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• FFMPEG Concatenating videos with same 25fps results in output file with 3.554fps

  5 juin 2024, par Kendra Broom

  I created an AWS Lambda function in node.js 18 that is using a static, ver 7 build of FFmpeg located in a lambda layer. Unfortunately it's just the ffmpeg build and doesn't include ffprobe.

  


  I have an mp4 audio file in one S3 bucket and a wav audio file in a second S3 bucket. I'm uploading the output file to a third S3 bucket.

  


  Specs on the files (please let me know if any more info is needed)

  


  Audio :
wav, 13kbps, aac (LC), 6:28 duration

  


  Video :
mp4, 1280x720 resolution, 25 frame rate, h264 codec, 3:27 duration

  


  Goal :
Create blank video to fill in the duration gaps so the full audio is covered before and after the mp4 video (using timestamps and duration). Strip the mp4 audio and use the wav audio only. Output should be an mp4 video with the wav audio playing over it and blank video for 27 seconds (based on timestamp) until mp4 video plays for 3:27, and then blank video to cover the rest of the audio until 6:28.

  


  Actual Result :
An mp4 file with 3.554 frame rate and 10:06 duration.

  


  import { S3Client, GetObjectCommand, PutObjectCommand } from "@aws-sdk/client-s3";
import { createWriteStream, createReadStream, promises as fsPromises } from 'fs';
import { exec } from 'child_process';
import { promisify } from 'util';
import { basename } from 'path';

const execAsync = promisify(exec);

const s3 = new S3Client({ region: 'us-east-1' });

async function downloadFileFromS3(bucket, key, downloadPath) {
    const getObjectParams = { Bucket: bucket, Key: key };
    const command = new GetObjectCommand(getObjectParams);
    const { Body } = await s3.send(command);
    return new Promise((resolve, reject) => {
        const fileStream = createWriteStream(downloadPath);
        Body.pipe(fileStream);
        Body.on('error', reject);
        fileStream.on('finish', resolve);
    });
}

async function uploadFileToS3(bucket, key, filePath) {
    const fileStream = createReadStream(filePath);
    const uploadParams = { Bucket: bucket, Key: key, Body: fileStream };
    try {
        await s3.send(new PutObjectCommand(uploadParams));
        console.log(`File uploaded successfully to ${bucket}/${key}`);
    } catch (err) {
        console.error("Error uploading file: ", err);
        throw new Error('Failed to upload file to S3');
    }
}

function parseDuration(durationStr) {
    const parts = durationStr.split(':');
    return parseInt(parts[0]) * 3600 + parseInt(parts[1]) * 60 + parseFloat(parts[2]);
}

export async function handler(event) {
    const videoBucket = "video-interaction-content";
    const videoKey = event.videoKey;
    const audioBucket = "audio-call-recordings";
    const audioKey = event.audioKey;
    const outputBucket = "synched-audio-video";
    const outputKey = `combined_${basename(videoKey, '.mp4')}.mp4`;

    const audioStartSeconds = new Date(event.audioStart).getTime() / 1000;
    const videoStartSeconds = new Date(event.videoStart).getTime() / 1000;
    const audioDurationSeconds = event.audioDuration / 1000;
    const timeDifference = audioStartSeconds - videoStartSeconds;

    try {
        const videoPath = `/tmp/${basename(videoKey)}`;
        const audioPath = `/tmp/${basename(audioKey)}`;
        await downloadFileFromS3(videoBucket, videoKey, videoPath);
        await downloadFileFromS3(audioBucket, audioKey, audioPath);

        //Initialize file list with video
        let filelist = [`file '${videoPath}'`];
        let totalVideoDuration = 0; // Initialize total video duration

        // Create first blank video if needed
        if (timeDifference < 0) {
            const blankVideoDuration = Math.abs(timeDifference);
            const blankVideoPath = `/tmp/blank_video.mp4`;
            await execAsync(`/opt/bin/ffmpeg -f lavfi -i color=c=black:s=1280x720:r=25 -c:v libx264 -t ${blankVideoDuration} ${blankVideoPath}`);
            //Add first blank video first in file list
            filelist.unshift(`file '${blankVideoPath}'`);
            totalVideoDuration += blankVideoDuration;
            console.log(`First blank video created with duration: ${blankVideoDuration} seconds`);
        }
        
        const videoInfo = await execAsync(`/opt/bin/ffmpeg -i ${videoPath} -f null -`);
        const videoDurationMatch = videoInfo.stderr.match(/Duration: ([\d:.]+)/);
        const videoDuration = videoDurationMatch ? parseDuration(videoDurationMatch[1]) : 0;
        totalVideoDuration += videoDuration;

