ffmpeg-encoder-check

# FFmpeg Encoder Availability Check ## Purpose Before writing video encoding scripts, always verify which H.264 encoders are available in your FFmpeg installation. This prevents failures from library version mismatches, particularly with libopenh264. ## Instructions ### Step 1: Probe Available Encoders Run the following command to check available H.264 encoders: ```bash ffmpeg -encoders 2>/dev/null | grep h264 ``` This shows which H.264 encoders are compiled into your FFmpeg build. ### Step 2: Interpret Results Common encoder options you may see: | Encoder | Description | Recommendation | |---------|-------------|----------------| | `libx264` | Software H.264 encoder | **Preferred** - widely compatible | | `libopenh264` | OpenH264 software encoder | Use with caution - often has library version mismatches | | `h264_nvenc` | NVIDIA hardware encoder | Good if NVIDIA GPU available | | `h264_videotoolbox` | macOS hardware encoder | Good on macOS | | `h264_vaapi` | Intel VAAPI hardware encoder | Good on Linux with Intel GPU | | `h264_qsv` | Intel QuickSync encoder | Good on Windows/Linux with Intel GPU | ### Step 3: Choose Encoding Strategy **For same-resolution sources (no re-encoding needed):** ```bash # Best option - pass-through without quality loss ffmpeg -i input.mp4 -c:v copy -c:a copy output.mp4 ``` **If libx264 is available:** ```bash # Reliable software encoding ffmpeg -i input.mp4 -c:v libx264 -preset medium -crf 23 -c:a aac output.mp4 ``` **If only libopenh264 is available:** ```bash # Use with caution - may have library issues ffmpeg -i input.mp4 -c:v libopenh264 -c:a aac output.mp4 ``` ### Step 4: Validate Before Batch Processing Always test your encoding command on a small sample file before processing multiple videos or long footage. ## Best Practices 1. **Default to `-c:v copy`** when source and target resolutions match - no quality loss, fastest processing 2. **Prefer libx264** over libopenh264 for software encoding - more stable, better compatibility 3. **Check encoder availability at script startup**, not during execution - fail fast with clear error 4. **Cache encoder check results** if running multiple encoding operations in the same session 5. **Provide fallback options** in automated scripts - try copy first, then libx264, then fail gracefully ## Example Script Template ```bash #!/bin/bash # Check available encoders at startup ENCODERS=$(ffmpeg -encoders 2>/dev/null | grep h264) if echo "$ENCODERS" | grep -q "libx264"; then VIDEO_CODEC="libx264" echo "Using libx264 encoder" elif echo "$ENCODERS" | grep -q "libopenh264"; then VIDEO_CODEC="libopenh264" echo "Warning: Using libopenh264 (may have compatibility issues)" else echo "Error: No H.264 encoder available" echo "Available encoders:" echo "$ENCODERS" exit 1 fi # For same-resolution sources, prefer copy if [ "$SOURCE_RESOLUTION" = "$TARGET_RESOLUTION" ]; then VIDEO_CODEC="copy" echo "Same resolution detected - using stream copy" fi # Encode ffmpeg -i "$INPUT" -c:v "$VIDEO_CODEC" -c:a aac "$OUTPUT" ``` ## Common Errors to Avoid - **Do not assume libx264 is available** - FFmpeg builds vary by system - **Do not use libopenh264 without checking** - frequent library version mismatch errors - **Do not re-encode unnecessarily** - use `-c:v copy` when resolution matches - **Do not skip the encoder check** - always probe before writing encoding logic