Version 3.4
New features
------------
Edge-aware quadtree partitioning to terminate CU depth recursion based on edge information. --rskip level 2 enables the feature and --rskip-edge-threshold denotes the minimum expected edge-density percentage within the CU, below which the recursion is skipped. Experimental feature.
Application-level feature --abr-ladder for automating efficient ABR ladder generation. Shows ~65% savings in the over-all turn-around time required for the generation of a typical Apple HLS ladder in Intel(R) Xeon(R) Platinum 8280 CPU @ 2.70GHz over a sequential ABR-ladder generation approach that leverages save-load architecture.
Enhancements to existing features
---------------------------------
Improved efficiency in 2-pass rate-control algorithm. The savings in the bitrate is ~1.72% with visual improvement in quality in the initial 1-2 secs.
Encoder enhancements
--------------------
Faster ARM64 encodes enabled by ASM contributions from Huawei. The speed-up over no-asm version for 1080p encodes @ medium preset is ~15% in a 16 core H/W.
Strict VBV conformance in zone encoding.
Bug fixes
---------
Multi-pass encode failures with --frame-dup.
Corrupted bitstreams with --hist-scenecut when input depth and internal bit-depth differ.
Incorrect analysis propagation in multi-level save-load architecture.
Failure in detecting NUMA packages installed in non-standard directories.
Version 3.3
New features
Adaptive frame duplication to identify and skip encoding of near-identical frames and signal the duplication info to the decoder via pic_struct SEI. frame-dup to enable frame duplication and --dup-threshold to set the threshold for frame similarity (optional).
Boundary aware quantization to cut off bits from frames following scene-cut. This leverages the inability of HVS to perceive fine details during scene changes and saves bits. --scenecut-aware-qp , --scenecut-window and --max-qp-delta to enable boundary aware frame quantization, to set window size (optional) and to set QP offset (optional).
Improved scene-cut detection using edge and chroma histograms. --hist-scenecut to enable the feature and --hist-threshold (optional) to provide threshold for determining scene cuts.
Enhancements to existing features
--hme-range to modify search range for HME levels L0, L1, and L2.
Improved performance of AQ mode 4 by reducing memory foot print.
Introduced --analysis-save-reuse-level and --analysis-load-reuse-level to de-couple reuse levels of --analysis-save and --analysis-load. Turnaround time of ABR encoding can be reduced by properly leveraging these options.
Encoder enhancements
Improved VBV lookahead to eliminate blocky artifacts in Intra frames coming towards end of the title.
API changes
New API function x265_encoder_reconfig_zone() to invoke zone reconfiguration dynamically.
Renamed --hdr to --hdr10. --hdr will be deprecated in the upcoming major release.
Renamed --hdr-opt to --hdr10-opt. --hdr-opt will be deprecated in the upcoming major release.
Additions to x265_param structure to support the newly added features and encoder enhancements.
Version 3.2
New features
1. 3-level hierarchical motion estimation using :option:`--hme` and :option:`--hme-search`.
2. New AQ mode (:option:`--aq-mode` 4) with variance and edge information.
3. :option:`selective-sao` to selectively enable SAO at slice level.
Enhancements to existing features
1. New implementation of :option:`--refine-mv` with 3 refinement levels.
Encoder enhancements
1. Improved quality in the frames following dark scenes in ABR mode.
API changes
1. Additions to x265_param structure to support the newly added features :option:`--hme`, :option:`--hme-search` and :option:`selective-sao`.
Bug fixes
1. Fixed encoder crash with :option:`--zonefile` during failures in encoder_open().
2. Fixed JSON11 build errors with HDR10+ on MacOS high sierra.
3. Signalling out of range scaling list data fixed.
4. Inconsistent output fix for 2-pass rate-control with cutree ON.
Known issues
1. Build dependency on changeset cf37911 of SVT-HEVC.
Version 3.1
New features
* x265 can invoke SVT-HEVC library for encoding through --svt.
