Feedback: guides-downsampling

Documentation Feedback

Original URL: https://www.assemblyai.com/docs/guides/downsampling
Category: guides
Generated: 05/08/2025, 4:41:20 pm

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Claude Sonnet 4 Feedback

Generated: 05/08/2025, 4:41:19 pm

Technical Documentation Analysis: Audio File Downsampling Guide

Overall Assessment

This documentation provides solid foundational information but has several gaps that could frustrate users. The technical content is generally accurate, but the structure and user guidance need improvement.

Critical Issues to Address

1. Missing Information

Quantified Quality Trade-offs

• Add a comparison table showing transcription accuracy at different sample rates/bitrates
• Include recommended minimum thresholds for different use cases (podcasts, meetings, phone calls)

Error Handling

• No guidance on what happens when FFmpeg fails
• Missing information about file size limits for AssemblyAI API
• No troubleshooting section for common conversion errors

Cost/Performance Metrics

• Include actual file size comparisons (e.g., “Converting from 44.1kHz WAV to 16kHz MP3 typically reduces file size by 80%”)
• Processing time implications are mentioned but not quantified

2. Structural Improvements

Reorganize for User Journey

Suggested new structure:
1. Quick Start (common scenarios)
2. Understanding Audio Basics
3. Analysis & Decision Making
4. Conversion Examples
5. Integration & Automation
6. Troubleshooting

Add Decision Framework Create a flowchart or decision tree helping users choose appropriate settings based on:

• Source audio quality
• Use case requirements
• Storage/bandwidth constraints

3. Enhanced Examples

Current Issue: Examples are generic and don’t show real-world scenarios.

Improved Examples Needed:

# Podcast optimization (speech-focused)
ffmpeg -i podcast.wav -ar 22050 -ac 1 -ab 96k -q:a 4 podcast_optimized.mp3

# Meeting recording (multiple speakers)
ffmpeg -i meeting.wav -ar 16000 -ac 2 -ab 128k meeting_optimized.mp3

# Phone call quality (minimal bandwidth)
ffmpeg -i call.wav -ar 8000 -ac 1 -ab 64k call_optimized.mp3

4. User Pain Points & Solutions

Pain Point: Users don’t know if their conversion was successful Solution: Add verification steps

# Verify conversion quality
ffprobe -v quiet -show_entries format=duration,size,bit_rate -of csv=p=0 output.mp3

Pain Point: No guidance on batch processing Solution: Add batch conversion examples

Pain Point: Integration complexity unclear Solution: Add complete workflow example with error handling

5. Code Examples Enhancement

Current Python example lacks error handling and real-world features:

import subprocess
import os
from pathlib import Path

class AudioConverter:
    def __init__(self):
        self.verify_ffmpeg()

    def verify_ffmpeg(self):
        """Verify FFmpeg is installed and accessible"""
        try:
            subprocess.run(['ffmpeg', '-version'],
                         capture_output=True, check=True)
        except (subprocess.CalledProcessError, FileNotFoundError):
            raise RuntimeError("FFmpeg not found. Please install FFmpeg.")

    def convert_for_transcription(self, input_file, output_file=None,
                                preset='standard'):
        """Convert audio with presets for different use cases"""
        presets = {
            'standard': ['-ar', '16000', '-ac', '1', '-ab', '128k'],
            'high_quality': ['-ar', '22050', '-ac', '1', '-ab', '192k'],
            'minimal': ['-ar', '8000', '-ac', '1', '-ab', '64k']
        }

        if not os.path.exists(input_file):
            raise FileNotFoundError(f"Input file not found: {input_file}")

        if output_file is None:
            path = Path(input_file)
            output_file = f"{path.stem}_converted.mp3"

        command = ['ffmpeg', '-i', input_file] + presets[preset] + [output_file]

        # Show progress and capture errors
        process = subprocess.run(command, capture_output=True, text=True)

        if process.returncode != 0:
            raise RuntimeError(f"Conversion failed: {process.stderr}")

        # Verify output file was created
        if not os.path.exists(output_file):
            raise RuntimeError("Output file was not created")

        return {
            'output_file': output_file,
            'original_size': os.path.getsize(input_file),
            'converted_size': os.path.getsize(output_file),
            'compression_ratio': os.path.getsize(input_file) / os.path.getsize(output_file)
        }

6. Additional Sections Needed

Troubleshooting Section

## Common Issues

### "Permission denied" errors
- Ensure FFmpeg has write permissions to output directory
- Check if output file is already open in another application

### "Invalid codec" errors
- Verify input file isn't corrupted: `ffmpeg -v error -i input.wav -f null -`
- Try different codec: add `-c:a libmp3lame` for MP3 output

### Very large output files
- Input may already be compressed - check with ffprobe first
- Consider using variable bitrate: `-q:a 4` instead of `-ab 128k`

Performance Optimization Section

## Batch Processing & Performance

### Process multiple files efficiently
```bash
# Batch convert all WAV files in directory
for file in *.wav; do
    ffmpeg -i "$file" -ar 16000 -ac 1 -ab 128k "${file%.wav}.mp3"
done

7. Specific Actionable Changes

1. Add upfront summary: Create a “Quick Reference” table showing recommended settings for common scenarios
2. Improve prerequisites: Add installation verification steps
3. Add validation examples: Show how to verify conversion success
4. Include complete workflow: From upload through transcription with converted audio
5. Add performance benchmarks: Include typical conversion times and file size reductions
6. Create troubleshooting guide: Address common FFmpeg errors
7. Add mobile/web considerations: Guidance for client-side conversion limitations

8. Missing Technical Details

• Supported input formats comprehensive list
• Maximum file size limits
• Rate limiting considerations for API usage
• Bandwidth optimization strategies
• Quality assessment methods post-conversion

This documentation would benefit from a more user-centric approach with practical examples, better error handling, and clearer guidance on making quality vs. size trade-offs.

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