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• ffmpeg chains parameters and options while being used in a loop

  10 janvier 2024, par Simon Nazarenko

  I got a code that generates videos from scratch (got gifs, captions and audio). It works amazing when done once, however, when put in a loop and it should create more than 1 video it freezes being caused by memory leak. Upon investigation I realized that ffmpeg (v1.1.0) chains the loop iterations carrying the parameters and options from the first iteration to the second. It then breaks (overwrites) the first video and infinitely writes the second.

  


  This is my dependency

  


  const ffmpeg = require("fluent-ffmpeg")()
  .setFfprobePath(ffprobe.path)
  .setFfmpegPath(ffmpegInstaller.path)


  


  It looks like this

  


  async function convertGifToVideo(
  gifFile,
  audioFile,
  subtitlesFile,
  tempDirectory
) {
  return new Promise((resolve, reject) => {
    const outputFile = `${tempDirectory}/video_${Date.now()}.mp4`
    
    ffmpeg
      .input(gifFile)
      .inputFormat("gif")
      .inputOptions("-stream_loop -1")
      .input(audioFile)
      .outputOptions("-shortest")
      .outputOptions(`-vf subtitles=${subtitlesFile}`)
      .outputOptions("-report")
      .output(outputFile)
      .on("end", () => {
        console.log(`Combined ${gifFile} and ${audioFile} into ${outputFile}`)
        resolve(outputFile)
      })
      .on("error", (err, stdout, stderr) => {
        console.error("Error combining GIF and audio:", err)
        console.error("ffmpeg stdout:", stdout)
        console.error("ffmpeg stderr:", stderr)
        reject(err)
      })
      .run()
  })
}


  


  And it's called in a loop

  


  for (const key in script) {
    if (script.hasOwnProperty(key)) {
      ...stuff

      const videoFileName = await convertGifToVideo(
        gifFileName,
        audioFileName,
        subtitlesFileName,
        tempDirectory
      )
    }
  }


  


  Here is a piece of log from the first video generation

  


  


  ffmpeg started on 2024-01-10 at 02:58:52
Report written to "ffmpeg-20240110-025852.log"
Command line :
/home/simon/Documents/AFYTUBE/node_modules/@ffmpeg-installer/linux-x64/ffmpeg -f gif -stream_loop -1 -i ./temp/gif_funny_frogs.gif -i ./temp/funny_frogs.mp3 -y -shortest -vf "subtitles=./temp/funny_frogs.srt" -report ./temp/video_1704880732780.mp4

  


  


  Here is a piece of log from the second one

  


  


  /home/simon/Documents/AFYTUBE/node_modules/@ffmpeg-installer/linux-x64/ffmpeg -f gif -stream_loop -1 -i ./temp/gif_funny_frogs.gif -i ./temp/funny_frogs.mp3 -f gif -stream_loop -1 -i ./temp/gif_leg_exercises.gif -i ./temp/leg_exercises.mp3 -y -shortest -vf "subtitles=./temp/funny_frogs.srt" -report -shortest -vf "subtitles=./temp/leg_exercises.srt" -report ./temp/video_1704880732780.mp4 ./temp/video_1704880750879.mp4

  


  


  Any ideas what I am doing wrong ?

  


• What is a Cohort Report ? A Beginner’s Guide to Cohort Analysis

  3 janvier 2024, par Erin

  Handling your user data as a single mass of numbers is rarely conducive to figuring out meaningful patterns you can use to improve your marketing campaigns.

  A cohort report (or cohort analysis) can help you quickly break down that larger audience into sequential segments and contrast and compare based on various metrics. As such, it is a great tool for unlocking more granular trends and insights — for example, identifying patterns in engagement and conversions based on the date users first interacted with your site.

  In this guide, we explain the basics of the cohort report and the best way to set one up to get the most out of it.

  What is a cohort report ?

