The development summary of the function of fast playback of audio and video in any format on the web page.

The development focus is pc End , Mobile terminal does not consider .

To realize the transmission of audio and video from the user to the server , After uploading, you can drag the progress bar to watch .

h5 Self contained video Tags do not support most audio and video formats , Don't consider .

Consider using streaming media , Turn the source video into a video stream and push it to the web player .

Use nginx+nginx-rtmp-module+ffmpeg Set up a streaming media server , Use rtmp and hls Experiment with two ways of streaming , use vlc Play successfully , But I found it was live , No progress , I'll have a good time , But I also learned about the realization of live broadcast function . This plan doesn't work , Abandon .

hls Streaming media , It's a m3u8 file , Inside is a list of video clip files , a pile ts Small file in format , So I want to use this way to realize .

use ffmpeg For video m3u8 Automatic segmentation , Will generate a m3u8 Files and a bunch of ts file .

command ： ffmpeg -i file name  -c:v libx264 -c:a aac -hls_time 10 -hls_list_size 0  -strict -2 -f hls output.m3u8

-c:v -c:a： They are the encoding types of video and audio

-hls_time n: Set the length of each piece , The default value is 2. The unit is in seconds

-hls_list_size n: Set the maximum number of entries saved in the playlist , Set to 0 There will be pieces of information saved , The default value is 5

-hls_wrap n: Set how many pieces to start covering , If set to 0 Will not cover , The default value is 0. This option avoids storing too much on disk
slice , And it can limit the number of pieces written to the disk
-hls_start_number n: Set the in the playlist sequence number The value of is number, The default value is 0

First , Generated file , To find a way to play on the web , Tried several players , In the end ckplayer, The official help document contains how to play m3u8 The method of streaming media , The principle is to use flash Play it , One swf player . The player first requests m3u8 file , Calculate the total progress of the video according to the duration in the file list . Request corresponding when dragging progress ts file . A series of requests are sent by the player .

Try to get the request of the player , Use django Create a project , Set up a static folder , Put the generated video file in , Write it on the webpage m3u8 File path , It will play normally , But cannot listen for player requests . So put the video file in the normal folder , Link according to the player's request , Set up a url Corresponding to a method in the background , This method will be used for every request , You can get which file is requested , Which file is requested , I found this file , Open in stream （open(tsfilepath, 'rb')） And back to , Played successfully .

Realize any progress playback , According to the requested document , It is calculated that the file starts from the second of the source file , From here, you can intercept the video clip and return .

The key codes are as follows ：

Sir, it becomes a temporary document

os.system("ffmpeg -i %s -ss %d -t %d  -c:v libx264 -c:a aac -g 5 -sc_threshold 0 %s" % ( Source file path ,  Number one ts file *  How long is each segment ,  How long is each segment ,  Generate ts route ))

 Set the start_time To play normally , The specific principle is not very clear .
os.system("ffmpeg -i %s/%s -ss %d -t %d  -c:v copy -c:a copy -g 5 -sc_threshold 0 %s/%s" % (tsdirpath, tsname, -tsnum * cuttime, cuttime * (tsnum + 1), tsdirpath,  tsfile))
os.system("rm -f %s/%s" % (tsdirpath, tsname))

-ss Starting time

-t A few seconds after the start time , That is, the length of this segment

When capturing video -i and -ss The front and back position of the has a great influence .

-i In the first place, search according to the key frame , Fast .

-i After that, search frame by frame , Very slow , High precision , Suitable for small files .

For details, see ：http://trac.ffmpeg.org/wiki/Seeking Click to open the link

summary ：

1、 Generate... Manually m3u8 file , Need to get the total length of the file , Set the length of each clip .
 filemsg = os.popen("ffprobe -v error -show_entries format=duration -print_format json %s" % srcvideopath).read()
print(filemsg)
length = float(json.loads(filemsg)['format']['duration'])

2、 Generate corresponding according to the request ts File and return .