* x265 can now accept interlaced inputs directly (no need to separate fields), and sends it to the encoder with proper fps and frame-size through --field.
* --fades can detect and handle fade-in regions. This option will force I-slice and initialize RC history for the brightest frame after fade-in.
API changes
* A new flag to signal MasterDisplayParams and maxCll/Fall separately
Encoder enhancements
* Improved the performance of inter-refine level 1 by skipping the evaluation of smaller CUs when the current block is decided as “skip” by the save mode.
* New AVX2 primitives to improve the performance of encodes that enable --ssim-rd.
* Improved performance in medium preset with negligible loss in quality.
Bug fixes
* Bug fixes for zones.
* Fixed wrap-around from MV structure overflow occurred around 8K pixels or over.
* Fixed issues in configuring cbQpOffset and crQpOffset for 444 input
* Fixed cutree offset computation in 2nd pass encodes.
Known issues
* AVX512 main12 asm disabling.
* Inconsistent output with 2-pass due to cutree offset sharing.
Version 3.0
New features
option:: ‘–dolby-vision-profile <integer|float>’ generates bitstreams confirming to the specified Dolby Vision profile. Currently profile 5, profile 8.1 and profile 8.2 enabled, Default 0 (disabled)
option:: ‘–dolby-vision-rpu’ File containing Dolby Vision RPU metadata. If given, x265’s Dolby Vision metadata parser will fill the RPU field of input pictures with the metadata
read from the file. The library will interleave access units with RPUs in the bitstream. Default NULL (disabled).
option:: ‘–zonefile <filename>’ specifies a text file which contains the boundaries of the zones where each of zones are configurable.
option:: ‘–qp-adaptation-range’ Delta-QP range by QP adaptation based on a psycho-visual model. Default 1.0.
option:: ‘–refine-ctu-distortion <0/1>’ store/normalize ctu distortion in analysis-save/load. Default 0.
Experimental feature option:: ‘–hevc-aq’ enables adaptive quantization
It scales the quantization step size according to the spatial activity of one coding unit relative to frame average spatial activity. This AQ method utilizes the minimum variance of sub-unit in each coding unit to represent the coding unit’s spatial complexity.
Encoder enhancements
Preset: change param defaults for veryslow and slower preset. Replace slower preset with defaults used in veryslow preset and change param defaults in veryslow preset as per experimental results.
AQ: change default AQ mode to auto-variance
Cutree offset reuse: restricted to analysis reuse-level 10 for analysis-save -> analysis-load
Tune: introduce –tune animation option which improves encode quality for animated content
Reuse CU depth for B frame and allow I, P frame to follow x265 depth decision
Bug fixes
RC: fix rowStat computation in const-vbv
Dynamic-refine: fix memory reset size.
Fix linking issue on non x86 platform
Encoder: Do not include CLL SEI message if empty
Fix build error in VMAF lib
Version 2.9
New features
1. Support for chunked encoding
:option:`--chunk-start and --chunk-end`
Frames preceding first frame of chunk in display order will be encoded, however, they will be discarded in the bitstream.
Frames following last frame of the chunk in display order will be used in taking lookahead decisions, but, they will not be encoded.
This feature can be enabled only in closed GOP structures. Default disabled.
2. Support for HDR10+ version 1 SEI messages.
Encoder enhancements
1. Create API function for allocating and freeing x265_analysis_data.
2. CEA 608/708 support: Read SEI messages from text file and encode it using userSEI message.
Bug fixes
1. Disable noise reduction when vbv is enabled.
2. Support minLuma and maxLuma values changed by the commandline.
Version 2.8
New features
1. :option:--asm avx512 used to enable AVX-512 in x265. Default disabled.
For 4K main10 high-quality encoding, we are seeing good gains; for other resolutions and presets, we don't recommend using this setting for now.
2. :option:--dynamic-refine dynamically switches between different inter refine levels. Default disabled.
