FFmpeg视频转换脚本需求：生成MP4/WebM及首帧JPEG（640*360）

Hey there! Let's get this sorted out for you—since you're new to FFmpeg, I'll break this down step by step to meet all your requirements: converting to MP4/WebM, generating a first-frame JPEG, and locking everything to 640×360 resolution. Plus, I'll share easy-to-use drag-and-drop/folder-based tools so you don't have to type commands every time.

First: Fixing Your FFmpeg Command #

Your original command fails because it doesn't specify critical encoding parameters or resolution scaling. FFmpeg needs clear instructions for codecs (especially for WebM/MP4) and resizing. Here's a single command that does everything in one go (saves time by avoiding re-decoding the input):

ffmpeg -i /tmp/video.off \
  -vf scale=640:360 \
  -c:v libx264 -crf 23 -preset medium -c:a aac -b:a 128k /tmp/video.mp4 \
  -c:v libvpx-vp9 -crf 30 -b:v 0 -c:a libopus -b:a 128k /tmp/video.webm \
  -vf "scale=640:360,select=eq(n\,0)" -vframes 1 /tmp/video_thumb.jpg

Let me break down what each part does:

• -vf scale=640:360: Forces the video to resize to your target resolution
• libx264 + crf 23: Standard H.264 codec for MP4 (great compatibility; 18-28 is the recommended quality range—lower = better quality)
• libvpx-vp9 + crf 30: Efficient VP9 codec for WebM (smaller file sizes than H.264; -b:v 0 lets the codec focus entirely on quality)
• select=eq(n\,0) + -vframes 1: Grabs only the first frame of the video to save as a JPEG thumbnail

Easy Drag-and-Drop/Folder Tools #

If you don't want to mess with commands every time, here are ready-to-use scripts for Windows, Linux, and macOS:

Windows Batch Script (Drag-and-Drop)

Save this as convert_videos.bat on your desktop:

@echo off
setlocal enabledelayedexpansion

if "%~1"=="" (
    echo 请把视频文件拖到这个脚本上！
    pause
    exit /b
)

:: Process each dropped file
for %%f in (%*) do (
    set "input=%%f"
    set "output_folder=%%~dpnf"
    mkdir "!output_folder!" 2>nul

    :: Run FFmpeg conversion
    ffmpeg -i "!input!" ^
        -vf scale=640:360 ^
        -c:v libx264 -crf 23 -preset medium -c:a aac -b:a 128k "!output_folder!\%%~nf.mp4" ^
        -c:v libvpx-vp9 -crf 30 -b:v 0 -c:a libopus -b:a 128k "!output_folder!\%%~nf.webm" ^
        -vf "scale=640:360,select=eq(n\,0)" -vframes 1 "!output_folder!\%%~nf_thumb.jpg"

    echo 处理完成: %%~nf
)

echo 所有文件都搞定啦！
pause

How to use: Drag one or more video files onto the batch file. It'll create a folder for each video (in the same directory) with your converted MP4, WebM, and thumbnail.

Linux/macOS Bash Script

Save this as convert_videos.sh, then run chmod +x convert_videos.sh to make it executable:

#!/bin/bash

if [ $# -eq 0 ]; then
    echo "请把视频文件拖到这个脚本上，或者运行 ./convert_videos.sh 视频文件1 视频文件2"
    exit 1
fi

for input in "$@"; do
    output_folder="${input%.*}"
    mkdir -p "$output_folder"

    ffmpeg -i "$input" \
        -vf scale=640:360 \
        -c:v libx264 -crf 23 -preset medium -c:a aac -b:a 128k "$output_folder/$(basename "${input%.*}").mp4" \
        -c:v libvpx-vp9 -crf 30 -b:v 0 -c:a libopus -b:a 128k "$output_folder/$(basename "${input%.*}").webm" \
        -vf "scale=640:360,select=eq(n\,0)" -vframes 1 "$output_folder/$(basename "${input%.*}")_thumb.jpg"

    echo 处理完成: $(basename "$input")
done

echo 所有文件处理完毕！

How to use: Drag video files onto the script, or run it with your video files as arguments.

内容的提问来源于stack exchange，提问作者William Eguienta