pedestrian-traffic-counting-gemini-video-understanding（pedestrian traffic counting Gemini video understanding 控制）

Gemini Video Understanding Skill

Purpose

This skill enables video understanding workflows using the Google Gemini API, including video summarization, question answering, transcription with optional visual descriptions, timestamp-based queries (MM:SS), scene/timeline detection, video clipping, custom FPS sampling, multi-video comparison, and YouTube URL analysis.

When to Use

• Summarizing a video into key points or chapters
• Answering questions about what happens at specific timestamps (MM:SS)
• Producing a transcript (optionally with visual context) and speaker labels
• Detecting scene changes or building a timeline of events
• Analyzing long videos by clipping to relevant segments or reducing FPS
• Comparing multiple videos (up to 10 videos on Gemini 2.5+)
• Analyzing public YouTube videos directly via URL

Required Libraries

The following Python libraries are required:

from google import genai
from google.genai import types
import os
import time

Input Requirements

• File formats: MP4, MPEG, MOV, AVI, FLV, MPG, WebM, WMV, 3GPP
• Size constraints:

- Use inline bytes for small files (rule of thumb: <20MB). - Use the File API upload flow for larger videos (most real videos).

• YouTube:

- Video must be public (not private/unlisted) and not age-restricted. - Provide a valid YouTube URL.

• Duration / context window (model-dependent):

- 2M-token models: ~2 hours (default resolution) or ~6 hours (low-res). - 1M-token models: ~1 hour (default) or ~3 hours (low-res).

• Timestamps: Use MM:SS (e.g., 01:15) when requesting time-based answers.

Output Schema

All extracted/derived content should be returned as valid JSON conforming to this schema:

{
  "success": true,
  "source": {
    "type": "file|youtube",
    "id": "video.mp4|VIDEO_ID_OR_URL",
    "model": "gemini-2.5-flash"
  },
  "summary": "Concise summary of the video...",
  "transcript": {
    "available": true,
    "text": "Full transcript text (may include speaker labels)...",
    "includes_visual_descriptions": true
  },
  "events": [
    {
      "timestamp": "MM:SS",
      "description": "What happens at this time",
      "category": "scene_change|key_point|action|other"
    }
  ],
  "warnings": [
    "Optional warnings about limitations, missing timestamps, or low confidence areas"
  ]
}

Field Descriptions

• success: Whether the analysis completed successfully
• source.type: file for uploaded/local content, youtube for YouTube analysis
• source.id: Filename for local uploads, or URL/ID for YouTube
• source.model: Gemini model used for the request
• summary: High-level video summary
• transcript.*: Transcript payload (may be omitted or available=false if not requested)
• events: Timeline items with MM:SS timestamps (chapters, scene changes, key actions)
• warnings: Any issues that could affect correctness (e.g., “timestamp not found”, “long video clipped”)

Code Examples

Basic Video Analysis (Local Video + File API)

from google import genai
import os
import time

client = genai.Client(api_key=os.getenv("GEMINI_API_KEY"))

# Upload video (File API for >20MB)
myfile = client.files.upload(file="video.mp4")

# Wait for processing
while myfile.state.name == "PROCESSING":
    time.sleep(1)
    myfile = client.files.get(name=myfile.name)

if myfile.state.name == "FAILED":
    raise ValueError("Video processing failed")

response = client.models.generate_content(
    model="gemini-2.5-flash",
    contents=["Summarize this video in 3 key points", myfile],
)

print(response.text)

YouTube Video Analysis (Public Videos Only)

from google import genai
from google.genai import types
import os

client = genai.Client(api_key=os.getenv("GEMINI_API_KEY"))

response = client.models.generate_content(
    model="gemini-2.5-flash",
    contents=[
        "Summarize the main topics discussed",
        types.Part.from_uri(
            uri="https://www.youtube.com/watch?v=VIDEO_ID",
            mime_type="video/mp4",
        ),
    ],
)

print(response.text)

Inline Video (<20MB)

from google import genai
from google.genai import types
import os

client = genai.Client(api_key=os.getenv("GEMINI_API_KEY"))

with open("short-clip.mp4", "rb") as f:
    video_bytes = f.read()

response = client.models.generate_content(
    model="gemini-2.5-flash",
    contents=[
        "What happens in this video?",
        types.Part.from_bytes(data=video_bytes, mime_type="video/mp4"),
    ],
)

print(response.text)

