixed an issue that caused bad frame rate conversion on small fps difference between source and output.
• Fixed an issue where host settings was not properly saved.
• Fixed error message on multiple immediate retries from failed node..

Finally a new version that does not only focus on fixes and improvements but has a lot of new nice features to present.

Changes include:

• New workflow features:
  • Sub splits: This feature enables sub connected splits (brown) to always finish before the main splits (black).
  • Workflow connection: Enables you to forward a job to another workflow.
• New functions:
  • $lookup() and $lookuprep() for table lookup and lookup replacement.
  • $sort() for sorting an array or a string.
  • $split() for splitting a string into an array.
  • $count() for counting occurrences of a string or single character.
  • $foreach() for dynamically executing operations on an array
  • $string() for formatting strings like printf in C.
  • $xxhash64() for 64 bit version of xxhash.
• New node: “For each”: Will loop through an array of values and dynamically create a new split/branch for each index.
• New variables:
  • %s_start_tc_alt% for alternative start TC taken from creation date of media.
  • %s_gamma% for gamma curve of media
  • %s_chroma_loc% for chroma location of media.
  • %i_gmt_bias% for the local GMT bias.
  • %s_version% for current running FFAStrans version.
  • %s_last_error% for retrieving last viable error message.
• New API methods.
  • GET /workflows/status for getting current status
  • POST /workflows for importing FFAStrans exported workflows.
  • POST /presets for importing FFAStrans exported presets
  • POST /user_variables for importing FFAStrans exported user variables
  • GET /history now supports ?start and ?count for getting custom range
• All encoders now support applying custom or inbuilt LUTs.
• All encoders now support setting and converting full/limited video range.
• Huge speed improvement when muxing to BMX MXF as FFAStrans no longer creates an intermediate file before remuxing.
• Added search function in the variables selector.
• Added free text search function for workflows and nodes.
• The XAVC node now support class 300 and 480 in UHD.
• The AVC-Intra node now support class 2K and 4K.
• Added option to use user variables as framerate in “ProRes” and “DNxHR” encoder nodes.
• Added user selectable quality tunings to the the “XDCAM-HD” node.
• Added “Writing library” mode to the “ProRes” encoder node for improved compatibility in some scenarios.
• Added HLG and PQ signaling to the “H.264” encoder.
• Added option to save complete VMAF json to a variable in the “Video Quality” node.
• Added access to the user variables from main manager menu.
• Added user selectable zero padding to unique output file names in the delivery nodes.
• The header section in “HTTP communicate” node now supports using variables.
• The “%s_original_path~n%” variable now supports minus notation for retrieving path names from the right side.
• The “%s_recursed_path%” variable now support the same notation type as %s_original_path~n% with %s_recursed_path~n%.
• Added option to export job logs from inbuilt status monitor.
• The “Hold” node now supports arrays as list of files.
• Updated to use the new maintained yt-dlp instead of youtube-dl.
• Changing a variables/static name now automatically updates all applicable workflows.
• Expanded the $exists() function to support path recursing and returning a file list in array.
• Added support for adding data to an existing array using the $jsonput() function.
• Fixed issue where the “H.264” encoder produced corrupt MXF files.
• Fixed various bit depth issues in the “H.264/5” encoders.
• Fixed “Generic MPEG” was forced to 16:9 aspect.
• + Lots of minor changes and improvements.

Pure bug fix release.

Changes include:

• Growing files functionality was broken.
• Running workflows without any nodes would crash.
• Time stamps had the wrong notation when GMT was +00.00
• Fixed rare crash with inbuilt status monitor when applying action to a finished job.
• First time initialization of user variables would sometimes crash.
• Loudness input field did not always parse variables correct.
• Fix rare bug that could cause status monitors to miss data.
• Fix wrongfully hardcoded 16/9 aspect in the generic MPEG encoder.
• The API url /workflows/<wf_id>/user_variables did not always produce correct reply.
• The API url /tickets url could in some cases return an invalid json.

