Recherche avancée

Sur d’autres sites (7097)

• Transcoding HEVC 4K HDR using ffmpeg and vaapi

  13 mai 2021, par P. Brand

  I am trying to transcode a 4K HEVC HDR video to a lower bitrate using ffmpeg and VAAPI hardware acceleration for my LG OLED television.

  



  I use the following file :
Video

  



  Using the following command :

  



  ffmpeg -init_hw_device vaapi=va:/dev/dri/renderD128 -hwaccel vaapi -hwaccel_output_format vaapi -hwaccel_device va -filter_hw_device va -i LG\ 4K\ HDR\ Demo\ -\ Daylight.mkv -map 0:0 -t 00:00:20 -c:v hevc_vaapi -sei hdr -qp:v 21 lg_vaapi.mkv


  



  But this file is not recognized as HDR on my TV.

  



  When using the libx265 encoder (which is off course much slower) it works fine :

  



  ffmpeg -i LG\ 4K\ HDR\ Demo\ -\ Daylight.mkv -t 00:00:20 -map 0:0 -c:v libx265 -preset medium -crf 18 -x265-params "colorprim=bt2020:colormatrix=bt2020nc:transfer=smpte2084:colormatrix=bt2020nc:hdr=1:info=1:repeat-headers=1:master-display=G(13250,34500)B(7500,3000)R(34000,16000)WP(15635,16450)L(11000000,40)" lg_libx265.mkv


  



  When comparing the output of mediainfo on both files I can see the following properties are not set for the video track :

  



  

  • Color range

  


  • Color primaries

  


  • Transfer characteristics

  


  



  mediainfo for vaapi encode :

  



  General
Unique ID                                : 168011494166392912924249315217763643529 
(0x7E65D636029A5354FE73998A5ED6B089)
Complete name                            : lg_vaapi.mkv
Format                                   : Matroska
Format version                           : Version 4
File size                                : 118 MiB
Duration                                 : 20 s 4 ms
Overall bit rate                         : 49.6 Mb/s
Writing application                      : Lavf58.20.100
Writing library                          : Lavf58.20.100
ErrorDetectionType                       : Per level 1

Video
ID                                       : 1
Format                                   : HEVC
Format/Info                              : High Efficiency Video Coding
Format profile                           : Main 10@L5@Main
HDR format                               : SMPTE ST 2086, HDR10 compatible
Codec ID                                 : V_MPEGH/ISO/HEVC
Duration                                 : 20 s 4 ms
Bit rate                                 : 48.6 Mb/s
Width                                    : 3 840 pixels
Height                                   : 2 160 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 59.940 (60000/1001) FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 10 bits
Bits/(Pixel*Frame)                       : 0.098
Stream size                              : 116 MiB (98%)
Writing library                          : Lavc58.35.100 hevc_vaapi
Default                                  : Yes
Forced                                   : No
Mastering display color primaries        : Display P3
Mastering display luminance              : min: 0.0040 cd/m2, max: 1100 cd/m2


  



  mediainfo for the libx265 encode :

  



  General
Unique ID                                : 261605749278874425324960669956061374077 (0xC4CF6F42FE952004772A02D5819DA67D)
Complete name                            : lg_libx265.mkv
Format                                   : Matroska
Format version                           : Version 4
File size                                : 155 MiB
Duration                                 : 47 s 715 ms
Overall bit rate                         : 27.3 Mb/s
Writing application                      : Lavf58.20.100
Writing library                          : Lavf58.20.100
ErrorDetectionType                       : Per level 1

