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Video d’abeille en portrait
14 mai 2011, par
Mis à jour : Février 2012
Langue : français
Type : Video
Autres articles (104)
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Encoding and processing into web-friendly formats
13 avril 2011, parMediaSPIP automatically converts uploaded files to internet-compatible formats.
Video files are encoded in MP4, Ogv and WebM (supported by HTML5) and MP4 (supported by Flash).
Audio files are encoded in MP3 and Ogg (supported by HTML5) and MP3 (supported by Flash).
Where possible, text is analyzed in order to retrieve the data needed for search engine detection, and then exported as a series of image files.
All uploaded files are stored online in their original format, so you can (...) -
Ajouter des informations spécifiques aux utilisateurs et autres modifications de comportement liées aux auteurs
12 avril 2011, parLa manière la plus simple d’ajouter des informations aux auteurs est d’installer le plugin Inscription3. Il permet également de modifier certains comportements liés aux utilisateurs (référez-vous à sa documentation pour plus d’informations).
Il est également possible d’ajouter des champs aux auteurs en installant les plugins champs extras 2 et Interface pour champs extras. -
Encodage et transformation en formats lisibles sur Internet
10 avril 2011MediaSPIP transforme et ré-encode les documents mis en ligne afin de les rendre lisibles sur Internet et automatiquement utilisables sans intervention du créateur de contenu.
Les vidéos sont automatiquement encodées dans les formats supportés par HTML5 : MP4, Ogv et WebM. La version "MP4" est également utilisée pour le lecteur flash de secours nécessaire aux anciens navigateurs.
Les documents audios sont également ré-encodés dans les deux formats utilisables par HTML5 :MP3 et Ogg. La version "MP3" (...)
Sur d’autres sites (9611)
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I have an application in flask where it streams a camera using ffmpeg, the problem is that I can not display the video from the camera using the GPU [closed]
17 janvier, par RubenI'll put you in context, I am using flask (python) to display a camera in the browser to stream it, for this I use the following Python code :


command = [
 'ffmpeg',
 '-loglevel', 'warning',
 '-rtsp_transport', 'tcp',
 '-i', self.config['url'],
 '-map', '0:v:0', # fuerzo que solo procese el video
 '-vf', f'fps={self.config["fps"]},scale=640:360:force_original_aspect_ratio=decrease',
 '-c:v', 'h264_nvenc', # especificamos que queremos tirar de la gpu de nvidia
 '-preset', 'p7', # ajusta para la maxima calidad/velocidad (p1 mas rapida pero peor calidad - p7 más lento pero mejor calidad)
 '-qp', self.config['quality'], # control de calidad del codificador (0 [mejor calidad] - 51 [peor calidad])
 '-pix_fmt', 'yuv444p', # se mete explicitamente el formato de pixeles
 '-color_range', 'pc',
 '-an', # desactiva el audio
 '-f', 'image2pipe',
 'pipe:1'
] 

self.process = subprocess.Popen(
 command,
 stdout=subprocess.PIPE,
 stderr=subprocess.PIPE,
 bufsize=10**8
)


The problem is that it does not display the video streaming, but it connects correctly to the camera.


On the other hand, It show me the following warnings, which may have something to do with the display, it's probably the second warning that has to do with the pixel format :


DEBUG :main:FFmpeg [camera1] : Guessed Channel Layout for Input Stream #0.1 : mono
DEBUG :main:FFmpeg [camera1] : [swscaler @ 0x560f70b78680] deprecated pixel format used, make sure you did set range correctly


The server has different encodes installed :


DEV.LS h264 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 (decoders : h264 h264_v4l2m2m h264_qsv h264_cuvid ) (encoders : libx264 libx264rgb h264_nvenc h264_omx h264_qsv h264_v4l2m2m h264_vaapi nvenc nvenc_h264 )


