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• Revision 5668dcc7b9 : Refactor dec_build_inter_predictors Refactor the loops in dec_build_inter_predi

  22 mars 2015, par Frank Galligan

  Changed Paths :
   Modify /vp9/decoder/vp9_decodeframe.c

  
  
  Refactor dec_build_inter_predictors

  Refactor the loops in dec_build_inter_predictors to try and decrease
  the number of instructions. Limited testing saw about 1% perf
  increase on x86 and about 0.67 % perf increase on Arm.

  Change-Id : I69cfe6335bb562fbaaebf43fb3f5c5a2a28882a2

• ffmpeg way to encode h265 video that allows fast-forward play without jumps

  27 octobre 2022, par SysHex

  Let me start of by saying that this issue presents itself on a Android headset, while running a Unity app with unity video player component that plays a video on it at 2 times the speed. Hence, the issue might be related to these components and not the video file itself.

  


  I have a library of video files with properties as I will describe further down this post.

  


  When I play these files at 2x the speed , the become extremelly jumpy to the point they can't be watched.

  


  I've played with configurations such as : min-keyint=30:keyint=30:scenecut=0:open-gop=0:lossless=1 but I have to be honest and state that I have almost no clue as to what they do. I've read the documentation and understand gop, I-Frames , and the need to exist reference frames for fast seek, and almost for sure Fast playing of the file (?! maybe not ?) , but don't know how to fine tune this.

  


  Maybe I'm missing out something completely and/or someone as any advice as to what I could try ?

  


  The goal is to play these files at 2x its speed, or possibly faster.

  


  Now for the details on the mpeg4 files :

  


  Video
ID                                       : 1
Format                                   : HEVC
Format/Info                              : High Efficiency Video Coding
Format profile                           : Main@L5@Main
Codec ID                                 : hev1
Codec ID/Info                            : High Efficiency Video Coding
Duration                                 : 15 min 0 s
Bit rate                                 : 6 578 kb/s
Width                                    : 3 840 pixels
Height                                   : 2 160 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 30.000 FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0 (Type 0)
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.026
Stream size                              : 706 MiB (98%)
Writing library                          : x265 3.5+37-07b011400:[Windows][GCC 11.2.0][64 bit] 8bit+10bit+12bit
Encoding settings                        : cpuid=1111039 / frame-threads=3 / numa-pools=8 / wpp / no-pmode / no-pme / no-psnr / no-ssim / log-level=2 / input-csp=1 / input-res=3840x2160 / interlace=0 / total-frames=0 / level-idc=0 / high-tier=1 / uhd-bd=0 / ref=4 / no-allow-non-conformance / no-repeat-headers / annexb / no-aud / no-eob / no-eos / no-hrd / info / hash=0 / no-temporal-layers / open-gop / min-keyint=25 / keyint=250 / gop-lookahead=0 / bframes=4 / b-adapt=2 / b-pyramid / bframe-bias=0 / rc-lookahead=25 / lookahead-slices=4 / scenecut=40 / no-hist-scenecut / radl=0 / no-splice / no-intra-refresh / ctu=64 / min-cu-size=8 / rect / no-amp / max-tu-size=32 / tu-inter-depth=1 / tu-intra-depth=1 / limit-tu=0 / rdoq-level=2 / dynamic-rd=0.00 / no-ssim-rd / signhide / no-tskip / nr-intra=0 / nr-inter=0 / no-constrained-intra / strong-intra-smoothing / max-merge=3 / limit-refs=3 / limit-modes / me=3 / subme=3 / merange=57 / temporal-mvp / no-frame-dup / no-hme / weightp / no-weightb / no-analyze-src-pics / deblock=0:0 / sao / no-sao-non-deblock / rd=4 / selective-sao=4 / no-early-skip / rskip / no-fast-intra / no-tskip-fast / no-cu-lossless / no-b-intra / no-splitrd-skip / rdpenalty=0 / psy-rd=2.00 / psy-rdoq=1.00 / no-rd-refine / no-lossless / cbqpoffs=0 / crqpoffs=0 / rc=crf / crf=20.0 / qcomp=0.60 / qpstep=4 / stats-write=0 / stats-read=0 / ipratio=1.40 / pbratio=1.30 / aq-mode=2 / aq-strength=1.00 / cutree / zone-count=0 / no-strict-cbr / qg-size=32 / no-rc-grain / qpmax=69 / qpmin=0 / no-const-vbv / sar=0 / overscan=0 / videoformat=5 / range=0 / colorprim=1 / transfer=1 / colormatrix=1 / chromaloc=1 / chromaloc-top=0 / chromaloc-bottom=0 / display-window=0 / cll=0,0 / min-luma=0 / max-luma=255 / log2-max-poc-lsb=8 / vui-timing-info / vui-hrd-info / slices=1 / no-opt-qp-pps / no-opt-ref-list-length-pps / no-multi-pass-opt-rps / scenecut-bias=0.05 / hist-threshold=0.03 / no-opt-cu-delta-qp / no-aq-motion / no-hdr10 / no-hdr10-opt / no-dhdr10-opt / no-idr-recovery-sei / analysis-reuse-level=0 / analysis-save-reuse-level=0 / analysis-load-reuse-level=0 / scale-factor=0 / refine-intra=0 / refine-inter=0 / refine-mv=1 / refine-ctu-distortion=0 / no-limit-sao / ctu-info=0 / no-lowpass-dct / refine-analysis-type=0 / copy-pic=1 / max-ausize-factor=1.0 / no-dynamic-refine / no-single-sei / no-hevc-aq / no-svt / no-field / qp-adaptation-range=1.00 / scenecut-aware-qp=0conformance-window-offsets / right=0 / bottom=0 / decoder-max-rate=0 / no-vbv-live-multi-pass
Language                                 : English
Color range                              : Limited
Color primaries                          : BT.709
Transfer characteristics                 : BT.709
Matrix coefficients                      : BT.709
Codec configuration box                  : hvcC

Audio
ID                                       : 2
Format                                   : AAC LC
Format/Info                              : Advanced Audio Codec Low Complexity
Codec ID                                 : mp4a-40-2
Duration                                 : 15 min 0 s
Source duration                          : 15 min 0 s
Source_Duration_LastFrame                : -12 ms
Bit rate mode                            : Constant
Bit rate                                 : 128 kb/s
Channel(s)                               : 2 channels
Channel layout                           : L R
Sampling rate                            : 48.0 kHz
Frame rate                               : 46.875 FPS (1024 SPF)
Compression mode                         : Lossy
Stream size                              : 13.8 MiB (2%)
Source stream size                       : 13.8 MiB (2%)
Default                                  : Yes
Alternate group                          : 1
mdhd_Duration                            : 900233



  


• How can I stream camera using ffmpeg and send over network using live555

  13 juin 2014, par sukesh venkat

  I am making a application for streaming webcam. I would like to use ffmpeg to capture camera, ffmpeg as encoder and live555 as server. I know I must implement DeviceSource.cpp in live555 to encapsulate the encoder to receive frame from ffmpeg.So can anyone provide me some tutorial or example about implementing.Thanks in advanced.