Video
ID                                       : 1
Format                                   : HEVC
Format/Info                              : High Efficiency Video Coding
Format profile                           : Main 10@L5.1@Main
HDR format                               : SMPTE ST 2086, HDR10 compatible
Codec ID                                 : V_MPEGH/ISO/HEVC
Duration                                 : 47 s 715 ms
Bit rate                                 : 26.8 Mb/s
Width                                    : 3 840 pixels
Height                                   : 2 160 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 59.940 (60000/1001) FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 10 bits
Bits/(Pixel*Frame)                       : 0.054
Stream size                              : 152 MiB (98%)
Writing library                          : x265 2.8:[Linux][GCC 9.1.0][64 bit] 10bit
Encoding settings                        : cpuid=1111039 / frame-threads=3 / 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=3 / no-allow-non-conformance / repeat-headers / annexb / no-aud / 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=20 / lookahead-slices=8 / scenecut=40 / radl=0 / no-intra-refresh / ctu=64 / min-cu-size=8 / no-rect / no-amp / max-tu-size=32 / tu-inter-depth=1 / tu-intra-depth=1 / limit-tu=0 / rdoq-level=0 / dynamic-rd=0.00 / no-ssim-rd / signhide / no-tskip / nr-intra=0 / nr-inter=0 / no-constrained-intra / strong-intra-smoothing / max-merge=2 / limit-refs=3 / no-limit-modes / me=1 / subme=2 / merange=57 / temporal-mvp / weightp / no-weightb / no-analyze-src-pics / deblock=0:0 / sao / no-sao-non-deblock / rd=3 / 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=0.00 / no-rd-refine / no-lossless / cbqpoffs=0 / crqpoffs=0 / rc=crf / crf=18.0 / qcomp=0.60 / qpstep=4 / stats-write=0 / stats-read=0 / ipratio=1.40 / pbratio=1.30 / aq-mode=1 / 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=1 / overscan=0 / videoformat=5 / range=0 / colorprim=9 / transfer=16 / colormatrix=9 / chromaloc=0 / display-window=0 / master-display=G(13250,34500)B(7500,3000)R(34000,16000)WP(15635,16450)L(10000000,50) / max-cll=0,0 / min-luma=0 / max-luma=1023 / 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 / no-opt-cu-delta-qp / no-aq-motion / hdr / no-hdr-opt / no-dhdr10-opt / no-idr-recovery-sei / analysis-reuse-level=5 / scale-factor=0 / refine-intra=0 / refine-inter=0 / refine-mv=0 / no-limit-sao / ctu-info=0 / no-lowpass-dct / refine-mv-type=0 / copy-pic=1 / max-ausize-factor=1.0 / no-dynamic-refine / no-single-sei
Default                                  : Yes
Forced                                   : No
Color range                              : Limited
Color primaries                          : BT.2020
Transfer characteristics                 : PQ
Matrix coefficients                      : BT.2020 non-constant
Mastering display color primaries        : Display P3
Mastering display luminance              : min: 0.0040 cd/m2, max: 1100 cd/m2


  



  I suspect Color range, Color primaries and Transfer characteristics are necessary to make the file recognized as HDR by my TV. 
How can I add these properties to the VAAPI encoded file ?

  



  Edit :
This patch fixes the problem :
Patch

  


• HLS streaming always starts from the beginning in Android Browser

  20 août 2015, par Cesar Zhou

  Problem

  HLS streaming works well in iOS browser(real time mid-stream),

  But in most of Android browser, the streaming always starts from the beginning(First Ts file when streaming started).

  Reference

  • Android System：4.0,4.4,etc..

  • Detail for FFmpeg command : Pull RTMP streaming, then use segment to transfer that into TS splits.

    ffmpeg -re -i rtmp://ipaddress/live/streamname
-codec:a libfaac -b:a 96k -af volume=1 -ac 2 -ar 44100
-f segment
-segment_time 5
-segment_list_flags live
-segment_list /path/to/m3u8
-segment_format mpegts /path/to/ts

  • Detail for m3u8 file

    #EXTM3U
#EXT-X-VERSION:3
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-ALLOW-CACHE:NO
#EXT-X-TARGETDURATION:6
#EXTINF:5.000278,
file0000.ts
#EXTINF:5.013356,
file0001.ts4

  • HLS Player：Ckplayer + m3u8 plugins

  Help

  Does anyone else meet this problem ?

• Stream video content through Web API 2

  12 février 2016, par FaNIX

  I’m in the process of working out what the best way is going to be to do the following :

  I have a bunch of CCTV footage files (MP4 files, ranging from 4MB-50MB in size), which I want to make available through a web portal. My first thought was to stream the file through Web API, so I found the link below :

  http://www.strathweb.com/2013/01/asynchronously-streaming-video-with-asp-net-web-api/

  After implementing a sample project, I realised that the example was based on Web API 1, and not Web API 2.1, which is what I’m using. After doing some more research, I got the code to compile with WebAPI 2.1. I then realised that if I want to do streaming I cannot use MP4 files, there is a fair amount of technical detail behind this, so here is the thread :

  Best approach to real time http streaming to HTML5 video client

  It seems for this to work I need to encode my MP4 files to something like WebM, but that is going to take too much time. Icecast (http://icecast.org/), which is a streaming server, but I haven’t tried it out yet, again not sure if this is what I need to do.

  Now that I think of it, I actually don’t need live streaming, I just need to allow the client to play the video file through their browser, perhaps using HTML5 video element ? The thing is, my application needs to work on IOS as well, so I reckon that means I cant even encode my MP4 to FLV and just use flash.

  All I really need is to have all my video clips as thumbnails on a web page, and if the client clicks on one, it begins to play ASAP, without having to download the entire file. Think of the "Watch Trailer" feature on imdb.com. Simply just play a video file, thats really what I want. I don’t need LIVE streaming, which is what I think WebM is for ? Again, not sure.