        // Calculate additional blank video duration
        const additionalBlankVideoDuration = audioDurationSeconds - totalVideoDuration;
        if (additionalBlankVideoDuration > 0) {
            const additionalBlankVideoPath = `/tmp/additional_blank_video.mp4`;
            await execAsync(`/opt/bin/ffmpeg -f lavfi -i color=c=black:s=1280x720:r=25 -c:v libx264 -t ${additionalBlankVideoDuration} ${additionalBlankVideoPath}`);
            //Add to the end of the file list
            filelist.push(`file '${additionalBlankVideoPath}'`);
            console.log(`Additional blank video created with duration: ${additionalBlankVideoDuration} seconds`);
        }

        // Create and write the file list to disk
        const concatFilePath = '/tmp/filelist.txt';
        await fsPromises.writeFile('/tmp/filelist.txt', filelist.join('\n'));

        const extendedVideoPath = `/tmp/extended_${basename(videoKey)}`;
        //await execAsync(`/opt/bin/ffmpeg -f concat -safe 0 -i /tmp/filelist.txt -c copy ${extendedVideoPath}`);
        
        // Use -vsync vfr to adjust frame timing without full re-encoding
        await execAsync(`/opt/bin/ffmpeg -f concat -safe 0 -i ${concatFilePath} -c copy -vsync vfr ${extendedVideoPath}`);

        const outputPath = `/tmp/output_${basename(videoKey, '.mp4')}.mp4`;
        //await execAsync(`/opt/bin/ffmpeg -i ${extendedVideoPath} -i ${audioPath} -map 0:v:0 -map 1:a:0 -c:v copy -c:a aac -b:a 192k -shortest ${outputPath}`);

        await execAsync(`/opt/bin/ffmpeg -i ${extendedVideoPath} -i ${audioPath} -map 0:v:0 -map 1:a:0 -c:v copy -c:a aac -b:a 192k -shortest -r 25 ${outputPath}`);
        console.log('Video and audio have been merged successfully');

        await uploadFileToS3(outputBucket, outputKey, outputPath);
        console.log('File upload complete.');

        return { statusCode: 200, body: JSON.stringify('Video and audio have been merged successfully.') };
    } catch (error) {
        console.error('Error in Lambda function:', error);
        return { statusCode: 500, body: JSON.stringify('Failed to process video and audio.') };
    }
}


  


  Attempts :
I've tried re-encoding the concatenated file but the lambda function times out. I hoped that by creating blank video with a 25fps and all the other specs from the original mp4, I wouldn't have to re-encode the concatenated file. Obviously something is wrong, though. In the commented out code you can see I tried specifying 25 or not, and also tried -vsync and no -vsync. I'm new to FFmpeg so all tips are appreciated !

  


• Revision c353da68aa : third_party/libwebm : pull from upstream Changes : b6de61a Adds support for simpl

  4 août 2015, par James Zern

  Changed Paths :
   Modify /third_party/libwebm/Android.mk

  
   Modify /third_party/libwebm/PATENTS.TXT

  
   Modify /third_party/libwebm/README.libvpx

  
   Modify /third_party/libwebm/mkvmuxer.cpp

  
   Modify /third_party/libwebm/mkvmuxer.hpp

  
   Modify /third_party/libwebm/mkvmuxerutil.cpp

  
   Modify /third_party/libwebm/mkvmuxerutil.hpp

  
   Modify /third_party/libwebm/mkvparser.cpp

  
   Modify /third_party/libwebm/mkvparser.hpp

  
   Modify /third_party/libwebm/webmids.hpp

  
  
