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• Lambda/ffmpeg timelapse generation - output zero bytes, can't debug ffmpeg

  25 août 2021, par GoOutside

  I am attempting to use an AWS Lambda FFMPEG layer to build a timelapse of static images in an S3 bucket. To begin, I am basing my project off of the tutorial located here.

  


  I can replicate the steps in the tutorial, so I know the FFMPEG layer is working in Lambda. I have replicated the FFMPEG commands on a standalone server, so I know they are correct.

  


  Here is my setup : I have two S3 buckets, lambda-source-bucket and lambda-destination-bucket. The contents of lambda-source-bucket are :

  


  1.jpg
2.jpg
3.jpg
4.jpg
5.jpg
6.jpg
7.jpg
files.txt


  


  The files.txt contains this :

  


  file 'https://lambda-source-bucket.s3.us-west-2.amazonaws.com/1.jpg'
file 'https://lambda-source-bucket.s3.us-west-2.amazonaws.com/2.jpg'
file 'https://lambda-source-bucket.s3.us-west-2.amazonaws.com/3.jpg'
file 'https://lambda-source-bucket.s3.us-west-2.amazonaws.com/4.jpg'
file 'https://lambda-source-bucket.s3.us-west-2.amazonaws.com/5.jpg'
file 'https://lambda-source-bucket.s3.us-west-2.amazonaws.com/6.jpg'
file 'https://lambda-source-bucket.s3.us-west-2.amazonaws.com/7.jpg'


  


  This is my Lambda function code (in Python) :

  


  import json
import os
import subprocess
import shlex
import boto3

S3_DESTINATION_BUCKET = "lambda-destination-bucket"
SIGNED_URL_TIMEOUT = 60

def lambda_handler(event, context):

    s3_source_bucket = event['Records'][0]['s3']['bucket']['name']
    s3_source_key = event['Records'][0]['s3']['object']['key']

    s3_source_basename = os.path.splitext(os.path.basename(s3_source_key))[0]
    s3_destination_filename = "timelapse.mp4"

    s3_client = boto3.client('s3')
    s3_source_signed_url = s3_client.generate_presigned_url('get_object',
        Params={'Bucket': s3_source_bucket, 'Key': s3_source_key},
        ExpiresIn=SIGNED_URL_TIMEOUT)

    ffmpeg_cmd = "/opt/bin/ffmpeg -y -r 24 -f concat -safe 0 -protocol_whitelist file,http,tcp,https,tls -I ""https://lambda-source-bucket.s3.us-west-2.amazonaws.com/files.txt"" -c copy -s 1024x576 -vcodec libx264 -"    
command1 = shlex.split(ffmpeg_cmd)
    p1 = subprocess.run(command1, stdout=subprocess.PIPE, stderr=subprocess.PIPE)

    resp = s3_client.put_object(Body=p1.stdout, Bucket=S3_DESTINATION_BUCKET, Key=s3_destination_filename)

    return {
        'statusCode': 200,
        'body': json.dumps('Processing complete successfully')
    }


  


  The trigger for the Lambda function is when a new files.txt file is added to lambda-source-bucket.

  


  So far I have been able to get the trigger to fire, the function supposedly runs without errors (in Cloudwatch), and the function creates a new timelapse.mp4 in the lambda-destination-bucket. But this file is 0 bytes. I see no FFMPEG errors in the Cloudwatch console, though I am not sure I know how to configure my Lambda function code to log FFMPEG errors.

  


  Also : if I'm going about this in a totally wrong way, I'd love to hear feedback. I'm guessing that the concat and files.txt method of looping through https:// is not the most efficient way to do this, but it's the only way I can figure this out so far.

  


  Any help is most sincerely and humbly appreciated.

  


• flutter : record a video that has same duration as animated webp

  2 mai 2020, par Chris

  what I'd like to do :
I would like to record a video using Flutter's CameraController that has the same duration as an animated webp. On top of my screen, the animated webp is playing and below there is a CameraPreview() widget that records whatever my camera catches. This recorded video's duration should be exact as long as the animated webp's duration.

  



  what I've tried so far :
Since Giphy offers not only a webp-version, but also an mp4-version, I downloaded the mp4 version and used ffmpeg to get the duration of that file. 
I then used a timer and called VideoController.stopVideoRecording() after this duration automatically after VideoController.startVideoRecording().

  



  what I'd expect to happen :
I'd expect this recorded video to be as long as the animated webp. Unfortunately, it's not.

  



  So, my question is :
Do you guys have any idea how I could manage to record a video with same duration as an animated webp ?

  



  Thanks :)

  


• How to keep the file size of a stream small and have manycam show a live picture ?

  6 juillet 2017, par P. Dee

  I am using this command

  ffmpeg -i "rtsp://184.72.239.149/vod/mp4:BigBuckBunny_175k.mov" "C:\wamp\www\streaming.mjpeg"

  to stream to "C :\wamp\www\streaming.mjpeg". Then I am using SimpleHTTPServer to create a web server for this folder.

  Then I am pointing ManyCam’s ip camera to the address of the file on the web server

  http://127.0.0.1:8000/streaming.mjpeg

  And select it in ManyCam.

  As a result ffmpeg creates a file that gets bigger and bigger and ManyCam shows an endless time-lapsed loop of what the camera records or recorded minutes ago.

  How to keep the file size small and have ManyCam show a live video feed ?