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VIDEO_PROCESSING.md

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Video Processing Instructions

Adding Cover Image Intro/Outro with Crossfades

This adds a static cover image at the beginning and end of a video with smooth crossfade transitions.

Prerequisites

  • ffmpeg installed
  • Cover image matching video dimensions (e.g., 1280x720 for 720p video)
  • Source video file

Command

ffmpeg -y \
  -loop 1 -t 4 -framerate 30 -i "COVER_IMAGE.png" \
  -i "INPUT_VIDEO.mp4" \
  -loop 1 -t 4 -framerate 30 -i "COVER_IMAGE.png" \
  -filter_complex "[0:v]format=yuv420p,settb=AVTB[intro];[1:v]format=yuv420p,fps=30,settb=AVTB[main];[2:v]format=yuv420p,settb=AVTB[outro];[intro][main]xfade=transition=fade:duration=1:offset=3[v1];[v1][outro]xfade=transition=fade:duration=1:offset=VIDEO_DURATION_PLUS_3[vout];[1:a]adelay=3000|3000,apad=pad_dur=3[aout]" \
  -map "[vout]" -map "[aout]" \
  -c:v libx264 -preset medium -crf 18 \
  -c:a aac -b:a 192k \
  "OUTPUT_VIDEO.mp4"

Parameters to Adjust

  1. COVER_IMAGE.png - Path to your cover image
  2. INPUT_VIDEO.mp4 - Path to your source video
  3. OUTPUT_VIDEO.mp4 - Path for the output file
  4. VIDEO_DURATION_PLUS_3 - Original video duration in seconds + 3 (for the intro offset)
  5. framerate 30 - Match your video's frame rate
  6. duration=1 - Crossfade duration (1 second)
  7. offset=3 - When crossfade starts (3 seconds = after 3s of cover display)

Getting Video Duration

ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 INPUT_VIDEO.mp4

Example

For a video with duration 5386.254333 seconds:

ffmpeg -y \
  -loop 1 -t 4 -framerate 30 -i "/path/to/cover.png" \
  -i "episode010-viktortron.mp4" \
  -loop 1 -t 4 -framerate 30 -i "/path/to/cover.png" \
  -filter_complex "[0:v]format=yuv420p,settb=AVTB[intro];[1:v]format=yuv420p,fps=30,settb=AVTB[main];[2:v]format=yuv420p,settb=AVTB[outro];[intro][main]xfade=transition=fade:duration=1:offset=3[v1];[v1][outro]xfade=transition=fade:duration=1:offset=5389.254333[vout];[1:a]adelay=3000|3000,apad=pad_dur=3[aout]" \
  -map "[vout]" -map "[aout]" \
  -c:v libx264 -preset medium -crf 18 \
  -c:a aac -b:a 192k \
  "episode010-viktortron-with-covers.mp4"

Filter Explanation

  • -loop 1 -t 4 - Loop the image for 4 seconds (3s visible + 1s crossfade)
  • settb=AVTB - Normalize timebase to avoid xfade errors
  • xfade=transition=fade:duration=1:offset=3 - 1-second fade starting at 3 seconds
  • adelay=3000|3000 - Delay audio by 3 seconds (3000ms per channel)
  • apad=pad_dur=3 - Pad 3 seconds of silence at the end

Extracting Audio from Video

Check Source Audio Bitrate

First, check what bitrate the reference audio files use:

ffprobe -v error -show_entries stream=bit_rate -of default=noprint_wrappers=1 REFERENCE.mp3

Extract MP3 at Matching Quality

ffmpeg -y -i "INPUT_VIDEO.mp4" -vn -c:a libmp3lame -b:a 128k "OUTPUT.mp3"

Parameters

  • -vn - No video (audio only)
  • -c:a libmp3lame - Use LAME MP3 encoder
  • -b:a 128k - Bitrate (use 128k to match existing files in this project)

Example

ffmpeg -y -i "episode010-viktortron-with-covers.mp4" -vn -c:a libmp3lame -b:a 128k "episode010-viktortron-with-covers.mp3"

Quick Reference

Task Command
Get video duration ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 VIDEO.mp4
Get video dimensions ffprobe -v error -show_entries stream=width,height -of csv=s=x:p=0 VIDEO.mp4
Get video framerate ffprobe -v error -show_entries stream=r_frame_rate -of default=noprint_wrappers=1:nokey=1 VIDEO.mp4
Get audio bitrate ffprobe -v error -show_entries stream=bit_rate -of default=noprint_wrappers=1 AUDIO.mp3