  In a cohort report, you divide a data set into groups based on certain criteria — typically a time-based cohort metric like first purchase date — and then analyse the data across those segments, looking for patterns.

  Date-based cohort analysis is the most common approach, often creating cohorts based on the day a user completed a particular action — signed up, purchased something or visited your website. Depending on the metric you choose to measure (like return visits), the cohort report might look something like this :

  

  Note that this is not a universal benchmark or anything of the sort. The above is a theoretical cohort analysis based on app users who downloaded the app, tracking and comparing the retention rates as the days go by. 

  The benchmarks will be drastically different depending on the metric you’re measuring and the basis for your cohorts. For example, if you’re measuring returning visitor rates among first-time visitors to your website, expect single-digit percentages even on the second day.

  Your industry will also greatly affect what you consider positive in a cohort report. For example, if you’re a subscription SaaS, you’d expect high continued usage rates over the first week. If you sell office supplies to companies, much less so.

  What is an example of a cohort ?

  As we just mentioned, a typical cohort analysis separates users or customers by the date they first interacted with your business — in this case, they downloaded your app. Within that larger analysis, the users who downloaded it on May 3 represent a single cohort.

  

  In this case, we’ve chosen behaviour and time — the app download day — to separate the user base into cohorts. That means every specific day denotes a specific cohort within the analysis.

  Diving deeper into an individual cohort may be a good idea for important holidays or promotional events like Black Friday.

  Of course, cohorts don’t have to be based on specific behaviour within certain periods. You can also create cohorts based on other dimensions :

  • Transactional data — revenue per user
  • Churn data — date of churn
  • Behavioural cohort — based on actions taken on your website, app or e-commerce store, like the number of sessions per user or specific product pages visited
  • Acquisition cohort — which channel referred the user or customer

  For more information on different cohort types, read our in-depth guide on cohort analysis.

  How to create a cohort report (and make sense of it)

  Matomo makes it easy to view and analyse different cohorts (without the privacy and legal implications of using Google Analytics).

  Here are a few different ways to set up a cohort report in Matomo, starting with our built-in cohorts report.

  Cohort reports

  With Matomo, cohort reports are automatically compiled based on the first visit date. The default metric is the percentage of returning visitors.

  

  Changing the settings allows you to create multiple variations of cohort analysis reports.

  Break down cohorts by different metrics

  The percentage of returning visits can be valuable if you’re trying to improve early engagement in a SaaS app onboarding process. But it’s far from your only option.

  You can also compare performance by conversion, revenue, bounce rate, actions per visit, average session duration or other metrics.

  

  Change the time and scope of your cohort analysis

  Splitting up cohorts by single days may be useless if you don’t have a high volume of users or visitors. If the average cohort size is only a few users, you won’t be able to identify reliable patterns. 

  Matomo lets you set any time period to create your cohort analysis report. Instead of the most recent days, you can create cohorts by week, month, year or custom date ranges. 

  

  Cohort sizes will depend on your customer base. Make sure each cohort is large enough to encapsulate all the customers in that cohort and not so small that you have insignificant cohorts of only a few customers. Choose a date range that gives you that without scaling it too far so you can’t identify any seasonal trends.

  Cohort analysis can be a great tool if you’ve recently changed your marketing, product offering or onboarding. Set the data range to weekly and look for any impact in conversions and revenue after the changes.

  Using the “compare to” feature, you can also do month-over-month, quarter-over-quarter or any custom date range comparisons. This approach can help you get a rough overview of your campaign’s long-term progress without doing any in-depth analysis.

  You can also use the same approach to compare different holiday seasons against each other.

  If you want to combine time cohorts with segmentation, you can run cohort reports for different subsets of visitors instead of all visitors. This can lead to actionable insights like adjusting weekend or specific seasonal promotions to improve conversion rates.

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  Easily create custom cohort reports beyond the time dimension

  If you want to split your audience into cohorts by focusing on something other than time, you will need to create a custom report and choose another dimension. In Matomo, you can choose from a wide range of cohort metrics, including referrers, e-commerce signals like viewed product or product category, form submissions and more.

