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• Is stream-format in h264 related to camera provided stream or is it more like transport thing ?

  13 janvier 2023, par rafauu

  I've got camera that produces video stream in different formats. One of them is h264 encoded stream. I use dshow along with gstreamer to acquire this stream and process it with c++ and send it also via shared memory. My question is related specifically to field stream-format in gst caps. How do I know whether it is byte-stream or avc ? Is it tightly coupled to stream produced by camera or is it like transport thing that I set with gstreamer by my own ? I work with rather complicated commercial specific pipelines that I cannot share full here. When I set in my code gst_caps_set_simple (gstCaps, "stream-format", G_TYPE_STRING, "byte-stream", nullptr); it works but I am not 100% why so I want to clarify that.

  


  I've tried checking information about this specific camera with ffmpeg but I cannot get info about stream-format. Best I got is :
ffmpeg -f dshow -list_options true -i video="nameOfCamera"

  


  (...)
vcodec=h264  min s=128x96 fps=0.015625 max s=768x480 fps=29.97
vcodec=h264  min s=128x96 fps=0.015625 max s=768x576 fps=25
vcodec=h264  min s=128x96 fps=0.015625 max s=768x480 fps=29.97
vcodec=h264  min s=128x96 fps=0.015625 max s=768x576 fps=25
vcodec=h264  min s=128x96 fps=0.015625 max s=768x480 fps=29.97
vcodec=h264  min s=128x96 fps=0.015625 max s=768x576 fps=25
vcodec=h264  min s=128x96 fps=0.015625 max s=768x576 fps=25
(...)


  


• Trying to install ffmpeg with brew and I keep getting errors related to "dav1d_bottle_manifest"

  13 décembre 2022, par Jonathan Doe

  I am trying to do some basic DSP in python and in order to play some of my audio files I need to install ffmpeg on my computer.

  


  I am running a 2019 macbook pro.

  


  When I run brew intsall ffmpeg -d

  


  I get this on my terminal output

  


  rm: /usr/local/Homebrew/.git/TMP_FETCH_FAILURES: is a directory
rm: /usr/local/Homebrew/.git/TMP_FETCH_FAILURES: is a directory
Running `brew update --auto-update`...


  


  This auto update just runs forever with no updates of any kind. I'm not sure if it is broken or stuck or what.

  


  I try to manually run :

  


   brew update -d


  


  and the update stalls forever on this section :

  


  + [[ -f /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core/.git/FETCH_HEAD ]]
+ touch /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core/.git/FETCH_HEAD
+ [[ -z '' ]]
+ [[ 200 == \3\0\4 ]]
+ [[ -n '' ]]
+ local tmp_failure_file=/usr/local/Homebrew/Library/Taps/homebrew/homebrew-core/.git/TMP_FETCH_FAILURES
+ rm -f /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core/.git/TMP_FETCH_FAILURES
+ [[ -n '' ]]
+ git fetch --tags --force -q origin refs/heads/master:refs/remotes/origin/master


  


  I am having so many problems with brew any help would be appreciated.

  


• Seeking with ffmpeg options fails or causes delayed playback in Discord bot

  29 août 2022, par J Petersen

  My Discord bot allows users to play a song starting from a timestamp.

  


  The problem is that playback is delayed and audio plays faster and is jumbled if start times >= 30s are set.

  


  Results from testing different start times. Same URL, 30 second duration :

  


  





  


  


  


  


  


  



  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  


  Entered Start Time (s)	Playback Delay (s)	Song Playback Time (s)
  0	3	30
  30	10	22
  60	17	17
  120	31	2
  150	120	<1

  


  


  I am setting the start time using ffmpeg_options as suggested in this question.

  


  Does anyone understand why the audio playback is being delayed/jumbled ? How can I improve playback delay and allow users to start in the middle of a multi-chapter YouTube video ?

  


  Code :

  


  import discord
import youtube_dl
import asyncio


# Suppress noise about console usage from errors
youtube_dl.utils.bug_reports_message = lambda: ""


ytdl_format_options = {
    "format": "bestaudio/best",
    "outtmpl": "%(extractor)s-%(id)s-%(title)s.%(ext)s",
    "restrictfilenames": True,
    "noplaylist": False,
    "yesplaylist": True,
    "nocheckcertificate": True,
    "ignoreerrors": False,
    "logtostderr": False,
    "quiet": True,
    "no_warnings": True,
    "default_search": "auto",
    "source_address": "0.0.0.0",  # Bind to ipv4 since ipv6 addresses cause issues at certain times
}

ytdl = youtube_dl.YoutubeDL(ytdl_format_options)


class YTDLSource(discord.PCMVolumeTransformer):
    def __init__(self, source: discord.AudioSource, *, data: dict, volume: float = 0.5):
        super().__init__(source, volume)

        self.data = data

        self.title = data.get("title")
        self.url = data.get("url")

    @classmethod
    async def from_url(cls, url, *, loop=None, stream=False, timestamp = 0):
        ffmpeg_options = {
            "options": f"-vn -ss {timestamp}"}

        loop = loop or asyncio.get_event_loop()

        data = await loop.run_in_executor(None, lambda: ytdl.extract_info(url, download=not stream))
        if "entries" in data:
            # Takes the first item from a playlist
            data = data["entries"][0]

        filename = data["url"] if stream else ytdl.prepare_filename(data)
        return cls(discord.FFmpegPCMAudio(filename, **ffmpeg_options), data=data)


intents = discord.Intents.default()

bot = discord.Bot(intents=intents)

@bot.slash_command()
async def play(ctx, audio: discord.Option(), seconds: discord.Option(), timestamp: discord.Option()):
    channel = ctx.author.voice.channel
    voice = await channel.connect()
    player = await YTDLSource.from_url(audio, loop=bot.loop, stream=True, timestamp=int(timestamp))
    voice.play(player)
    await asyncio.sleep(int(seconds))
    await voice.disconnect()

token = token value
bot.run(token)