  third_party/libwebm : pull from upstream

  Changes :
  b6de61a Adds support for simple tags
  75a6d2d sample_muxer : Don’t write huge files.
  cec1f85 mkvmuxer : remove unused timecode_scale variable
  8a61b40 Merge "mkvparser : Tiny whitespace fix."
  7affc5c clang-format re-run
  d6d04ac mkvmuxer : use generic Cluster::AddFrame
  4928b0b Merge "mkvmuxer : Write Block key frames correctly."
  c2e4a46 Merge "sample_muxer : Use AddGenericFrame to add frames."
  e97f296 mkvparser : Tiny whitespace fix.
  d66ba44 Merge "Add support to parse DisplayUnit."
  deb41c2 Add support to parse DisplayUnit.
  42e5660 Fix issues on EBML lacing block parsing
  fe1e9bb Fix block parsing to not allow frame_size = 0
  2cb6a28 Change assertions to checks when parsing TrackPositions
  d04580f Fixes issues on Block Group parsing
  c3550fd mkvmuxer : Write Block key frames correctly.
  5dd0e40 Merge "mkvmuxer : Set is_key to true for metadata blocks."
  8e96863 mkvmuxer : Set is_key to true for metadata blocks.
  a9e4819 sample_muxer : Use AddGenericFrame to add frames.
  5a3be73 Change assertions to checks when load CuePoints
  f99f3b2 mkvmuxerutil::EbmlDateElementSize : remove value param
  ff572b5 Frame::IsValid : fix track_number check
  b6311dc mkvmuxer : Refactor to remove a lot of duplicate code
  256cd02 Merge "mkvmuxer : DiscardPadding should be signed integer."
  16c8e78 mkvmuxer : s/frame/data in all AddFrame* functions.
  c5e511c mkvmuxer : DiscardPadding should be signed integer.
  4baaa2c Add framework build script : iosbuild.sh
  3d06eb1 PATENTS : fix a typo : constitutes -> constitute
  d3849c2 mkvparser : Dead code removal.
  f439e52 Change assertions to checks when preloading Cues
  d3a44cd Fix track transversal when listing Cues on sample
  c6255af Tweak .gitignore so git status is clean after checkout and
  build : - added missing underscore to sample_muxer - added cmake and make
  related files
  b5229c7 Makefile.unix : s/samplemuxer/sample_muxer/
  e3616a6 Add support to parse stereo mode, display width and display
  height in mkvparser
  a4b68f8 parser : Fix bug in Chapters::Atom::Parse()
  bab0a00 cmake : Set library and project name the proper way on Windows.
  feeb9b1 Set library name to match Windows expectations.
  b9a549b Fix CMakefile to generate libwebm.a
  b386aa5 Add CMakeLists.txt and msvc_runtime.cmake.
  b0f8a81 parser : Fix memory leak in Chapter parsing
  f06e152 mkvmuxer : Fix MoveCuesBeforeClustersHelper recursive call.
  27bb747 allow subtitle tracks with ContentEncodings
  623d182 DoLoadCluster : tolerate empty clusters
  1156da8 Update PATENTS to reflect s/VP8/WebM/g
  0d4cb40 mkvmuxerutil : Use rand() in MSVC builds.
  e12fff0 mkvmuxer : Overload WriteEbmlHeader for backward compatibility
  a321704 mkvmuxer : write correct DocTypeVersion
  574045e mkvmuxer : fix DiscardPadding
  8be6397 Include crop elements when calculating size of Video element
  8f2d1b3 mkvparser : fix DiscardPadding extraction
  1c36c24 mkvmuxer : fix style guide violations
  568504e Merge "UUIDs can have their high bit set"
  acf788b Add support for CropLeft, CropRight, CropTop and CropBottom
  elements.
  418188b Merge "muxer : codec_id is a mandatory element"
  07688c9 mkvmuxer : Reject frames if invalid track number is passed.
  2a63e47 muxer : codec_id is a mandatory element
  d13c017 UUIDs can have their high bit set

  Change-Id : Iba28acb1ff774349d03e565f2641ddea132cf1e7

• My journey to Coviu

  27 octobre 2015, par silvia

  My new startup just released our MVP – this is the story of what got me here.

  I love creating new applications that let people do their work better or in a manner that wasn’t possible before.

  My first such passion was as a student intern when I built a system for a building and loan association’s monthly customer magazine. The group I worked with was managing their advertiser contacts through a set of paper cards and I wrote a dBase based system (yes, that long ago) that would manage their customer relationships. They loved it – until it got replaced by an SAP system that cost 100 times what I cost them, had really poor UX, and only gave them half the functionality. It was a corporate system with ongoing support, which made all the difference to them.

  The story repeated itself with a CRM for my Uncle’s construction company, and with a resume and quotation management system for Accenture right after Uni, both of which I left behind when I decided to go into research.

  Even as a PhD student, I never lost sight of challenges that people were facing and wanted to develop technology to overcome problems. The aim of my PhD thesis was to prepare for the oncoming onslaught of audio and video on the Internet (yes, this was 1994 !) by developing algorithms to automatically extract and locate information in such files, which would enable users to structure, index and search such content.

