bash - 如何设置 ffmpeg 队列？

Question

我正在尝试在我的服务器上编码许多视频，但 FFMPEG 是资源密集型的，所以我想设置某种形式的队列。我网站的其余部分使用 PHP，但我不知道是否应该使用 PHP、Python、BASH 等。我想我可能需要使用 CRON，但我不确定如何告诉 ffmpeg 启动一个新任务（从列表中）完成之前的任务后。

Answer 1

We will use FIFO (First In First Out) in a bash script. The script needs to run before cron (or any script, any terminal that call the FIFO) to send ffmpeg commands to this script :

#!/bin/bash

pipe=/tmp/ffmpeg

trap "rm -f $pipe" EXIT

# creating the FIFO    
[[ -p $pipe ]] || mkfifo $pipe

while true; do
    # can't just use "while read line" if we 
    # want this script to continue running.
    read line < $pipe

    # now implementing a bit of security,
    # feel free to improve it.
    # we ensure that the command is a ffmpeg one.
    [[ $line =~ ^ffmpeg ]] && bash <<< "$line"
done

Now (when the script is running), we can send any ffmpeg commands to the named pipe by using the syntax :

echo "ffmpeg -version" > /tmp/ffmpeg

And with error checking:

if [[ -p /tmp/ffmpeg ]]; then
    echo "ffmpeg -version" > /tmp/ffmpeg
else
    echo >&2 "ffmpeg FIFO isn't open :/"
fi

They will be queuing automatically.

Answer 2

谢谢你。正是应用这种技术来创建一个 ffmpeg 队列。不过我做了1个小改动。由于某种原因，此队列仅适用于 2 个项目。当第一个项目完成时，我只能发送第三个项目。

我相应地修改了脚本：

while true; do

# added tweak to fix hang
exec 3<> $pipe

# can't just use "while read line" if we 
# want this script to continue running.
read line < $pipe

我基于： https ://stackoverflow.com/questions/15376562/cant-write-to-named-pipe

只是想我应该分享这个以备将来使用。