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• AWS Lambda execution time for FFMPEG transcoding

  4 janvier 2023, par FlamingMoe

  I'm using AWS Lambda for converting files from WEBM to MP4

  


  I'm using ffmpeg version 4.3.1-static https://johnvansickle.com/ffmpeg/ (I have done the following tests also with the ffmpeg in serverless AWS ffmpeg layer (that includes de 4.1.3), but results are even worse (about 25% slower)

  


  I'm using Node 10x as container.

  


  WEBM size   Time to convert.  Memory Lambda.  Memory used (as shown in log)

80Mb             ~44s              3008            410
40Mb             ~44s              3008            375

80Mb             ~70s              1024            321
40Mb             ~70s              1024            279


  


  All videos are 80s length. So as far as I can see, it does not matter the size of the WEBM, if the length of the video is the same, it takes the same to convert. So ffmpeg takes more time if the video length is higher, not if the file size is higher ... curious ;-)

  


  But in the other hand, I'm confused with Lambda memory. I know memory and CPU comes together in Lambda ... the more memory you choose, the more CPU is assigned.

  


  But...

  


  

  1. Why ffmpeg just take about 300/400Mb if it has more to run ?

  


  2. How can I tell ffmpeg to use more memory ?

  


  3. Is there any option to accelerate the process in Lambda ?

  


  


  Btw, In all tests, all ffmpeg are the same, and

  


  cpu-used paramenter)

  


  

  • I added to ffmpeg parameters cpu-used=100, and it does not matter at all if I put cpu-used=5 ... times are the same, so I guess that parameter is useless (i don't know why)

  


  


  threads parameter)

  


  

  • Also I did some tests with "threads" parameters, but it's useless also.

  


  


  I know it's not a good comparison, but same files takes about 5 seconds to be converted in a simple dedicated server (8 vCores and 8GB RAM in OVH Centos VPS).

  


  Btw, Amazon Elastic Transcoder is not an option :
a) it's extremely more expensive
b) it has just his profiles to convert, and my ffmpeg commands are very complex (watermarks, effects, etc ...)

  


• rtmp audio out of sync, http works fine

  21 janvier 2014, par marca

  We have encoded and distributed videos for some years now, using FFMPEG to produce h.264/mp4 files that have been working great for us. We have been using HTML mode and fall-backed to flash for browsers that does not support it natively using flowplayer.

  We use cloudfront to serve our files from a s3 bucket and have been using http progressive streaming.

  Recently we started distribute the files in flashmode over rtmp instead, using a cloudfront streaming distribution pointing to the same amazon s3 bucket.

  All good for some weeks, until yesterday when we notice a couple of files with audio sync issues in rtmp mode.
  The same file have no sync problems in flash with direct url to file.

  What can be the case ?

  Not working when streamed via RTMP, but file work with http streaming/progressive.
  You see the sync issue 15 sec's into the video.
  rtmp ://s2xe2avk54qztf.cloudfront.net:1935/cfx/st/mp4:95fvOY255bdPspO3z6tEvGi3Em7/default.mp4
  http://media.shootitlive.com/95fvOY255bdPspO3z6tEvGi3Em7/default.mp4

  Another file that have no sync issue at all.
  rtmp ://s2xe2avk54qztf.cloudfront.net:1935/cfx/st/mp4:P4EuH2TZxfV6BvpupP6dxrrs7gD/default.mp4
  http://media.shootitlive.com/P4EuH2TZxfV6BvpupP6dxrrs7gD/default.mp4

  Both files have the same format for video and audio and have been encoded the exact same way with ffmpeg. It's not player related as we see the audio sync issue on several players and when playing stream in VLC.

• Need help to create a queue system with a discord.py bot

  19 août 2024, par Zamv

  im trying to create a bot with discord.py, i'll start saying that the bot is for personal use so please don't point out that i shouldn't use ydl in the comments, ty :
Also, im a beginner, so please tell me what I can improve and any errors there are, I will be happy to listen.
That said, i've been stuck on trying to create this queue system for songs for the past 3 days, the bot was working perfectly fine and played some urls before i implemented the play_next function, now it doesn't even play the first song, even if it sends confirmation messages both in the terminal that in the discord channel, i know that the code might be a little confusing, but please i really need to know how to make this work

  


  i wrote two main functions : "play_next" to play the next song in the queue and "play", the main command.
Here is my play_next function :

  


  async def play_next(self,ctx):
        if not ctx.voice_client.is_playing: #(don't know if this is correct as I also check if the bot isn't                     playing anything in the play function)
            
            if self.song.queue: 
                next_song = self.song_queue.pop(0) #deleting the first element of the queue, so if we have (song_0, song_1 and song_2) the bot should delete (song_0) making in fact song_1 the "next" song_0
                try:
                    ctx.voice_client.play(discord.FFmpegPCMAudio(next_song), 
                                          after=lambda e: self.bot.loop.create_task(self.play_next(ctx))) #Not gonna lie here, i asked chat gpt for this line, it should make the bot automatically play the next song one after another, correct me if I am wrong

#this is not important
                    embed = discord.Embed(
                        title="Song",
                        description=f"Now playing {next_song}",
                        color = 0x1DB954
                    )
                    await ctx.send(embed=embed)
                except Exception as e:
                    print(f"Error playing the next song: {e}")

            else:
                await ctx.voice_client.disconnect()  # disconnecting from the voice channel if the queue is empty
                print("Disconnected from the voice channel as the queue is empty.")


  


  I think that the main problem of my bot is the play_next function, but here it is my "play" function :

  


      @commands.command(pass_context=True)
    async def play(self, ctx, url: str):  
        if ctx.author.voice:  # first checking if the user is in a voice channel
            if not ctx.voice_client: #then checking if the bot is already connected to a voice channel
                channel = ctx.message.author.voice.channel 
                try:
                    await channel.connect()  #then joining
                    print("I joined the voice channel!")
                except Exception as e:
                    print(f"Failed to connect to the voice channel: {e}")
                    return

            song_path = f"song_{self.song_index}.mp3" #note, im using cogs, i declared self.song_index with the value of 0 
            self.song_index += 1 #i thought that this was the easiest way of creating a new file for each song

            ydl_opts = {
                'format': 'bestaudio/best',
                'postprocesors': [{
                    'key': 'FFmpegExtractAudio',
                    'preferredcodec': 'mp3',
                    'preferredquality': '192',
                }],
                'outtmpl': song_path
            }
            try:
                with youtube_dl.YoutubeDL(ydl_opts) as ydl:
                    print("Starting download...")
                    ydl.download([url]) #this is where it should download the song provided by the url
                    print("Download finished.")
            except Exception as e:
                await ctx.send(f"Failed to download the song: {e}")
                return

#i think that the next two if statements are the main threats
            if os.path.exists(song_path): #if there is atleast 1 song in the queue
                self.song_queue.append(song_path) #append the next one
                embed = discord.Embed(
                    title="Added to Queue!",
                    description = f"{url} has been added to the queue.",
                    color=0x33ff33
                )
                await ctx.send(embed=embed)


                if not ctx.voice_client.is_playing(): #checking if the bot is already playing something, don't know if i should put this if statement here
                    print("Starting playback...")
                    await self.play_next(ctx) #if nothing is playing, then the bot should play the next song



            else:
                await ctx.send("Failed to download or find the audio file.")

        else:
            embed = discord.Embed(
                title="❌You must be in a voice channel",
                color=0xff6666
            )
            await ctx.send(embed=embed)


  


  thanks in advance, i will try to read and answer any questions as soon as possible