Bugfixes and minor changes:

• Fixed an issue with the update mechanism

Bugfixes and minor changes:

• Fixed a regression introduced in 1.9.0, the "public IP or hostname" field on the passive mode page was not restored when opening the settings dialog

Fixed vulnerabilities:

• MSW: Warn if installing the server outside of Program Files due to custom directories having too lax permissions

Bugfixes and minor changes:

• Fixed a race condition resulting in stalled connections
• *nix: Fixed a potential crash if SIGINT is sent to the server while it is shutting down
• Fixes to the update check mechanism
• Fixed a regression in the converter for old 0.9.x configurations dealing with placeholders in native paths

New features:

• Private keys used for TLS can now be stored on a PKCS#11-compatible token device; the UI has been updated accordingly.
• UI: added button to retrieve the current FileZilla Server's public IP address, useful to configure the PASV mode.
• UI: added an FTP connection test, that can be reached directly from the Server menu item or executed at the end of the FTP Network Configuration Wizard.
• Made default values more secure, among which: require TLS on new FTP listeners, require a password for new users and warn if the administration password doesn't meet more stringent security requirements.
• Fixed bug causing the most recent log file, rather than the oldest, to be deleted upon rotation, when using dates as suffixes.
• MSW: fixed regression causing socket listener conflicts due to recent libfilezilla changes.
• Added WebUI: an HTTP server providing a REST API and a web app for seamless web access to stored files. WebUI is not included in the default build and must be enabled with the --enable-webui parameter during compilation. This feature is experimental; feedback and bug reports are welcome.

Bugfixes and minor changes:

• UI: the certificate fingerprint verification dialog is now sized to display the full fingerprint at once.
• UI: fixed bug causing the focus to be lost during user editing.
• UI: fixed bug causing the tray icon to display unexpectedly in certain cases.
• UI: improved error handling in case of server disconnection.
• UI: improved handling of Settings window size on ultra wide screens.
• FTP: the MKD command now returns an error if the directory already exists.
• FTP: Improved login timeout handling to exclude internal server processing time.
• Fixed heap corruption in the Administrator Interface.
• Fixed regression in the path handling routines.

Bugfixes and minor changes:

• MSW: Fixed an issue with confirmation dialogs for file deletion not being modal
• Updated to libfilezilla 0.48.1

Bugfixes and minor changes:

• Fixed an issue migrating old queue files if several older versions have been skipped
• Updated to libfilezilla 0.48.0

Fixed vulnerabilities:

• FileZilla Server now requires that the configuration directory is owned either by the operating system user account the server runs under, or a more privileged user (SYSTEM, Amdministrators, TrustedInstaller on Windows, root elsewhere)
• MSW: Mount points are now case-insensitive so that restrictions on sub mounts cannot be bypassed by a change of character case

Bugfixes and minor changes:

• Fixed a potential deadlock during transfers
• FTP: Fixed potential crash if the session gets closed

Fixed vulnerabilities:

• SFTP: Fixed PuTTY ECDSA NIST P-521 private key recovery vulnerability (CVE-2024-31497). If you use NIST P-521 keys to connect to SSH/SFTP servers, you should regenerate them and revoke the previous ones.
• Official binaries are now built against GnuTLS 3.8.4

Bugfixes and minor changes:

• Updated to libfilezilla 0.47.0

Fixed vulnerabilities:

• Official binaries are now built againt GnuTLS 3.8.3

Bugfixes and minor changes:

• Updated to libfilezilla 0.46.0
• MSW: Fixed tab navigation over message log

New features:

• Limits to the number of active sessions defined for the groups now apply to the group as a whole, not just to the individual users belonging to those groups.
• Fixed bug that led to timeouts not being set at startup, but only when changing the configuration.

Bugfixes and minor changes:

• FTP Server: NLST would report a file names with a leading ./ path in certain cases, which confused some clients. Fixed.
• UI: Fixed bug that caused the Administration Interface to misinterpret native paths in the mount lists in case the server were running on a machine with different path semantics than the Administration Interface's one.
• UI: fixed regression that led to some message dialogs not being displayed.
• Fixed regression that caused disabled mount points with empty native paths to be discarded.
• Fixed conversion to utf8 of virtual paths, which was wrongly misinterpreting some native encodings.
• In case of login failure, the login timeout resumes counting down for the remaining time.

