FFmpeg Technical Guide

Master FFmpeg for Professional Streaming

Command-line reference for encoding, transcoding, streaming, and format conversion. Real-world examples optimized for Shoutcast Net video and audio streaming infrastructure.

Updated November 2025 • 15 min read

FFmpeg video encoding and streaming architecture diagram

Install FFmpeg

FFmpeg is available for all major operating systems. Choose your platform:

Windows

Download:

https://ffmpeg.org/download.html

Extract to C:\ffmpeg

Add to PATH in System Environment Variables

macOS

Using Homebrew:

brew install ffmpeg

Verify:

ffmpeg -version

Linux

Ubuntu/Debian:

sudo apt update
sudo apt install ffmpeg

CentOS/RHEL:

sudo yum install ffmpeg

Understanding FFmpeg Command Structure

Basic Command Pattern:

ffmpeg [global_options] [input_options] -i input_file [output_options] output_file

Common Input Options:

  • -i - Input file or stream
  • -ss - Start time (seek)
  • -t - Duration
  • -f - Force input format

Common Output Options:

  • -c:v - Video codec
  • -c:a - Audio codec
  • -b:v - Video bitrate
  • -b:a - Audio bitrate

Video Encoding Examples

Basic Format Conversion

Convert any video to MP4 (H.264):

ffmpeg -i input.mov -c:v libx264 -c:a aac output.mp4

Quick conversion (copy streams if compatible):

ffmpeg -i input.avi -c copy output.mp4

Quality Control

High quality (CRF 18-23):

ffmpeg -i input.mp4 -c:v libx264 -preset slow -crf 18 -c:a aac -b:a 192k output.mp4

Balanced quality/size (CRF 23-28):

ffmpeg -i input.mp4 -c:v libx264 -preset medium -crf 23 -c:a aac -b:a 128k output.mp4

Fixed bitrate for streaming:

ffmpeg -i input.mp4 -c:v libx264 -b:v 5000k -maxrate 5000k -bufsize 10000k \
  -c:a aac -b:a 128k output.mp4

Resolution & Scaling

Resolution FFmpeg Command Use Case
1080p (Full HD) -vf scale=-2:1080 Desktop, high-quality streaming
720p (HD) -vf scale=-2:720 Standard streaming quality
480p (SD) -vf scale=-2:480 Mobile 4G, slower connections
360p (Low) -vf scale=-2:360 Mobile 3G, bandwidth limited

Example: Scale to 720p with quality preset:

ffmpeg -i input.mp4 -vf scale=-2:720 -c:v libx264 -preset fast -crf 23 \
  -c:a aac -b:a 128k output_720p.mp4

Audio Encoding & Transcoding

Audio Format Conversion

Convert to MP3:

ffmpeg -i input.wav -c:a libmp3lame -b:a 320k output.mp3

Convert to AAC (better quality):

ffmpeg -i input.wav -c:a aac -b:a 192k output.m4a

Extract audio from video:

ffmpeg -i input.mp4 -vn -c:a libmp3lame -b:a 192k audio_only.mp3

Audio Quality Presets for Shoutcast Net

Quality Level Bitrate Command Example Best For
High 320 kbps -b:a 320k Music streaming, DJ sets
Standard 192 kbps -b:a 192k Radio stations, podcasts
Medium 128 kbps -b:a 128k Voice content, talk radio
Low 64 kbps -b:a 64k Mobile, bandwidth limited

Audio Enhancement

Normalize audio volume:

ffmpeg -i input.mp3 -af "loudnorm=I=-16:TP=-1.5:LRA=11" -c:a libmp3lame -b:a 192k normalized.mp3

Remove silence from beginning/end:

ffmpeg -i input.mp3 -af "silenceremove=start_periods=1:start_duration=1:start_threshold=-60dB:\
  detection=peak,aformat=dblp,areverse,silenceremove=start_periods=1:start_duration=1:\
  start_threshold=-60dB:detection=peak,aformat=dblp,areverse" output.mp3

Add fade in/out:

ffmpeg -i input.mp3 -af "afade=t=in:ss=0:d=3,afade=t=out:st=27:d=3" output.mp3

Live Streaming to Shoutcast Net

FFmpeg RTMP streaming workflow diagram

Stream Video File to RTMP

Basic RTMP streaming:

ffmpeg -re -i input.mp4 -c:v libx264 -preset veryfast -b:v 3000k \
  -maxrate 3000k -bufsize 6000k -c:a aac -b:a 128k \
  -f flv rtmp://live.shoutcastnet.com/live/YOUR_STREAM_KEY

