Creating New Transcoding Profiles

in order for the broadcaster to switch from one encoding to another, different transcoding profiles must be configured first these transcoding profiles include the transcoding settings that can be used for the transcoding of streams supported video and audio formats include video decoding – mpeg2, h 264/avc , h 265/hevc, raw video encoding – mpeg2, h 264/avc , h 265/hevc, raw audio decoding – aac, mpeg 1 audio layer i / ii / iii, mpeg 2 audio layer i / ii / iii, ac 3 (dolby digital), opus for ac 3, which can contain up to six discrete channels of sound, the transcoder only supports the left and right channels and will ignore the other channels audio encoding – aac, aac he (high efficiency), aac hev2; e ac 3 (enhanced dolby digital), mp1 (mpeg 1 audio layer ii), opus or passthrough other audio codecs aac he and aac hev2 are only supported for zixi broadcasters, v13 and up the transcoder comes with the following pre set common video profiles 1080i60 / 1080i59 94, 1080p30 / 1080p25, 720p60, 720p50 / 720p30, 576i60 / 576p25, 480i60 / 480p29 97 you can also define your own custom profiles for downstream satellite workflows, you will probably need to generate constant bitrate (cbr) streams this setting is configured at the individual input level (not the transcoding profile level) to set a cbr, enter the desired transport stream bitrate (kbps) as described in the transcoding broadcaster input streams docid\ n8yumysvhstq6vghqcjdn section to create a new profile in the transcoder page, click + new profile the add new profile window is displayed select the desired codec type mpeg2, h 264 or h 265, or raw video for a video profile or select aac, opus, or raw audio for an audio profile enter the desired fields in the profile configuration (see table below for additional parameters) select a specific preset profile to automatically fill in the default settings for that profile, or select custom to create a new profile from scratch you can edit specific fields of a preset configuration while creating the profile if you want to configure the advanced options for the video profiles, select advanced options and fill in the respective fields (see table below for additional parameters) click apply the newly configured profile is created and appears on the scree transcoding profiles parameters parameter description profile configuration for video mpeg2, h 264, h 265, raw video preset select one of the pre configured presets or select custom to create a new profile from scratch even if you select a preset configuration, you can still change its settings default custom name enter a unique name for the profile encoder select one of the following options x264 – software based encoder (available for h 264 only) nvidia – nvidia based hardware encoder encoding profile select the relevant encoding profiles for h 265 video profiles with hardware acceleration main (default) – this profile supports 8 bit per pixel encoding (bpp) main 10 – this profile supports 10 bit per pixel encoding (bpp) main sp the main still picture profile allows for a single still picture to be encoded with the same constraints as the main profile as a subset of the main profile the main still picture profile allows for a bit depth of 8 bits per sample for h 264 video profiles high the primary profile for broadcast and disc storage applications, particularly for high definition television applications main this profile is used for standard definition digital tv broadcasts that use the mpeg 4 format as defined in the dvb standard baseline primarily for low cost applications that require additional data loss robustness, this profile is used in some video conferencing and mobile applications for mpeg2 video profiles high – supports snr and spatial scalability and intra dc precision of 8, 9, 10, and 11 main supports i and p and b picture coding types and intra dc precision of 8, 9, 10 simple – supports i and p picture coding types and intra dc precision of 8, 9, 10 display aspect ratio select the aspect ration of the video display if you select custom , enter the desired resolution in the resolution field resolution enter the new resolution in pixels, if resizing the video keep source aspect ratio select this checkbox (default) to maintain the original aspect ratio frames per second select a new frame rate or select original to use the original frame rate of the stream default original note when a new frame rate is specified, it is applied using "smooth frame rate conversion" note when the frame rate is converted, captions in the elementary stream are preserved bitrate mode select the desired bitrate mode cbr (constant bit rate) ensure that video streams occupy a certain number of bits per second when they are played back vbr (variable bitrate) varies the amount of output data per time segment network