Changes since 2.4.0 RC 1:

Core

Improvements

• Support 4K DCI frames
• Build: Allow configuring diag font path at build time
• AMCP: Add CALLBG command to perform CALL on background producer

Fixes

• OSC: Background state not being produced
• Scanner: resolve issues with database not being updated

Producers

Improvements

• HTML: Expose cache-path setting

Fixes

• FFmpeg: Unable to play files with extra dots in filenames
• FFmpeg: Support parameters with name containing a dash
• FFmpeg: Audio channels being swapped unexpectedly

Changes since 2.3.3

Core

Improvements

• Custom resultions can be specified in casparcg.config
• Interlaced mixer pipeline to ensure field accuracy
• Preserve unicode characters in console input/output
• Producers to be run at startup can be defined in casparcg.config
• Support 8K frames
• Support 4K DCI frames
• Remove undocumented CII and CLK protocol implementations
• Config parameter can be an absolute system path, not just relative to the working directory
• AMCP: Add CLEAR ALL command
• AMCP: Command batching syntax
• AMCP: LOAD/LOADBG/PLAY commands accept a CLEAR_ON_404 parameter, to instruct the layer to be cleared when the requested file was not found
• AMCP: Add commands to subscribe and unsubscribe to OSC on any port number
• AMCP: Add CALLBG command to perform CALL on background producer
• Build: Require C++17 for building
• Build: Support newer versions of Boost
• Build: Support newer versions of TBB
• Build: Disable precompiled headers for linux
• Build: Support VS2022
• Build: Replace nuget and locally committed dependencies with direct http downloads
• Build: Allow configuring diag font path at build time
• Linux: Support setting thread priorities
• Linux: Initial ARM64 compatibility
• Linux: Rework build to always use system boost
• Linux: Rework build process to better support being build as a system package
• Logging: add config option to disable logging to file and to disable column alignment
• Transitions: Support additional audio fade properties for STING transition

Fixes

• Crash upon exiting if HTML producer was running
• AMCP: Ensure all consumers and producers are reported in INFO commands
• AMCP: Deferred mixer operations were not being cleared after being applied
• AMCP: LOAD command would show a frame or two of black while new producer was loading
• OpenGL: Fix support for recent Linux drivers
• Linux: Fix endless looping on stdin
• Route: Fix error when clearing layer
• Transitions: Fix wipe duration

Producers

Improvements

• Decklink: Require driver 11.0 or later
• Decklink: Scale received frames on GPU
• FFmpeg: Update to v5.1
• FFmpeg: Improve performance
• FFmpeg: Allow specifying both SEEK and IN for PLAY commands
• HTML: Update to CEF 117
• HTML: CALL 1-10 RELOAD to reload a renderer
• HTML: Expose cache-path setting
• NDI: Upgrade to NDI5
• System Audio: Allow specifying output device to use

Fixes

• Decklink: Log spamming when using some input formats
• FFmpeg: Prevent loading unreadable files
• FFmpeg: Unable to play files with unicode filenames
• FFmpeg: Don't lowercase filter parameters
• FFmpeg: Support parameters with name containing a dash
• HTML: media-stream permission denied
• HTML: Expose angle backend config field, the best backend varies depending on the templates and machine
• HTML: Crash when multiple iframes were loaded within a renderer
• Image: Improve file loading algorithm to match the case insensitive and absolute path support already used by ffmpeg

Consumers

Improvements

• Artnet: New artnet consumer
• Decklink: Configure device duplex modes in casparcg.config
• Decklink: Output a subregion of the channel
• Decklink: Add secondary outputs in a consumer, to ensure sync when used within a single card
• iVGA: Remove consumer
• NDI: Upgrade to NDI5

Fixes

• Decklink: Fix stutter when loading clips
• FFmpeg: Fix RTMP streaming missing headers
• NDI: dejitter

Changes since Beta 1:

Important

There is a known bug in the version of media-scanner included in this release.
It is recommended to replace it with v1.3.2 or newer from https://github.com/CasparCG/media-scanner/releases

Core

Improvements

• Config parameter can be an absolute system path, not just relative to the working directory
• Linux: Rework build to always use system boost
• Linux: Rework build process to better support being build as a system package
• Audio: 16 channel audio

Fixes

• Crash upon exiting if HTML producer was running
• AMCP: LOAD command would show a frame or two of black while new producer was loading

