This blog is only for my spare time to record articles , Publish to , Only for users to read , If there is any infringement , Please let me know , I'll delete it .

Preface

In recent days, , A little friend said he wanted to read an article about video download , see , take bilibili Here we go .
Because there is no deep right bilibili Conduct research , Lead to poor readability of the article , No joy, no spray. .
Although it's just a taste . But the goal of downloading video can be achieved .

About video clarity ：

If it's not logged in , There's no clarity .
If you open a video when you're logged in , Choose HD , that ！！ Use your string mid The requested videos are all HD （ The video itself has no HD except ）.

1. Ideas

Let's talk about the whole idea here ！

1. Find the audio and video url Is the key
2. After downloading video and audio respectively , Then mix video and audio （ That is to say, the picture and sound are combined into one file ）.

Don't talk much , Let's start with ！！！

2. analysis

The video in the picture below is an example . In this paper, for Firefox browser , Convenient to show the effect of bag grabbing .
The first is to open the developer tool to grab the package . Here's the picture ：

See the grab page The media classification , All are mp4 Data packets in format , The packet size is from 107 Bytes to 2.30MB Unequal . There is an interesting rule as follows ：

1. 107 Bytes of packets are passed through OPTIONS Method request for .
2. The bigger packets go through GET Mode request .
3. There are two repeated URL( Guess it's video and audio )
4. The request header Range Field , The next file will be followed by the last file's byte mantissa ,1 File is 0-973,2 File is 974-1653...

In that case , Let's use the code to request a look .

After code execution , It generates a 1kb Of test.mp4 file , Obviously , Wrong opening

Why is it wrong ？？ I think the file is too small , Modify the request header Range The value is 0-1024000, Run the code again .
This time a 1001kb Of mp4 file , And it can play ！！ But there's no sound in the video , confirmed 了 bilibili Video files are separated from audio and video .

It says , Most of the packets caught are two duplicates URL, Now ask for another URL have a look .

The code just will URL Made modifications , The request header has not changed .

（ No audio in the picture , But there are voices ）, such , So I finished this job .

Here we are. , The job of grabbing the bag has been finished , The origin of video and audio is also clear , That's the question , Such a long string URL Where did it come from ？
！！！ Look at the source code .
puzzled , But forget the simplest way , View source code of webpage （ It took a long time to discover , The original source code contains ！！！）

video Of URL：

audio Of URL：

Here we are. , The rest use regular matching source code inside video and audio Of URL It's not a problem ！！！

The remaining questions ：

• You also need to mix video and audio , This can be used ffmpeg Complete or use format factory .

2.1 ffmpeg Composite audio and video

2.1.1 install ffmpeg

ffmpeg Official website ：https://ffmpeg.zeranoe.com/builds/

Click in to download the corresponding computer version .

Download the file and unzip it into the following figure ：

And then bin The directory of this file is added to System environment variable that will do . Here's the picture ：

Explain a little bit about what's used here ffmpeg The meaning of the command is ：

Interested partners can click ffmepeg Chinese document , Deepen understanding .

I also use subprocess modular , Use to generate subprocesses , And they can be piped into their input / Output / error , And get their return values .

import subprocess
def merge_video_and_audio(video_name):
"""
Audio and video merging function , utilize ffmpeg Merge audio and video
:param video_name: Pass in the title
:return:
"""
cmd = f'ffmpeg -i "{video_name}.m4s" -i "{video_name}.mp3" -c copy "{video_name}.mp4" -loglevel quiet'
subprocess.Popen(command, shell=True)
print(f'{video_name}.mp4 merger ！！！')

What it looks like after executing the code ：

• You can see that it has been successfully synthesized mp4 Format video .

2.2 Format factory synthesis audio and video

ps： Other videos are used here as examples .
1. Download good audio and video ：

2. Open the format factory ：

3. Audio and video streaming ：

Last , Wait for the mixed model to finish .
Above code , Download... Here .
Code self access ： https://github.com/SunriseCai/spiderCode

3. Words behind

If you guys are interested , Can improve the code . Some suggestions are as follows ：

1. Add the function of manually inputting search video
2. utilize Pyqt5 Make it visual bilibili Video download widget

Friends, if you improve the code, remember to send me a copy ！！！