  Many of the use cases that we explored are now part of products or continue to be challenges : finding music that matches your preferences, identifying music or video pieces e.g. to count ads on the radio or to mark copyright infringement, or the automated creation of video summaries such as trailers.

  

  This continued when I joined the CSIRO in Australia – I was working on segmenting speech into words or talk spurts since that would simplify captioning & subtitling, and on MPEG-7 which was a (slightly over-engineered) standard to structure metadata about audio and video.

  In 2001 I had the idea of replicating the Web for videos : i.e. creating hyperlinked and searchable video-only experiences. We called it “Annodex” for annotated and indexed video and it needed full-screen hyperlinked video in browsers – man were we ahead of our time ! It was my first step into standards, got several IETF RFCs to my name, and started my involvement with open codecs through Xiph.

  Around the time that YouTube was founded in 2006, I founded Vquence – originally a video search company for the Web, but pivoted to a video metadata mining company. Vquence still exists and continues to sell its data to channel partners, but it lacks the user impact that has always driven my work.

  As the video element started being developed for HTML5, I had to get involved. I contributed many use cases to the W3C, became a co-editor of the HTML5 spec and focused on video captioning with WebVTT while contracting to Mozilla and later to Google. We made huge progress and today the technology exists to publish video on the Web with captions, making the Web more inclusive for everybody. I contributed code to YouTube and Google Chrome, but was keen to make a bigger impact again.

  The opportunity came when a couple of former CSIRO colleagues who now worked for NICTA approached me to get me interested in addressing new use cases for video conferencing in the context of WebRTC. We worked on a kiosk-style solution to service delivery for large service organisations, particularly targeting government. The emerging WebRTC standard posed many technical challenges that we addressed by building rtc.io , by contributing to the standards, and registering bugs on the browsers.

  Fast-forward through the development of a few further custom solutions for customers in health and education and we are starting to see patterns of need emerge. The core learning that we’ve come away with is that to get things done, you have to go beyond “talking heads” in a video call. It’s not just about seeing the other person, but much more about having a shared view of the things that need to be worked on and a shared way of interacting with them. Also, we learnt that the things that are being worked on are quite varied and may include multiple input cameras, digital documents, Web pages, applications, device data, controls, forms.

  So we set out to build a solution that would enable productive remote collaboration to take place. It would need to provide an excellent user experience, it would need to be simple to work with, provide for the standard use cases out of the box, yet be architected to be extensible for specialised data sharing needs that we knew some of our customers had. It would need to be usable directly on Coviu.com, but also able to integrate with specialised applications that some of our customers were already using, such as the applications that they spend most of their time in (CRMs, practice management systems, learning management systems, team chat systems). It would need to require our customers to sign up, yet their clients to join a call without sign-up.

  Collaboration is a big problem. People are continuing to get more comfortable with technology and are less and less inclined to travel distances just to get a service done. In a country as large as Australia, where 12% of the population lives in rural and remote areas, people may not even be able to travel distances, particularly to receive or provide recurring or specialised services, or to achieve work/life balance. To make the world a global village, we need to be able to work together better remotely.

  The need for collaboration is being recognised by specialised Web applications already, such as the LiveShare feature of Invision for Designers, Codassium for pair programming, or the recently announced Dropbox Paper. Few go all the way to video – WebRTC is still regarded as a complicated feature to support.

  

  With Coviu, we’d like to offer a collaboration feature to every Web app. We now have a Web app that provides a modern and beautifully designed collaboration interface. To enable other Web apps to integrate it, we are now developing an API. Integration may entail customisation of the data sharing part of Coviu – something Coviu has been designed for. How to replicate the data and keep it consistent when people collaborate remotely – that is where Coviu makes a difference.

  We have started our journey and have just launched free signup to the Coviu base product, which allows individuals to own their own “room” (i.e. a fixed URL) in which to collaborate with others. A huge shout out goes to everyone in the Coviu team – a pretty amazing group of people – who have turned the app from an idea to reality. You are all awesome !

  With Coviu you can share and annotate :

  • images (show your mum photos of your last holidays, or get feedback on an architecture diagram from a customer),
  • pdf files (give a presentation remotely, or walk a customer through a contract),
  • whiteboards (brainstorm with a colleague), and
  • share an application window (watch a YouTube video together, or work through your task list with your colleagues).

  All of these are regarded as “shared documents” in Coviu and thus have zooming and annotations features and are listed in a document tray for ease of navigation.

  This is just the beginning of how we want to make working together online more productive. Give it a go and let us know what you think.

  http://coviu.com/