Sur d’autres sites (8347)

• MP4Box / FFMPEG concat loses audio after first clip

  17 novembre 2017, par user1615343

  So I am certainly no expert when it comes to either of these tools, but I have a web-based project that’s executing commands on an Amazon Linux server to concatenate two video files that are uploaded.

  Both files are converted to mp4s first using FFMPEG, and those play perfectly in a browser after conversion :

  ffmpeg -i file1.mpg -c:v libx264 -crf 22 -c:a aac -strict -2 -movflags faststart file2.mp4

  Then, I attempt to combine these two resulting mp4s into a single mp4. I tried using FFMPEG to do this but to no avail. Switching to try MP4Box got me much closer : the videos are concatenated together, but the audio stops playing at the end of the first clip, and the second clip is silent.

  MP4Box -force-cat -keepsys -add file.mp4 -cat file2.mp4 out.mp4

  I’ve tried varying versions of the above command with no better results. Any input is greatly appreciated.

  EDIT : info on .mp4 files using

  ffmpeg -i file1.mp4 -i file2.mp4

  ffmpeg -i 1510189259715DogRunsintoGlassDoor_315a03a8e20acfc.mp4 -i
  1510189273549NewhouseMoonMoonneverseenstairsbeforefunnydog_285a03a8e6aab25.mp4

  ffmpeg version N-61041-g52a2138 Copyright (c) 2000-2014 the FFmpeg
  developers

  built on Mar 2 2014 05:45:04 with gcc 4.6 (Debian 4.6.3-1)

  configuration : —prefix=/root/ffmpeg-static/64bit
  —extra-cflags=’-I/root/ffmpeg-static/64bit/include -static’ —extra-ldflags=’-L/root/ffmpeg-static/64bit/lib -static’ —extra-libs=’-lxml2 -lexpat -lfreetype’ —enable-static —disable-shared —disable-ffserver —disable-doc —enable-bzlib —enable-zlib —enable-postproc —enable-runtime-cpudetect —enable-libx264 —enable-gpl —enable-libtheora —enable-libvorbis —enable-libmp3lame —enable-gray —enable-libass —enable-libfreetype —enable-libopenjpeg —enable-libspeex —enable-libvo-aacenc —enable-libvo-amrwbenc —enable-version3 —enable-libvpx

  libavutil 52. 66.100 / 52. 66.100

  libavcodec 55. 52.102 / 55. 52.102

  libavformat 55. 33.100 / 55. 33.100

  libavdevice 55. 10.100 / 55. 10.100

  libavfilter 4. 2.100 / 4. 2.100

  libswscale 2. 5.101 / 2. 5.101

  libswresample 0. 18.100 / 0. 18.100

  libpostproc 52. 3.100 / 52. 3.100

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from
  ’1510189259715DogRunsintoGlassDoor_315a03a8e20acfc.mp4’ :

  Metadata :

  major_brand : isom

  minor_version : 512

  compatible_brands : isomiso2avc1mp41

  encoder : Lavf55.33.100

  Duration : 00:00:04.92, start : 0.023220, bitrate : 634 kb/s

  Stream #0:0(und) : Video : h264 (High) (avc1 / 0x31637661), yuv420p,
  360x360 [SAR 1:1 DAR 1:1], 501 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc
  (default)

  Metadata :

  handler_name : VideoHandler

  Stream #0:1(und) : Audio : aac (mp4a / 0x6134706D), 44100 Hz, mono,
  fltp, 132 kb/s (default)

  Metadata :

  handler_name : SoundHandler

  Input #1, mov,mp4,m4a,3gp,3g2,mj2, from
  ’1510189273549NewhouseMoonMoonneverseenstairsbeforefunnydog_285a03a8e6aab25.mp4’ :

  Metadata :

  major_brand : isom

  minor_version : 512

  compatible_brands : isomiso2avc1mp41

  encoder : Lavf55.33.100

  Duration : 00:00:18.79, start : 0.023220, bitrate : 455 kb/s

  Stream #1:0(und) : Video : h264 (High) (avc1 / 0x31637661), yuv420p,
  362x360 [SAR 1:1 DAR 181:180], 320 kb/s, 29.94 fps, 29.94 tbr, 11976
  tbn, 59.88 tbc (default)

  Metadata :

  handler_name : VideoHandler

  Stream #1:1(eng) : Audio : aac (mp4a / 0x6134706D), 44100 Hz, stereo,
  fltp, 129 kb/s (default)

  Metadata :

  handler_name : SoundHandler

  At least one output file must be specified

• 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 Ruben

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

  


• What is Google Analytics data sampling and what’s so bad about it ?

  16 août 2019, par Joselyn Khor — Analytics Tips, Development
  What 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 : 

  1. If the selected sample size is too small, you won’t get a good representative of all the data. 
  2. 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