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Podcasts von MP3 und Vorbis in OPUS transkodieren

Podcasts werden derzeit häufig im MP3-Format in Stereo mit 128-192 kbit/s ausgeliefert (etwas seltener findet man auch das datensparsamere OGG/Vorbis Format).

Bei Podcasts kann(!) jedoch ein datensparsameres Mono-Signal ausreichen

• und Opus ist (als Nachfolger von OGG/Vorbis) zur Zeit der effizienteste Codec in Bezug die

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OPML

OPML of podcasts. Often updates.

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Stefan's Podcast List #1

Some random podcasts ... In some random order ...

---

Politk & Gesellschaft

Ganz offen gesagt

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# To extract the sound from a video and save it as MP3:
ffmpeg -i <video.mp4> -vn <sound>.mp3

# To convert frames from a video or GIF into individual numbered images:
ffmpeg -i <video.mpg|video.gif> <frame_%d.png>

# To combine numbered images (frame_1.jpg, frame_2.jpg, etc) into a video or GIF:
ffmpeg -i <frame_%d.jpg> -f image2 <video.mpg|video.gif>

# To quickly extract a single frame from a video at time mm:ss and save it as a 128x128 resolution image:

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ffmpeg -re -i INPUT -acodec libmp3lame -ab 160k -ar 44100 -f rtp rtp://host:port

#list device audio & video inputs
ffmpeg -f avfoundation -list_devices true -i ""

#stream from device audio & video inputs to rtmp
ffmpeg -f avfoundation -framerate 30 -i "0:2" -vcodec libx264 -tune zerolatency -s 1440x900 -acodec libmp3lame -f flv -strict -1 rtmp://host:port

#stream from audio inputs ONLY to rtmp
ffmpeg -f avfoundation -framerate 30 -i ":2" -acodec libmp3lame -f flv -strict -1 rtmp://host:port/live/$stream_name

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PERSONAL COMMAND LINE

FFMPEG :

Single source

ffmpeg.exe -i "input with spaces.mkv" -map 0:0 -map 0:1 \
    -c:a eac3 -ab 128k -ac 2 \
    -c:v libx264 -preset:v veryfast -tune:v animation -profile:v high -level:v 4.1 -b:v 3000k -strict -2 \
    -x264-params ref=4:subme=8:me_range=16:trellis=1:threads=18:lookahead_threads=3:bframes=3:keyint=240:keyint_min=24:rc_lookahead=50:ratetol=1.0:cplxblur=20.0:qblur=0.5 \

-vf "subtitles='input with spaces.mkv':si=0:force_style='Outline=1,Shadow=0'" output.mp4

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Detect the audio file volume with ffmpeg.

Require tools

• ffmpeg: [Official site][1], [Download][2]

How to use

1. Download ffmpeg from [link][2]
2. Extract the ffmpeg.exe from zip package and copy to the directory contain the audio file
3. Copy the volumeDetect.bat into the folder. (Just make sure the bat file and ffmpeg.exe are in the same directory)
4. Doulbe click volumeDetect.bat and drag the file into the window.
5. Press enter and get the result.

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Encoding Video

Installing

Install FFmpeg with homebrew. You'll need to install it with a couple flags for webm and the AAC audio codec.

brew install ffmpeg --with-libvpx --with-libvorbis --with-fdk-aac --with-opus

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Install ffmpeg with ALL includes

brew install ffmpeg $(brew options ffmpeg | grep -vE '\s' | grep -- '--with-' | tr '\n' ' ')

Cut video from 00:00:43 sec to 00:00:58 sec (15 sec duration).
Resize it to 720p.
Max quality options, but small size.

MP4

With audio:

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FFMpeg to Icecast2 Streaming Samples

Examples usage of various codecs with FFMpeg.

Samples

• flac.sh : An Icecast Source Client
  • for Windows (Cygwin is required)
  • and macOS (brew install ffmpeg)
• another_examples.sh : Samples
• FFMpeg can push to Icecast2 in various formats: Opus/Vorbis/AAC/MP3