Stream with 720p encoding:

ffmpeg -re -i input.mp4 -vf scale=-2:720 -c:v libx264 -preset veryfast \
  -b:v 2500k -maxrate 2500k -bufsize 5000k -g 60 -keyint_min 60 \
  -c:a aac -b:a 128k -ar 44100 \
  -f flv rtmp://live.shoutcastnet.com/live/YOUR_STREAM_KEY

Secure RTMPS streaming (encrypted):

ffmpeg -re -i input.mp4 -c:v libx264 -preset veryfast -b:v 3000k \
  -c:a aac -b:a 128k \
  -f flv rtmps://live.shoutcastnet.com:443/live/YOUR_STREAM_KEY

Stream from Webcam/Desktop

Windows - Stream webcam:

ffmpeg -f dshow -i video="Your Webcam Name":audio="Your Microphone Name" \
  -c:v libx264 -preset veryfast -b:v 2500k -c:a aac -b:a 128k \
  -f flv rtmp://live.shoutcastnet.com/live/YOUR_STREAM_KEY

macOS - Stream webcam:

ffmpeg -f avfoundation -framerate 30 -i "0:0" \
  -c:v libx264 -preset veryfast -b:v 2500k -c:a aac -b:a 128k \
  -f flv rtmp://live.shoutcastnet.com/live/YOUR_STREAM_KEY

Linux - Stream webcam:

ffmpeg -f v4l2 -framerate 30 -video_size 1280x720 -i /dev/video0 \
  -f alsa -i hw:0 -c:v libx264 -preset veryfast -b:v 2500k \
  -c:a aac -b:a 128k \
  -f flv rtmp://live.shoutcastnet.com/live/YOUR_STREAM_KEY

RTMP Parameters Explained

  • -re - Read input at native frame rate (prevents sending too fast)
  • -g 60 - GOP size / keyframe interval (2 seconds at 30fps)
  • -preset veryfast - Encoding speed (veryfast, fast, medium, slow)
  • -maxrate - Maximum bitrate cap for CBR streaming
  • -bufsize - Rate control buffer (usually 2x maxrate)

HLS (HTTP Live Streaming) Creation

Single Quality HLS

Create HLS playlist and segments:

ffmpeg -i input.mp4 -c:v libx264 -c:a aac -b:v 3000k -b:a 128k \
  -f hls -hls_time 6 -hls_playlist_type vod -hls_segment_filename "segment%03d.ts" \
  playlist.m3u8

Output: Creates playlist.m3u8 + segment000.ts, segment001.ts, etc.

Multi-Bitrate Adaptive HLS

Create adaptive streaming with multiple qualities:

ffmpeg -i input.mp4 \
  -filter_complex \
  "[0:v]split=3[v1][v2][v3]; \
  [v1]scale=-2:360[v1out]; \
  [v2]scale=-2:720[v2out]; \
  [v3]scale=-2:1080[v3out]" \
  -map "[v1out]" -c:v:0 libx264 -b:v:0 800k -maxrate:v:0 856k -bufsize:v:0 1200k \
  -map "[v2out]" -c:v:1 libx264 -b:v:1 2800k -maxrate:v:1 2996k -bufsize:v:1 4200k \
  -map "[v3out]" -c:v:2 libx264 -b:v:2 5000k -maxrate:v:2 5350k -bufsize:v:2 7500k \
  -map a:0 -c:a:0 aac -b:a:0 96k -ar:a:0 44100 \
  -map a:0 -c:a:1 aac -b:a:1 128k -ar:a:1 44100 \
  -map a:0 -c:a:2 aac -b:a:2 192k -ar:a:2 44100 \
  -f hls -hls_time 6 -hls_playlist_type vod \
  -master_pl_name master.m3u8 \
  -var_stream_map "v:0,a:0 v:1,a:1 v:2,a:2" \
  -hls_segment_filename "stream_%v/segment%03d.ts" stream_%v.m3u8

Tip: This creates master.m3u8 with three quality levels (360p, 720p, 1080p). Players automatically switch based on viewer bandwidth.

Advanced FFmpeg Techniques

Video Editing

Cut video (no re-encoding):

ffmpeg -ss 00:01:30 -to 00:03:45 -i input.mp4 -c copy output.mp4

Trim with re-encoding:

ffmpeg -i input.mp4 -ss 00:00:10 -t 00:00:30 -c:v libx264 -c:a aac output.mp4

Concatenate multiple videos:

# Create file list.txt with:
# file 'video1.mp4'
# file 'video2.mp4'
# file 'video3.mp4'

ffmpeg -f concat -safe 0 -i list.txt -c copy output.mp4

Add watermark/logo overlay:

ffmpeg -i input.mp4 -i logo.png -filter_complex \
  "[1:v]scale=120:-1[logo];[0:v][logo]overlay=W-w-10:10" \
  -c:a copy output.mp4