Y uso el h264_nvenc, tambien el servidor tiene soporte de aceleración de hardware con :


libavutil 56. 70.100 / 56. 70.100
libavcodec 58.134.100 / 58.134.100
libavformat 58. 76.100 / 58. 76.100
libavdevice 58. 13.100 / 58. 13.100
libavfilter 7.110.100 / 7.110.100
libswscale 5. 9.100 / 5. 9.100
libswresample 3. 9.100 / 3. 9.100
libpostproc 55. 9.100 / 55. 9.100
Hardware acceleration methods :
vdpau
cuda
vaapi
qsv
drm
opencl


Between them h264_nvenc uses cuda


I expand a little on the information it provides me when using h264_nvenc :


Encoder h264_nvenc [NVIDIA NVENC H.264 encoder]:
 General capabilities: dr1 delay hardware
 Threading capabilities: none
 Supported hardware devices: cuda cuda
 Supported pixel formats: yuv420p nv12 p010le yuv444p p016le yuv444p16le bgr0 rgb0 cuda
h264_nvenc AVOptions:
 -preset <int> E..V....... Set the encoding preset (from 0 to 18) (default p4)
 default 0 E..V.......
 slow 1 E..V....... hq 2 passes
 medium 2 E..V....... hq 1 pass
 fast 3 E..V....... hp 1 pass
 hp 4 E..V.......
 hq 5 E..V.......
 bd 6 E..V.......
 ll 7 E..V....... low latency
 llhq 8 E..V....... low latency hq
 llhp 9 E..V....... low latency hp
 lossless 10 E..V.......
 losslesshp 11 E..V.......
 p1 12 E..V....... fastest (lowest quality)
 p2 13 E..V....... faster (lower quality)
 p3 14 E..V....... fast (low quality)
 p4 15 E..V....... medium (default)
 p5 16 E..V....... slow (good quality)
 p6 17 E..V....... slower (better quality)
 p7 18 E..V....... slowest (best quality)
 -tune <int> E..V....... Set the encoding tuning info (from 1 to 4) (default hq)
 hq 1 E..V....... High quality
 ll 2 E..V....... Low latency
 ull 3 E..V....... Ultra low latency
 lossless 4 E..V....... Lossless
 -profile <int> E..V....... Set the encoding profile (from 0 to 3) (default main)
 baseline 0 E..V.......
 main 1 E..V.......
 high 2 E..V.......
 high444p 3 E..V.......
 -level <int> E..V....... Set the encoding level restriction (from 0 to 62) (default auto)
 auto 0 E..V.......
 1 10 E..V.......
 1.0 10 E..V.......
 1b 9 E..V.......
 1.0b 9 E..V.......
 1.1 11 E..V.......
 1.2 12 E..V.......
 1.3 13 E..V.......
 2 20 E..V.......
 2.0 20 E..V.......
 2.1 21 E..V.......
 2.2 22 E..V.......
 3 30 E..V.......
 3.0 30 E..V.......
 3.1 31 E..V.......
 3.2 32 E..V.......
 4 40 E..V.......
 4.0 40 E..V.......
 4.1 41 E..V.......
 4.2 42 E..V.......
 5 50 E..V.......
 5.0 50 E..V.......
 5.1 51 E..V.......
 5.2 52 E..V.......
 6.0 60 E..V.......
 6.1 61 E..V.......
 6.2 62 E..V.......
 -rc <int> E..V....... Override the preset rate-control (from -1 to INT_MAX) (default -1)
 constqp 0 E..V....... Constant QP mode
 vbr 1 E..V....... Variable bitrate mode
 cbr 2 E..V....... Constant bitrate mode
 vbr_minqp 8388612 E..V....... Variable bitrate mode with MinQP (deprecated)
 ll_2pass_quality 8388616 E..V....... Multi-pass optimized for image quality (deprecated)
 ll_2pass_size 8388624 E..V....... Multi-pass optimized for constant frame size (deprecated)
 vbr_2pass 8388640 E..V....... Multi-pass variable bitrate mode (deprecated)
 cbr_ld_hq 8388616 E..V....... Constant bitrate low delay high quality mode
 cbr_hq 8388624 E..V....... Constant bitrate high quality mode
 vbr_hq 8388640 E..V....... Variable bitrate high quality mode
 -rc-lookahead <int> E..V....... Number of frames to look ahead for rate-control (from 0 to INT_MAX) (default 0)
 -surfaces <int> E..V....... Number of concurrent surfaces (from 0 to 64) (default 0)
 -cbr <boolean> E..V....... Use cbr encoding mode (default false)
 -2pass <boolean> E..V....... Use 2pass encoding mode (default auto)
 -gpu <int> E..V....... Selects which NVENC capable GPU to use. First GPU is 0, second is 1, and so on. (from -2 to INT_MAX) (default any)