It is recommended to use :option:--refine-intra 4' with dynamic refinement for a better trade-off between encode efficiency and performance than using static refinement.
3. :option:--single-sei
Encode SEI messages in a single NAL unit instead of multiple NAL units. Default disabled.
4. :option:--max-ausize-factor controls the maximum AU size defined in HEVC specification.
It represents the percentage of maximum AU size used. Default is 1.
5. VMAF (Video Multi-Method Assessment Fusion)
Added VMAF support for objective quality measurement of a video sequence.
Enable cmake option ENABLE_LIBVMAF to report per frame and aggregate VMAF score. The frame level VMAF score does not include temporal scores.
This is supported only on linux for now.
Encoder enhancements
1. Introduced refine-intra level 4 to improve quality.
2. Support for HLG-graded content and pic_struct in SEI message.
Bug Fixes
1. Fix 32 bit build error (using CMAKE GUI) in Linux.
2. Fix 32 bit build error for asm primitives.
3. Fix build error on mac OS.
4. Fix VBV Lookahead in analysis load to achieve target bitrate.
Version 2.7
New features
1. :option:--gop-lookahead can be used to extend the gop boundary(set by --keyint). The GOP will be extended, if a scene-cut frame is found within this many number of frames.
2. Support for RADL pictures added in x265.
:option:--radl can be used to decide number of RADL pictures preceding the IDR picture.
Encoder enhancements
1. Moved from YASM to NASM assembler. Supports NASM assembler version 2.13 and greater.
2. Enable analysis save and load in a single run. Introduces two new cli options --analysis-save <filename> and --analysis-load <filename>.
3. Comply to HDR10+ LLC specification.
4. Reduced x265 build time by more than 50% by re-factoring ipfilter.asm.
Bug fixes
1. Fixed inconsistent output issue in deblock filter and --const-vbv.
2. Fixed Mac OS build warnings.
3. Fixed inconsistency in pass-2 when weightp and cutree are enabled.
4. Fixed deadlock issue due to dropping of BREF frames, while forcing slice types through qp file.
Version 2.6
===========
New features
------------
1. x265 can now refine analysis from a previous HEVC encode (using options :option:`--refine-inter`, and :option:`--refine-intra`), or a previous AVC encode (using option :option:`--refine-mv-type`). The previous encode's information can be packaged using the *x265_analysis_data_t* data field available in the *x265_picture* object.
2. Basic support for segmented (or chunked) encoding added with :option:`--vbv-end` that can specify the status of CPB at the end of a segment. String this together with :option:`--vbv-init` to encode a title as chunks while maintaining VBV compliance!
3. :option:`--force-flush` can be used to trigger a premature flush of the encoder. This option is beneficial when input is known to be bursty, and may be at a rate slower than the encoder.
4. Experimental feature :option:`--lowpass-dct` that uses truncated DCT for transformation.
Encoder enhancements
--------------------
1. Slice-parallel mode gets a significant boost in performance, particularly in low-latency mode.
2. x265 now officially supported on VS2017.
3. x265 now supports all depths from mono0 to mono16 for Y4M format.
API changes
-----------
1. Options that modified PPS dynamically (:option:`--opt-qp-pps` and :option:`--opt-ref-list-length-pps`) are now disabled by default to enable users to save bits by not sending headers. If these options are enabled, headers have to be repeated for every GOP.
2. Rate-control and analysis parameters can dynamically be reconfigured simultaneously via the *x265_encoder_reconfig* API.
3. New API functions to extract intermediate information such as slice-type, scenecut information, reference frames, etc. are now available. This information may be beneficial to integrating applications that are attempting to perform content-adaptive encoding. Refer to documentation on *x265_get_slicetype_poc_and_scenecut*, and *x265_get_ref_frame_list* for more details and suggested usage.
4. A new API to pass supplemental CTU information to x265 to influence analysis decisions has been added. Refer to documentation on *x265_encoder_ctu_info* for more details.