Thumbnail Generation

Extract single frame at specific time:

ffmpeg -i input.mp4 -ss 00:00:05 -vframes 1 thumbnail.jpg

Generate thumbnails every 10 seconds:

ffmpeg -i input.mp4 -vf "fps=1/10" thumbnails/thumb%04d.jpg

Create thumbnail strip/sprite:

ffmpeg -i input.mp4 -vf "select='not(mod(n,100))',scale=160:90,tile=10x10" sprite.jpg

Performance Optimization

Hardware acceleration (NVIDIA):

ffmpeg -hwaccel cuda -i input.mp4 -c:v h264_nvenc -preset fast -b:v 5000k \
  -c:a aac -b:a 192k output.mp4

Multi-threaded encoding:

ffmpeg -i input.mp4 -c:v libx264 -threads 8 -preset fast output.mp4

Two-pass encoding (best quality/size ratio):

# Pass 1
ffmpeg -i input.mp4 -c:v libx264 -b:v 3000k -pass 1 -an -f null /dev/null

# Pass 2
ffmpeg -i input.mp4 -c:v libx264 -b:v 3000k -pass 2 -c:a aac -b:a 128k output.mp4

Audio-Only Streaming for Radio

FFmpeg audio streaming setup for internet radio

Stream Audio to Shoutcast Net

Stream MP3 to Icecast/Shoutcast:

ffmpeg -re -i music.mp3 -c:a libmp3lame -b:a 192k \
  -f mp3 icecast://source:PASSWORD@stream.shoutcastnet.com:8000/stream

Playlist loop for 24/7 radio:

ffmpeg -stream_loop -1 -re -i playlist.m3u -c:a libmp3lame -b:a 192k \
  -f mp3 icecast://source:PASSWORD@stream.shoutcastnet.com:8000/radio

Mix multiple audio sources:

ffmpeg -i music.mp3 -i voiceover.mp3 \
  -filter_complex "[0:a][1:a]amix=inputs=2:duration=shortest" \
  -c:a libmp3lame -b:a 192k output.mp3

Common Issues & Solutions

Problem: FFmpeg build missing required codec support.

Solution: Check available encoders with ffmpeg -encoders. Install full FFmpeg build with all codecs, not minimal version.

Alternative: Use different codec: -c:v libx264 instead of h264_nvenc

Causes: Network instability, bitrate too high, keyframe interval wrong.

Solutions:

  • Lower bitrate: Use -b:v 2000k instead of 5000k
  • Set proper keyframe: -g 60 for 2-second GOP at 30fps
  • Use CBR: -maxrate 2000k -bufsize 4000k
  • Faster preset: -preset veryfast instead of slow

Solution 1 - Fix A/V sync:

ffmpeg -i input.mp4 -c:v libx264 -c:a aac -async 1 output.mp4

Solution 2 - Audio delay adjustment:

ffmpeg -i input.mp4 -itsoffset 0.5 -i input.mp4 -map 0:v -map 1:a -c copy output.mp4

Solutions for faster encoding:

  • Use faster preset: -preset ultrafast or veryfast
  • Enable hardware acceleration: -hwaccel cuda (NVIDIA) or -hwaccel qsv (Intel)
  • Lower resolution: -vf scale=-2:720 instead of 1080p
  • Reduce quality: -crf 28 instead of 18
  • Use multi-threading: -threads 8

FFmpeg Quick Reference

Common Codecs

  • -c:v libx264 - H.264 video (universal)
  • -c:v libx265 - H.265/HEVC (better compression)
  • -c:v libvpx-vp9 - VP9 for WebM
  • -c:a aac - AAC audio (universal)
  • -c:a libmp3lame - MP3 audio
  • -c:a libopus - Opus (best quality)

Encoding Presets

  • ultrafast - Fastest, largest file
  • veryfast - Good for live streaming
  • fast - Balanced speed/quality
  • medium - Default, good balance
  • slow - Better quality, slower
  • veryslow - Best quality, very slow

Useful Filters

  • -vf scale=-2:720 - Resize to 720p
  • -vf crop=1280:720:0:0 - Crop video
  • -vf fps=30 - Change frame rate
  • -af volume=2.0 - Double volume
  • -af loudnorm - Normalize audio
  • -af afade=t=in:d=3 - Fade in 3 sec

Quality Settings

  • -crf 18 - High quality (18-23)
  • -crf 23 - Balanced (default)
  • -crf 28 - Lower quality/smaller
  • -b:v 5000k - Fixed video bitrate
  • -b:a 192k - Audio bitrate
  • -maxrate 5000k - Max bitrate cap

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