 any -1 E..V....... Pick the first device available
 list -2 E..V....... List the available devices
 -delay <int> E..V....... Delay frame output by the given amount of frames (from 0 to INT_MAX) (default INT_MAX)
 -no-scenecut <boolean> E..V....... When lookahead is enabled, set this to 1 to disable adaptive I-frame insertion at scene cuts (default false)
 -forced-idr <boolean> E..V....... If forcing keyframes, force them as IDR frames. (default false)
 -b_adapt <boolean> E..V....... When lookahead is enabled, set this to 0 to disable adaptive B-frame decision (default true)
 -spatial-aq <boolean> E..V....... set to 1 to enable Spatial AQ (default false)
 -spatial_aq <boolean> E..V....... set to 1 to enable Spatial AQ (default false)
 -temporal-aq <boolean> E..V....... set to 1 to enable Temporal AQ (default false)
 -temporal_aq <boolean> E..V....... set to 1 to enable Temporal AQ (default false)
 -zerolatency <boolean> E..V....... Set 1 to indicate zero latency operation (no reordering delay) (default false)
 -nonref_p <boolean> E..V....... Set this to 1 to enable automatic insertion of non-reference P-frames (default false)
 -strict_gop <boolean> E..V....... Set 1 to minimize GOP-to-GOP rate fluctuations (default false)
 -aq-strength <int> E..V....... When Spatial AQ is enabled, this field is used to specify AQ strength. AQ strength scale is from 1 (low) - 15 (aggressive) (from 1 to 15) (default 8)
 -cq <float> E..V....... Set target quality level (0 to 51, 0 means automatic) for constant quality mode in VBR rate control (from 0 to 51) (default 0)
 -aud <boolean> E..V....... Use access unit delimiters (default false)
 -bluray-compat <boolean> E..V....... Bluray compatibility workarounds (default false)
 -init_qpP <int> E..V....... Initial QP value for P frame (from -1 to 51) (default -1)
 -init_qpB <int> E..V....... Initial QP value for B frame (from -1 to 51) (default -1)
 -init_qpI <int> E..V....... Initial QP value for I frame (from -1 to 51) (default -1)
 -qp <int> E..V....... Constant quantization parameter rate control method (from -1 to 51) (default -1)
 -weighted_pred <int> E..V....... Set 1 to enable weighted prediction (from 0 to 1) (default 0)
 -coder <int> E..V....... Coder type (from -1 to 2) (default default)
 default -1 E..V.......
 auto 0 E..V.......
 cabac 1 E..V.......
 cavlc 2 E..V.......
 ac 1 E..V.......
 vlc 2 E..V.......
 -b_ref_mode <int> E..V....... Use B frames as references (from 0 to 2) (default disabled)
 disabled 0 E..V....... B frames will not be used for reference
 each 1 E..V....... Each B frame will be used for reference
 middle 2 E..V....... Only (number of B frames)/2 will be used for reference
 -a53cc <boolean> E..V....... Use A53 Closed Captions (if available) (default true)
 -dpb_size <int> E..V....... Specifies the DPB size used for encoding (0 means automatic) (from 0 to INT_MAX) (default 0)
 -multipass <int> E..V....... Set the multipass encoding (from 0 to 2) (default disabled)
 disabled 0 E..V....... Single Pass
 qres 1 E..V....... Two Pass encoding is enabled where first Pass is quarter resolution
 fullres 2 E..V....... Two Pass encoding is enabled where first Pass is full resolution
 -ldkfs <int> E..V....... Low delay key frame scale; Specifies the Scene Change frame size increase allowed in case of single frame VBV and CBR (from 0 to 255) (default 0)
</int></int></int></boolean></int></int></int></int></int></int></int></boolean></boolean></float></int></boolean></boolean></boolean></boolean></boolean></boolean></boolean></boolean></boolean></boolean></int></int></boolean></boolean></int></int></int></int></int></int></int>

If anyone has some idea or needs more information to help me, I would appreciate it.