Producers

Fixes

• FFmpeg: Unable to play files with extra dots in filenames
• FFmpeg: Don't lowercase filter parameters
• HTML: Debugger connection closes
• HTML: Expose angle backend config field, the best backend varies depending on the templates and machine
• HTML: Crash when multiple iframes were loaded within a renderer
• Image: Improve file loading algorithm to match the case insensitive and absolute path support already used by ffmpeg

CasparCG 2.4.0 Beta 1

Core

Improvements

• Custom resultions can be specified in casparcg.config
• Interlaced mixer pipeline to ensure field accuracy
• Preserve unicode characters in console input/output
• Producers to be run at startup can be defined in casparcg.config
• Support 8K frames
• Remove undocumented CII and CLK protocol implementations
• AMCP: Add CLEAR ALL command
• AMCP: Command batching syntax
• AMCP: LOAD/LOADBG/PLAY commands accept a CLEAR_ON_404 parameter, to instruct the layer to be cleared when the requested file was not found
• AMCP: Add commands to subscribe and unsubscribe to OSC on any port number
• Build: Require C++17 for building
• Build: Support newer versions of Boost
• Build: Support newer versions of TBB
• Build: Disable precompiled headers for linux
• Build: Support VS2022
• Build: Replace nuget and locally committed dependencies with direct http downloads
• Linux: Support setting thread priorities
• Linux: Initial ARM64 compatibility
• Logging: add config option to disable logging to file and to disable column alignment
• Transitions: Support additional audio fade properties for STING transition

Fixes

• AMCP: Ensure all consumers and producers are reported in INFO commands
• AMCP: Deferred mixer operations were not being cleared after being applied
• OpenGL: Fix support for recent Linux drivers
• Linux: Fix endless looping on stdin
• Route: Fix error when clearing layer
• Transitions: Fix wipe duration

Producers

Improvements

• Decklink: Require driver 11.0 or later
• Decklink: Scale received frames on GPU
• FFmpeg: Update to v5.1
• FFmpeg: Improve performance
• FFmpeg: Allow specifying both SEEK and IN for PLAY commands
• HTML: Update to CEF 117
• HTML: CALL 1-10 RELOAD to reload a renderer
• NDI: Upgrade to NDI5
• System Audio: Allow specifying output device to use

Fixes

• Decklink: Log spamming when using some input formats
• FFmpeg: Prevent loading unreadable files
• FFmpeg: Unable to play files with unicode filenames
• HTML: media-stream permission denied

Consumers

Improvements

• Artnet: New artnet consumer
• Decklink: Configure device duplex modes in casparcg.config
• Decklink: Output a subregion of the channel
• Decklink: Add secondary outputs in a consumer, to ensure sync when used within a single card
• iVGA: Remove consumer
• NDI: Upgrade to NDI5

Fixes

• Decklink: Fix stutter when loading clips
• FFmpeg: Fix RTMP streaming missing headers
• NDI: dejitter

Improvements:

• Image Scroll Producer

Producers

Fixes

• Packages: Update TBB library to v2021.1.1 - fixes CPU and memory growth when deleting threads
• FFmpeg: Fix possible deadlock leading to producer not being cleaned up correctly

Producers

Fixes

• Packages: Update TBB library to v2021.1.1 - fixes CPU and memory growth when deleting threads
• FFmpeg: Fix possible deadlock leading to producer not being cleaned up correctly

This is the first patch release for 2.3.

Primarily this contains a crtical fix to provide support for flash templates to be used after the flash player EOL at the end of 2020.
For more information on the issue see: #1352

Thanks to @silid for developing the fix and @didikunz for documenting the process and being a key member of chasing for these releases to be made

See the attached PDF, or the copy in the Zip for steps on how to prepare your system.

For any help or questions, check the forum

Changes

Producers

Fixes

• Flash: Use proper file urls when loading templates, to allow it to work after Flash Player EOL
• FFmpeg: Various HTTP playback improvements

This is a critical fix for the 2.0.7 release, to provide support for flash templates to be used after the flash player EOL at the end of 2020

For more information on the issue see: #1352

This has been built to be as close as possible to the previous 2.0.7 release, to minimise any risk of deployment.

Thanks to @silid for developing the fix and @didikunz for documenting the process and being a key member of chasing for these releases to be made

See the attached PDF, or the copy in the Zip for steps on how to prepare your system.

For any help or questions, check the forum