This article describes how to adjust the video decoding in the Wowza Transcoder through the use of video decoding parameters. Users with advanced decoding knowledge can log all of the video decoding parameters that are available, and their current values, and use this information to adjust the transcoding parameters for transcoded streams.
Note: A Transcoder template has just one <Decode> block (<Decode>...</Decode>), which represents the decoding process. Video decoding parameters you apply will affect all transcoded streams. To have more control of the transcoding process, you can apply video parameters to individual stream output renditions as they're transcoded. For more information, see How to control transcoded video with video encoding parameters.
Contents
Logging available video decoding parameters
Configuring video decoding parameters
More resources
Logging available video decoding parameters
When using Wowza Transcoder, you can log all available video decoding parameters with their current values for the <Decode> block to the wowzastreamingengine_access.log file. To do this, open the transcoder template file in a text editor and add the following property to the <Properties> container in the <Decode> block in the transcoder template:
<Property> <Name>logVideoDecodingParameters</Name> <Value>true</Value> <Type>Boolean</Type> </Property>
TranscoderWorkerVideoDecoder.setupDecoder[_defaultVHost_:live/_definst_/myStream: decodeIterations:0]: Video decoding parameters # long: dpb_size: Set DPB size option mainconcept.dpb_size: 0 # long: deinterlaceDoubleRate: 0:single rate (default), 1:double rate default.deinterlaceDoubleRate: 0 # long: optCPUNum: Sets number of logical CPUs, which can be used in specified SMP mode by the optSMPMode command mainconcept.optCPUNum: 4 # long: optACCMode: Hardware acceleration mode: 0:ACC_MODE_NONE, 1:ACC_MODE_DXVA1, 2:ACC_MODE_DXVA2, 3:ACC_MODE_NVCUVID mainconcept.optACCMode: -1 # long: output_8bit: Allow only 8bit output image option: 0:off, 1:on mainconcept.output_8bit: 0 # long: deinterlace: 1=default (field interpolation top),256=field interpolation top, 768=field interpolation bottom, 512=vertical smoothing (add 2048 to reorder fields) default.deinterlace: 0 # long: optSMPMode: Sets symmetric multiprocessing (SMP) mode of decoding: 0:SMP_NONE, 1:SMP_BY_PICTURES, 2:SMP_BY_SLICES mainconcept.optSMPMode: 1 # long: maxTemporalLayer: Set maximum layer to be decode (default is 8) mainconcept.maxTemporalLayer: 0 # long: ec: Set Error concealemnt modes (bitmask): 0:NONE, 1:SHOW_BASE_LAYER (SVC only), 2:CONCEAL_ERROR_FRAMES, 4:TEMPORAL_FOR_INTRA, 8:ERRORLESS_REF_ONLY mainconcept.ec: 0 # long: loop_filter: Set loop filter mode option: 0:off, 1:on mainconcept.loop_filter: 1 # long: mv_precision: Limits precision of motion vectors option: 0:PRECISION_QUARTER, 1:H264VD_MV_PRECISION_HALF, 2:H264VD_MV_PRECISION_FULL mainconcept.mv_precision: 0
Note: The data logged will vary depending on the hardware in use and the codec applied to each transcoded output rendition.
Configuring video decoding parameters
You must use a text editor to configure video parameters in the transcoder template files ([install-dir]/transcoder/templates) in your Wowza Streaming Engine™ installation. They can't be configured using Wowza Streaming Engine Manager.
Open the transcoder template file in a text editor and add a <Parameter> section to the <Video>/<Parameters> container in the <Decode> block, as shown in the example below. Then restart the Wowza media server for the changes to take effect.
Note: Older versions of the example transcoder templates may not have a <Parameters> container for the <Video> decoding section. Add this container if it's missing from your transcoder template.
Example configuration
As an example, for this deinterlace rate method video parameter defined as available and in use in the wowzastreamingengine_access.log file:# long: deinterlaceDoubleRate: 0:single rate (default), 1:double rate default.deinterlaceDoubleRate: 0
<Parameter> <!-- 0:single rate (default), 1:double rate --> <Name>default.deinterlaceDoubleRate</Name> <Value>0</Value> <Type>Long</Type> </Parameter>
More resources
How to control transcoded video with video encoding parameters
How to control transcoded audio with audio encoding parameters
How to set up and run Wowza Transcoder
If you're having problems or want to discuss this article, post in our forum.