  

  Then, you can create a simple table-based report with all the insights you need by choosing the metrics you want to see. For example, you could choose average visit duration, bounce rate and other usage metrics.

  

  If you want more revenue-focused insights, add metrics like conversions, add-to-cart and other e-commerce events.

  Custom reports make it easy to create cohort reports for almost any dimension. You can use any metric within demographic and behavioural analytics to create a cohort. (You can explore the complete list of our possible segmentation metrics.)

  We cover different types of custom reports (and ideas for specific marketing campaigns) in our guide on custom segmentation.

  Create your first cohort report and gain better insights into your visitors

  Cohort reports can help you identify trends and the impact of short-term marketing efforts like events and promotions.

  With Matomo cohort reports you have the power to create complex custom reports for various cohorts and segments. 

  If you’re looking for a powerful, easy-to-use web analytics solution that gives you 100% accurate data without compromising your users’ privacy, Matomo is a great fit. Get started with a 21-day free trial today. No credit card required. 

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• ffmpeg -i desktop Output file does not contain any stream [closed]

  29 novembre 2024, par Antonio

  I'm trying to screen record a remote Windows VM machine which I'm accessing through ssh. I'm executing this command ffmpeg -f gdigrab -framerate 30 -i desktop -t 00:00:10 output.mp4 which is returning the following error :

  


  ffmpeg version 7.1-essentials_build-www.gyan.dev Copyright (c) 2000-2024 the FFmpeg developers
  built with gcc 14.2.0 (Rev1, Built by MSYS2 project)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --en
able-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma --enable-zlib --enable-libsrt --enable-libss
h --enable-libzmq --enable-avisynth --enable-sdl2 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-lib
aom --enable-libopenjpeg --enable-libvpx --enable-mediafoundation --enable-libass --enable-libfreetype --enable-libfribidi --enabl
e-libharfbuzz --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-dxva2
--enable-d3d11va --enable-d3d12va --enable-ffnvcodec --enable-libvpl --enable-nvdec --enable-nvenc --enable-vaapi --enable-libgme
--enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libtheora --enable-libvo-amrwbenc --enable-libgsm --en
able-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-librubberband
  libavutil      59. 39.100 / 59. 39.100
  libavcodec     61. 19.100 / 61. 19.100
  libavformat    61.  7.100 / 61.  7.100
  libavdevice    61.  3.100 / 61.  3.100
  libavfilter    10.  4.100 / 10.  4.100
  libswscale      8.  3.100 /  8.  3.100
  libswresample   5.  3.100 /  5.  3.100
  libpostproc    58.  3.100 / 58.  3.100
[gdigrab @ 000001a87f3af600] Capturing whole desktop as 1024x768x32 at (0,0)
[gdigrab @ 000001a87f3af600] Failed to capture image (error 5)
[gdigrab @ 000001a87f3af600] Could not find codec parameters for stream 0 (Video: bmp, none, 754987 kb/s): unspecified size
Consider increasing the value for the 'analyzeduration' (0) and 'probesize' (5000000) options
Input #0, gdigrab, from 'desktop':
  Duration: N/A, bitrate: 754987 kb/s
  Stream #0:0: Video: bmp, none, 754987 kb/s, 30 fps, 1000k tbr, 1000k tbn
Output #0, mp4, to 'output.mp4':
[out#0/mp4 @ 000001a87f3aeec0] Output file does not contain any stream
Error opening output file output.mp4.
Error opening output files: Invalid argument


  


  If I take a remote desktop connection and use the same command, then it works perfectly.

  


  I've also tried running ffmpeg.exe -f lavfi -i color=c=black:s=800x600:r=30:d=60 out.mp4 which records something but it's just a black screen.

  


  Does anyone have any idea what could be happening ? I'm clueless at this point as I haven't been able to find more info online.