adaptive configures the bitrate of the transcoded channel according to the network conditions reported by the push output this is relevant when using push output on the transcoded channel and "encoder feedback" was enabled average bitrate (kbps) specify the average bitrate for the profile max bitrate (kbps) specify the maximum bitrate for the profile available only if the bitrate mode is set to vbr performance select the performance of the transcoding possible values range from ultra fast which provides the best quality while utilizing high cpu/gpu to slower which has the lowest quality but uses much less cpu/gpu default very fast advanced options copy gop from source select this checkbox if you want to maintain the source gop length (not structure) enabling this option will generate an i frame in the transcoded stream with the exact timestamp as in the source stream the copy gop from source option is only available when selecting the original option in the frames per second field if you want to change the source gop length specify the new gop length in the gop \[frames] parameter gop \[frames] specify the number of frames in a gop (group of pictures) default 60 gop settings closed – for a gop in which the previous pictures do not need data from the subsequent gop for bidirectional coding, select the closed checkbox (default) fixed – to always use the specified number of frames in the gop (as opposed to allowing the encoder to override), select the fixed checkbox (default) b frames specify the maximal number of consecutive b frames in the gop default 0 frame type specify the frame type – progressive or interlaced (mpeg2 only on sw transcoding) default progressive reference frames specify the number of frames that can be referenced for each frame default 2 hrd buffer length (seconds) specify the length of the hrd buffer in mpeg 2 tune the x264 tune options assign options to optimize for certain types of content film – intended for high bitrate/high quality movie content lower deblocking is used here animation – intended for cartoons, etc , where deblocking is boosted to compensate for larger, flat areas more reference frames are used grain – this should be used for material that is already grainy here, the grain won't be filtered out as much fast decode – disables cabac and the in loop deblocking filter to allow for faster decoding on devices with lower computational power zero latency – optimization for fast encoding and low latency streaming crf the constant rate factor (crf) is the default quality (and rate control) setting for x264 and x265 encoders you can set the values between 0 and 51, where lower values would result in better quality, at the expense of higher file sizes higher values mean more compression, but at some point you will notice the quality degradation max qp the qp (quantization) parameter controls how the compression rate ranging from 0 (no compression) and 51 (max compression) max qp controls the maximum value the encoder can set for qp for example, a low number will result in a lower compression rate causing the video to look better, however requiring a higher bitrate a higher max qp value may reduce the visual quality but results in a lower bitrate chroma subsampling converts the source chroma sub sampling (method for "compression" of raw images) to 4 4 4/ 4 2 2 / 4 2 0 as source – maintains the same chroma subsampling as in the source 4 4 4 is applicable for nvidia hevc codec or x264 high profile 4 2 2 is not supported on nvidia gpu 4 2 0 is supported on nvidia and x264 bit depth conversion of the 10 bit hdr color encoding source to 8 bpp this feature is enabled for the following configurations h 264 – encoder x264; encoding profile high 10 h 265 – encoder nvidia; encoding profile main 10 if the source is 10 bit, select one of the following as source – to maintain a 10 bit color encoding 8 bpp – to down convert the source to 8 bit per pixel if the source is already 8bpp, it does nothing profile configuration for audio – aac, opus, raw audio name enter a unique name for the profile bitrate specify the bitrate for the profile sampling rate you can convert the audio sampling rate from 44 1khz to 48khz and vice versa select one of the following options copy from source – if you do not wish to make any changes 44 1khz – to convert a 48khz audio stream to 44 1khz 48khz – to convert a 44 1khz audio stream to 48khz encoding profile (for aac) aac lc (default) aac low complexity the simplest and most widely used and supported profile he aacv1 aac high efficiency 1 this profile uses spectral band replication (sbr) to enhance the compression efficiency in the frequency domain he aacv2 aac high efficiency 2 couples sbr with parametric stereo (ps) to enhance the compression efficiency of stereo signals it is a standardized and improved version of the eaac+ codec