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What is Google Analytics data sampling and what’s so bad about it ?
16 août 2019, par Joselyn Khor — Analytics Tips, DevelopmentWhat is Google Analytics data sampling, and what’s so bad about it ?
Google (2019) explains what data sampling is :
“In data analysis, sampling is the practice of analysing a subset of all data in order to uncover the meaningful information in the larger data set.”[1]
This is basically saying instead of analysing all of the data, there’s a threshold on how much data is analysed and any data after that will be an assumption based on patterns.
Google’s (2019) data sampling thresholds :
Ad-hoc queries of your data are subject to the following general thresholds for sampling :
[Google] Analytics Standard : 500k sessions at the property level for the date range you are using
[Google] Analytics 360 : 100M sessions at the view level for the date range you are using (para. 3) [2]This threshold is limiting because your data in GA may become more inaccurate as the traffic to your website increases.
Say you’re looking through all your traffic data from the last year and find you have 5 million page views. Only 500K of that 5 million is accurate ! The data for the remaining 4.5 million (90%) is an assumption based on the 500K sample size.
This is a key weapon Google uses to sell to large businesses. In order to increase that threshold for more accurate reporting, upgrading to premium Google Analytics 360 for approximately US$150,000 per year seems to be the only choice.
What’s so bad about data sampling ?
It’s unfair to say sampled data is to be disregarded completely. There is a calculation ensuring it is representative and can allow you to get good enough insights. However, we don’t encourage it as we don’t just want “good enough” data. We want the actual facts.
In a recent survey sent to Matomo customers, we found a large proportion of users switched from GA to Matomo due to the data sampling issue.
The two reasons why data sampling isn’t preferable :
- If the selected sample size is too small, you won’t get a good representative of all the data.
- The bigger your website grows, the more inaccurate your reports will become.
An example of why we don’t fully trust sampled data is, say you have an ecommerce store and see your GA revenue reports aren’t matching the actual sales data, due to data sampling. In GA you may be seeing revenue for the month as $1 million, instead of actual sales of $800K.
The sampling here has caused an inaccuracy that could have negative financial implications. What you get in the GA report is an estimated dollar figure rather than the actual sales. Making decisions based on inaccurate data can be costly in this case.
Another disadvantage to sampled data is that you might be missing out on opportunities you would’ve noticed if you were given a view of the whole. E.g. not being able to see real patterns occurring due to the data already being predicted.
By not getting a chance to see things as they are and only being able to jump to the conclusions and assumptions made by GA is risky. The bigger your business grows, the less you can risk making business decisions based on assumptions that could be inaccurate.
If you feel you could be missing out on opportunities because your GA data is sampled data, get 100% accurately reported data.
The benefits of 100% accurate data
Matomo doesn’t use data sampling on any of our products or plans. You get to see all of your data and not a sampled data set.
Data quality is necessary for high impact decision-making. It’s hard to make strategic changes if you don’t have confidence that your data is reliable and accurate.
Learn about how Matomo is a serious contender to Google Analytics 360.
Now you can import your Google Analytics data directly into your Matomo
If you’re wanting to make the switch to Matomo but worried about losing all your historic Google Analytics data, you can now import this directly into your Matomo with the Google Analytics Importer tool.