Bug fixes
---------
1. Bug fixes when :option:`--slices` is used with VBV settings.
2. Minor memory leak fixed for HDR10+ builds, and default x265 when pools option is specified.
3. HDR10+ bug fix to remove dependence on poc counter to select meta-data information.
Encoder enhancements
--------------------
1. Improved grain handling with :option:`--tune` grain option by throttling VBV operations to limit QP jumps.
2. Frame threads are now decided based on number of threads specified in the :option:`--pools`, as opposed to the number of hardware threads available. The mapping was also adjusted to improve quality of the encodes with minimal impact to performance.
3. CSV logging feature (enabled by :option:`--csv`) is now part of the library; it was previously part of the x265 application. Applications that integrate libx265 can now extract frame level statistics for their encodes by exercising this option in the library.
4. Globals that track min and max CU sizes, number of slices, and other parameters have now been moved into instance-specific variables. Consequently, applications that invoke multiple instances of x265 library are no longer restricted to use the same settings for these parameter options across the multiple instances.
5. x265 can now generate a seprate library that exports the HDR10+ parsing API. Other libraries that wish to use this API may do so by linking against this library. Enable ENABLE_HDR10_PLUS in CMake options and build to generate this library.
6. SEA motion search receives a 10% performance boost from AVX2 optimization of its kernels.
7. The CSV log is now more elaborate with additional fields such as PU statistics, average-min-max luma and chroma values, etc. Refer to documentation of :option:`--csv` for details of all fields.
8. x86inc.asm cleaned-up for improved instruction handling.
API changes
-----------
1. New API x265_encoder_ctu_info() introduced to specify suggested partition sizes for various CTUs in a frame. To be used in conjunction with :option:`--ctu-info` to react to the specified partitions appropriately.
2. Rate-control statistics passed through the x265_picture object for an incoming frame are now used by the encoder.
3. Options to scale, reuse, and refine analysis for incoming analysis shared through the x265_analysis_data field in x265_picture for runs that use :option:`--analysis-reuse-mode` load; use options :option:`--scale`, :option:`--refine-mv`, :option:`--refine-inter`, and :option:`--refine-intra` to explore.
4. VBV now has a deterministic mode. Use :option:`--const-vbv` to exercise.
Bug fixes
---------
1. Several fixes for HDR10+ parsing code including incompatibility with user-specific SEI, removal of warnings, linking issues in linux, etc.
2. SEI messages for HDR10 repeated every keyint when HDR options (:option:`--hdr-opt`, :option:`--master-display`) specified.
===========
Encoder enhancements
--------------------
1. HDR10+ supported. Dynamic metadata may be either supplied as a bitstream via the userSEI field of x265_picture, or as a json jile that can be parsed by x265 and inserted into the bitstream; use :option:`--dhdr10-info` to specify json file name, and :option:`--dhdr10-opt` to enable optimization of inserting tone-map information only at IDR frames, or when the tone map information changes.
2. Lambda tables for 8, 10, and 12-bit encoding revised, resulting in significant enhancement to subjective visual quality.
3. Enhanced HDR10 encoding with HDR-specific QP optimzations for chroma, and luma planes of WCG content enabled; use :option:`--hdr-opt` to activate.
4. Ability to accept analysis information from other previous encodes (that may or may not be x265), and selectively reuse and refine analysis for encoding subsequent passes enabled with the :option:`--refine-level` option.
5. Slow and veryslow presets receive a 20% speed boost at iso-quality by enabling the :option:`--limit-tu` option.
6. The bitrate target for x265 can now be dynamically reconfigured via the reconfigure API.
7. Performance optimized SAO algorithm introduced via the :option:`--limit-sao` option; seeing 10% speed benefits at faster presets.
API changes
-----------
1. x265_reconfigure API now also accepts rate-control parameters for dynamic reconfiguration.
