Zhipu AI Automatic Speech Recognition (ASR)

Transcribe Chinese audio files to text using Zhipu AI's GLM-ASR model.

Setup

1. Get your API Key: Get a key from Zhipu AI Console

2. Set it in your environment:

export ZHIPU_API_KEY="your-key-here"

Supported Audio Formats

• WAV - Recommended, best quality
• MP3 - Widely supported
• OGG - Auto-converted to MP3
• M4A - Auto-converted to MP3
• AAC - Auto-converted to MP3
• FLAC - Auto-converted to MP3
• WMA - Auto-converted to MP3

Note: The script automatically converts unsupported formats to MP3 using ffmpeg. Only WAV and MP3 are accepted by the API, but you can use any format that ffmpeg supports.

File Constraints

• Maximum file size: 25 MB
• Maximum duration: 30 seconds
• Recommended sample rate: 16000 Hz or higher
• Audio channels: Mono or stereo

Usage

Basic Transcription

Transcribe an audio file with default settings:

bash scripts/speech_to_text.sh recording.wav

Transcription with Context

Provide previous transcription or context for better accuracy:

bash scripts/speech_to_text.sh recording.wav "这是之前的转录内容，有助于提高准确性"

Transcription with Hotwords

Use custom vocabulary to improve recognition of specific terms:

bash scripts/speech_to_text.sh recording.mp3 "" "人名,地名,专业术语,公司名称"

Full Options

Combine context and hotwords:

bash scripts/speech_to_text.sh recording.wav "会议记录片段" "张三,李四,项目名称"

Parameters:

• audio_file (required): Path to audio file (.wav or .mp3)
• prompt (optional): Previous transcription or context text (max 8000 chars)
• hotwords (optional): Comma-separated list of specific terms (max 100 words)

Features

Context Prompts

Why use context prompts:

• Improves accuracy in long conversations
• Helps with domain-specific terminology
• Maintains consistency across multiple segments

When to use:

• Multi-part conversations or meetings
• Technical or specialized content
• Continuing from previous transcriptions

Example:

bash scripts/speech_to_text.sh part2.wav "第一部分的转录内容：讨论了项目进展和下一步计划"

Hotwords

What are hotwords: Custom vocabulary list that boosts recognition accuracy for specific terms.

Best use cases:

• Proper names (people, places)
• Domain-specific terminology
• Company names and products
• Technical jargon
• Industry-specific terms

Examples:

# Medical transcription
bash scripts/speech_to_text.sh medical.wav "" "患者,症状,诊断,治疗方案"

# Business meeting
bash scripts/speech_to_text.sh meeting.wav "" "张经理,李总,项目代号,预算"

# Tech discussion
bash scripts/speech_to_text.sh tech.wav "" "API,数据库,算法,框架"

Workflow Examples

Transcribe a Meeting

# Part 1
bash scripts/speech_to_text.sh meeting_part1.wav

# Part 2 with context
bash scripts/speech_to_text.sh meeting_part2.wav "第一部分讨论了项目进度" "张总,李经理,项目名称"

# Part 3 with context
bash scripts/speech_to_text.sh meeting_part3.wav "前两部分讨论了项目进度和预算" "张总,李经理,项目名称"

Transcribe a Lecture

bash scripts/speech_to_text.sh lecture.wav "" "教授,课程名称,专业术语1,专业术语2"

Process Multiple Files

for file in recording_*.wav; do
    bash scripts/speech_to_text.sh "$file"
done

Audio Quality Tips

Best practices for accurate transcription:

1. Clear audio source

   • Minimize background noise
   • Use good quality microphone
   • Speak clearly and at moderate pace

2. Optimal audio settings

   • Sample rate: 16000 Hz or higher
   • Bit depth: 16-bit or higher
   • Single channel (mono) is sufficient

3. File preparation

   • Remove silence from beginning/end
   • Normalize audio levels
   • Ensure consistent volume

Output Format

The script outputs JSON with:

• id: Task ID
• created: Request timestamp (Unix timestamp)
• request_id: Unique request identifier
• model: Model name used
• text: Transcribed text

Example output:

{
  "id": "task-12345",
  "created": 1234567890,
  "request_id": "req-abc123",
  "model": "glm-asr-2512",
  "text": "你好，这是转录的文本内容"
}

Troubleshooting

File Size Issues:

• Split audio files larger than 25 MB
• Reduce sample rate or bit depth
• Use compression (MP3) for smaller files

Duration Issues:

• Split recordings longer than 30 seconds
• Process segments separately
• Use context prompts to maintain continuity

Poor Accuracy:

• Improve audio quality
• Use hotwords for specific terms
• Provide context prompts
• Ensure clear speech and minimal noise

Format Issues:

• Ensure file is .wav or .mp3
• Check file is not corrupted
• Verify audio can be played by standard players

Limitations

• Maximum audio duration: 30 seconds per request
• File size limit: 25 MB
• Maximum hotwords: 100 terms
• Context prompt limit: 8000 characters
• Best performance with Chinese language audio

Performance Notes

• Typical transcription time: 1-3 seconds
• Real-time or faster for most audio
• Processing time scales with audio quality and length