词条 | Nvidia NVENC |
释义 |
The encoder is supported in many streaming and recording programs, such as Wirecast, Open Broadcaster Software (OBS) and Bandicam, and also works with Share game capture, which is included in Nvidia's GeForce Experience software.[3][4][5] Consumer targeted GeForce graphics cards officially support no more than 2 simultaneously encoding video streams, regardless of the count of the cards installed, but this restriction can be circumvented on Linux and Windows systems by applying an unofficial patch to the drivers[6]. Professional cards support between 2 and 21 simultaneous streams per card, depending on card model and compression quality.[1] It is accompanied by NVDEC for video decoding in Nvidia's Video Codec SDK.[1] {{Anchor|DEM}}VersionsNVENC has undergone several hardware revisions since its introduction with the first Kepler GPU (GK104).[7] {{Anchor|1.0}}First generation, Kepler GK1xxThe first generation of NVENC, which is shared by all Kepler-based GPUs, supports H.264 high-profile (YUV420, I/P/B frames, CAVLC/CABAC), H.264 SVC Temporal Encode VCE, and Display Encode Mode (DEM). NVidia's documentation states a peak encoder throughput of 8× realtime at a resolution of 1920×1080 (where the baseline "1×" equals 30{{nbsp}}Hz). Actual throughput varies on the selected preset, user-controlled parameters and settings, and the GPU/memory clock frequencies. The published 8× rating is achievable with the NVENC high-performance preset, which sacrifices compression efficiency and quality for encoder throughput. The high-quality preset is considerably slower but produces fewer compression artifacts. {{Anchor|2.0}}Second generation, Maxwell GM107Introduced with the first-generation Maxwell architecture, second generation NVENC adds support for the high-performance HP444 profile (YUV4:4:4, predictive lossless encoding), and increases encoder throughput up to 16× realtime, which corresponds to about 1080p @ 480{{nbsp}}Hz with the high-performance preset.) Maxwell GM108 does not have NVENC hardware encoder support. {{Anchor|3.0}}Third generation, Maxwell GM20xIntroduced with the second-generation Maxwell architecture, third generation NVENC implements the video compression algorithm High Efficiency Video Coding (a.k.a. HEVC, H.265) and also increases the H.264 encoder's throughput to cover 4K-resolution at 60{{nbsp}}Hz (2160p60). However, it does not support B-frames for HEVC encoding (just I and P frames). The maximum NVENC HEVC coding tree unit (CU) size is 32 (the HEVC standard allows a maximum of 64), and its minimum CU size is 8. HEVC encoding also lacks Sample Adaptive Offset (SAO). Adaptive quantization, look-ahead rate control, adaptive B-frames (H.264 only) and adaptive GOP features were added with the release of Nvidia Video Codec SDK 7. [8] These features rely on CUDA cores for hardware acceleration. SDK 7 supports two forms of adaptive quantization; Spatial AQ (H.264 and HEVC) and Temporal AQ (H.264 only). Nvidia's consumer-grade (GeForce) cards are restricted to two simultaneous encoding jobs. Their professional Quadro cards do not have this restriction. {{Anchor|4.0}}Fourth generation, Pascal GP10xFourth generation NVENC implements HEVC Main10 10-bit hardware encoding. It also doubles the encoding performance of 4K H.264 & HEVC when compared to previous generation NVENC. It supports HEVC 8K, 4:4:4 chroma subsampling, lossless encoding, and sample adaptive offset (SAO). Nvidia Video Codec SDK 8 added Pascal exclusive Weighted Prediction feature (CUDA based). Weighted prediction is not supported if the encode session is configured with B frames (H.264). There is no B-Frame support for HEVC encoding, and the maximum CU size is 32×32. The NVIDIA GT 1030 and the Mobile Quadro P500 are GP108 chips that don't support the NVENC encoder. [https://developer.nvidia.com/video-encode-decode-gpu-support-matrix] {{Anchor|5.0}}Fifth generation, Volta GV10x{{Empty section|date=March 2018}}{{Anchor|6.0}}Sixth generation, Turing TU10x/TU11xSixth generation NVENC implements HEVC 8K encoding at 30FPS, HEVC B-Frames support and provides up to 25% bitrate savings for HEVC and up to 15% bitrate savings for H.264. Operating system supportThe Nvidia NVENC SIP core needs to be supported by the device driver. The driver provides one or more interfaces, (e.g. OpenMAX IL) to NVENC. The NVENC SIP core can only be accessed through the proprietary NVENC API (as opposed to the open-source VDPAU API). It is bundled with Nvidia's GeForce driver. NVENC is available for Windows and Linux operating systems.[1] The free and open-source nouveau device driver does not support Nvidia NVENC.[9] FFmpeg has supported NVENC since 2014,[10] and is supported in Nvidia drivers.[11]See also
References1. ^1 2 3 {{cite web |url=https://developer.nvidia.com/nvidia-video-codec-sdk |title=NVIDIA VIDEO CODEC SDK |website=NVIDIA Developer |publisher=Nvidia |accessdate=2017-11-12 }} 2. ^{{cite web|url=http://www.anandtech.com/show/7764/the-nvidia-geforce-gtx-750-ti-and-gtx-750-review-maxwell/2 |title=Maxwell’s Feature Set: Kepler Refined |publisher=AnandTech |date=2014-02-18}} 3. ^{{Cite web|url=http://www.geforce.com/geforce-experience/system-requirements|title=System Requirements for NVIDIA GeForce Experience {{!}} GeForce {{!}} GeForce|website=www.geforce.com|access-date=2016-08-17}} 4. ^{{Cite web|url=https://www.telestream.net/wirecast/tech-specs.htm|title=Wirecast Tech Specs|website=telestream.net|access-date=2017-12-19}} 5. ^{{Cite web|url=https://obsproject.com/|title=Open Broadcaster Software - Index|website=obsproject.com|access-date=2016-08-17}} 6. ^{{cite web |url=https://github.com/keylase/nvidia-patch |title=nvidia-patch |publisher=GitHub}} 7. ^{{cite web |url=http://on-demand.gputechconf.com/gtc/2015/video/S5613.html |title=S5613 - High-Performance Video Encoding Using NVIDIA GPUs |publisher=Nvidia}} 8. ^http://on-demand.gputechconf.com/gtc/2016/presentation/s6226-abhijit-patait-high-performance-video.pdf 9. ^{{cite web |url=http://nouveau.freedesktop.org/wiki/FeatureMatrix/ |title=Nouveau Feature Matrix |publisher=Freedesktop.org}} 10. ^{{cite web |url=http://ffmpeg.org/doxygen/trunk/nvenc_8c_source.html |title=nvenc.c H.264 hardware encoding using nvidia nvenc}} 11. ^{{cite web |url=http://www.nvidia.com/download/driverResults.aspx/109629/en-us|title=QUADRO DESKTOP/QUADRO NOTEBOOK DRIVER RELEASE 375}} External links
2 : Nvidia IP cores|Video acceleration |
随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识,基本涵盖了大多数领域的百科知识,是一部内容自由、开放的电子版国际百科全书。