2. Several additions to data fields in x265_analysis to support :option:`--refine-level`: see x265.h for more details.
Bug fixes
---------
1. Avoid negative offsets in x265 lambda2 table with SAO enabled.
2. Fix mingw32 build error.
3. Seek now enabled for pipe input, in addition to file-based input
4. Fix issue of statically linking core-utils not working in linux.
5. Fix visual artifacts with :option:`--multi-pass-opt-distortion` with VBV.
6. Fix bufferFill stats reported in csv.
===========
Encoder enhancements
--------------------
1. New SSIM-based RD-cost computation for improved visual quality, and efficiency; use :option:`--ssim-rd` to exercise.
2. Multi-pass encoding can now share analysis information from prior passes (in addition to rate-control information) to improve performance and quality of subsequent passes; to your multi-pass command-lines that use the :option:`--pass` option, add :option:`--multi-pass-opt-distortion` to share distortion information, and :option:`--multi-pass-opt-analysis` to share other analysis information.
3. A dedicated thread pool for lookahead can now be specified with :option:`--lookahead-threads`.
4. option:`--dynamic-rd` dynamically increase analysis in areas where the bitrate is being capped by VBV; works for both CRF and ABR encodes with VBV settings.
5. The number of bits used to signal the delta-QP can be optimized with the :option:`--opt-cu-delta-qp` option; found to be useful in some scenarios for lower bitrate targets.
6. Experimental feature option:`--aq-motion` adds new QP offsets based on relative motion of a block with respect to the movement of the frame.
API changes
-----------
1. Reconfigure API now supports signalling new scaling lists.
2. x265 application's csv functionality now reports time (in milliseconds) taken to encode each frame.
3. :option:`--strict-cbr` enables stricter bitrate adherence by adding filler bits when achieved bitrate is lower than the target; earlier, it was only reacting when the achieved rate was higher.
4. :option:`--hdr` can be used to ensure that max-cll and max-fall values are always signaled (even if 0,0).
Bug fixes
---------
1. Fixed incorrect HW thread counting on MacOS platform.
2. Fixed scaling lists support for 4:4:4 videos.
3. Inconsistent output fix for :option:`--opt-qp-pss` by removing last slice's QP from cost calculation.
4. VTune profiling (enabled using ENABLE_VTUNE CMake option) now also works with 2017 VTune builds.
MASTER_SITES= site1 \
site2
style continuation lines to be simple repeated
MASTER_SITES+= site1
MASTER_SITES+= site2
lines. As previewed on tech-pkg. With thanks to rillig for fixing pkglint
accordingly.
Encoder enhancements
--------------------
1. Enhancements to TU selection algorithm with early-outs for improved speed; use :option:`--limit-tu` to exercise.
2. New motion search method SEA (Successive Elimination Algorithm) supported now as :option: `--me` 4
3. Bit-stream optimizations to improve fields in PPS and SPS for bit-rate savings through :option:`--[no-]opt-qp-pps`, :option:`--[no-]opt-ref-list-length-pps`, and :option:`--[no-]multi-pass-opt-rps`.
4. Enabled using VBV constraints when encoding without WPP.
5. All param options dumped in SEI packet in bitstream when info selected.
6. x265 now supports POWERPC-based systems. Several key functions also have optimized ALTIVEC kernels.
performance oriented, with heavy improvements for AVX2 capable platforms
(Haswell and later Intel CPUs) and work efficiency improvements for
multiple-socket machines.
* encoder: emit an Active Parameter Sets SEI in stream headers if interlaced
* encoder: give more warnings when features are automatically disabled
* api: allow --psy-rdoq values up to 50; it can be beneficial for film grain
* docs: improve --pmode documentation, the feature is fully functional
* analysis: do not allow top-skip and depth earlyout in --pmode with --rd 5/6
* asm: correct wrong index name
* docs: update preset table and various command line options
* fix rd=0,1
* analysis: fix for --rd 0, do not assume a CU is only inter or intra
* analysis: rect cost compare typo fix for pmode
* search: ensure RDOQ entropy state is always initialized for chroma intra