Video Clipping (Analyze a Segment Only)

from google.genai import types

response = client.models.generate_content(
    model="gemini-2.5-flash",
    contents=[
        "Summarize this segment",
        types.Part.from_video_metadata(
            file_uri=myfile.uri,
            start_offset="40s",
            end_offset="80s",
        ),
    ],
)

Custom Frame Rate (Token/Cost Control)

from google.genai import types

# Lower FPS for static content (saves tokens)
response = client.models.generate_content(
    model="gemini-2.5-flash",
    contents=[
        "Analyze this presentation",
        types.Part.from_video_metadata(file_uri=myfile.uri, fps=0.5),
    ],
)

# Higher FPS for fast-moving content
response = client.models.generate_content(
    model="gemini-2.5-flash",
    contents=[
        "Analyze rapid movements in this sports video",
        types.Part.from_video_metadata(file_uri=myfile.uri, fps=5),
    ],
)

Timeline / Scene Detection (MM:SS)

response = client.models.generate_content(
    model="gemini-2.5-flash",
    contents=[
        """Create a timeline with timestamps:
        - Key events
        - Scene changes
        - Important moments
        Format: MM:SS - Description
        """,
        myfile,
    ],
)

Transcription (Optional Visual Descriptions)

response = client.models.generate_content(
    model="gemini-2.5-flash",
    contents=[
        """Transcribe with visual context:
        - Audio transcription
        - Visual descriptions of important moments
        - Timestamps for salient events
        """,
        myfile,
    ],
)

Structured JSON Output (Schema-Guided)

from pydantic import BaseModel
from typing import List
from google.genai import types as genai_types

class VideoEvent(BaseModel):
    timestamp: str  # MM:SS
    description: str
    category: str

class VideoAnalysis(BaseModel):
    summary: str
    events: List[VideoEvent]
    duration: str

response = client.models.generate_content(
    model="gemini-2.5-flash",
    contents=["Analyze this video", myfile],
    config=genai_types.GenerateContentConfig(
        response_mime_type="application/json",
        response_schema=VideoAnalysis,
    ),
)

Best Practices

• Use the File API for most videos (>20MB) and wait for processing to complete before analysis.
• Reduce token usage by clipping to the relevant segment and/or lowering FPS for static content.
• Improve accuracy by being explicit about the desired output (timestamps format, number of events, whether you want scene changes vs actions vs chapters).
• Use gemini-2.5-pro when you need highest-quality reasoning over complex, long, or visually dense videos.

Error Handling

import time

def upload_and_wait(client, file_path: str, max_wait_s: int = 300):
    myfile = client.files.upload(file=file_path)
    waited = 0

    while myfile.state.name == "PROCESSING" and waited < max_wait_s:
        time.sleep(5)
        waited += 5
        myfile = client.files.get(name=myfile.name)

    if myfile.state.name == "FAILED":
        raise ValueError(f"Video processing failed: {myfile.state.name}")
    if myfile.state.name == "PROCESSING":
        raise TimeoutError(f"Processing timeout after {max_wait_s}s")

    return myfile

Common issues:

• Upload processing stuck: wait and poll; fail after a max timeout.
• YouTube errors: verify the video is public and not age-restricted.
• Rate limits: retry with exponential backoff.
• Incorrect timestamps: re-prompt with strict “MM:SS” formatting and request fewer events.

Limitations

• Long-video support is limited by model context and token budget (default vs low-res modes).
• YouTube analysis requires public videos; live streaming analysis is not supported.
• Very long videos may require chunking (clip by time range and process in segments).
• Multi-video comparison is limited (up to 10 videos per request on Gemini 2.5+).

Version History

• 1.0.0 (2026-01-15): Initial release focused on Gemini video understanding (summaries, Q&A, timestamps, clipping, FPS control, YouTube, and structured outputs).

Resources

• Audio API Docs
• Image API Docs
• Video API Docs
• Document API Docs
• Image Gen Docs
• Get API Key
• Pricing