Take the challenge !Compare your Google Analytics data (sampled data) against your Matomo data, or if you don’t have Matomo data yet, sign up to our 30-day free trial and start tracking !
References :
[1 & 2] About data sampling. (2019). In Analytics Help About data sampling. Retrieved August 14, 2019, from https://support.google.com/analytics/answer/2637192
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Build Opencv3.1 with ffmpeg
10 mai 2018, par batumanI tried to build Opencv3.1 at Ubuntu16.04 with ffmpeg.
I follow the instructions how to install ffmpeg at here.According to this discussion ,I checked.
>> mediainfo ~/Desktop/grb_2.mp4
General
Complete name : /home/nyan/Desktop/grb_2.mp4
Format : MPEG-4
Format profile : Base Media
Codec ID : isom (isom/iso2/avc1/mp41)
File size : 445 KiB
Duration : 27s 862ms
Overall bit rate : 131 Kbps
Encoded date : UTC 1904-01-01 00:00:00
Tagged date : UTC 1904-01-01 00:00:00
Writing application : Lavf57.66.105
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L3
Format settings, CABAC : Yes
Format settings, ReFrames : 4 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 27s 862ms
Bit rate : 128 Kbps
Width : 720 pixels
Height : 480 pixels
Display aspect ratio : 4:3
Original display aspect ratio : 4:3
Frame rate mode : Constant
Frame rate : 29.970 (30000/1001) fps
Standard : NTSC
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.012
Stream size : 435 KiB (98%)
Writing library : x264 core 148
Encoding settings : cabac=1 / ref=3 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / lookahead_threads=2 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=crf / mbtree=1 / crf=23.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
Encoded date : UTC 1904-01-01 00:00:00
Tagged date : UTC 1904-01-01 00:00:00
ffmpeg -codecs | grep -i avc
ffmpeg version N-90982-gb995ec0 Copyright (c) 2000-2018 the FFmpeg developers
built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.9) 20160609
configuration: --prefix=/home/nyan/ffmpeg_build --enable-shared --extra-cflags=-I/home/nyan/ffmpeg_build/include --extra-ldflags=-L/home/nyan/ffmpeg_build/lib --extra-libs='-lpthread -lm' --bindir=/home/nyan/bin --enable-gpl --enable-libass --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-nonfree
libavutil 56. 18.100 / 56. 18.100
libavcodec 58. 19.100 / 58. 19.100
libavformat 58. 13.101 / 58. 13.101
libavdevice 58. 4.100 / 58. 4.100
libavfilter 7. 21.100 / 7. 21.100
libswscale 5. 2.100 / 5. 2.100
libswresample 3. 2.100 / 3. 2.100
libpostproc 55. 2.100 / 55. 2.100
DEV.LS h264 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 (decoders: h264 h264_v4l2m2m ) (encoders: libx264 libx264rgb h264_v4l2m2m h264_vaapi )
D.A.L. avc On2 Audio for Video Codec (decoders: on2avc )So my ffmpeg installation is ok.
When I cmake to my Opencv, I have set up to ffmpeg as
But when I make to compile, I have error as
make[2]: *** No rule to make target '/home/nyan/ffmpeg_build/lib/libavresample.a', needed by 'lib/libopencv_videoio.so.3.1.0'. Stop.
CMakeFiles/Makefile2:8709: recipe for target 'modules/videoio/CMakeFiles/opencv_videoio.dir/all' failed
make[1]: *** [modules/videoio/CMakeFiles/opencv_videoio.dir/all] Error 2
Makefile:160: recipe for target 'all' failed
make: *** [all] Error 2How can I fix the problem ?
I install libavresample manually and
sudo apt-get install libavresample-dev
[sudo] password for nyan:
Reading package lists... Done
Building dependency tree
Reading state information... Done
libavresample-dev is already the newest version (7:2.8.14-0ubuntu0.16.04.1).It is newest version.
EDIT:Actually libavresample at ffmpeg is deprecated already.
So I tried to install Opencv3.4.1 higher version.
Compile, build and installation are fine.
ButVideoCapture cap(0);does not read from the device.
So I checked ffmpeg at Opencv3.4.1 installation aspython -c "import cv2; print(cv2.getBuildInformation())" | grep -i ffmpegFFMMPEG IS NO. So build with ffmpeg is not successful even though there was no error at build for Opencv3.4.1.
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