FFmpeg输出寻求结果到Android LruCache [英] FFmpeg output seeking result to Android LruCache

问题描述

亲爱的StackOverflower，

Dear fellow StackOverflower,

在我的Android应用程序中，我正在尝试使用 ffmpeg-android-java 显示在 ImageView 中。问题是使用典型的 ffmpeg 的 -ss 寻找命令将需要将输出写入内存中假设是对表演的重大影响：

In my Android application, I'm trying to quickly retrieve a frame from a video using ffmpeg-android-java to display in an ImageView. The problem is using a typical ffmpeg's -ss seeking command will require to write the output into the memory which I suppose is the big hit on performance:

ffmpeg -ss 00:23:00 -i Mononoke.Hime.mkv -frames：v 1 out1 .jpg

上面的典型命令执行大概需要700到1200毫秒。因此，我不想写入内存，而是将其写入 LruCache 希望实现更好的性能。

A typical command execution like above takes around 700 - 1200 milliseconds. So instead of writing into the memory, I would like to write it into LruCache hoping to achieve a better performance.

问题是 ffmpeg-android-java 是执行 ffmpeg 命令的包装器，所以我不知道如何正确提供 LruCache 的命令地址。

The problem is ffmpeg-android-java is a wrapper to execute ffmpeg command and as such I don't know how to correctly supply the LruCache's address for the command.

以下是我的代码片段：

private void seekToPosition(long currentVideoPosition){

    String position = DiskUtils.formatMillisForFFmpeg(currentVideoPosition);

    String[] cmd = {"-ss", String.valueOf(position), "-i", mVideoPath,
                    "-y", "-an", "-frames:v", "1",
                    "/storage/emulated/0/Videos/out.jpg"}; //this the problem, I would like to change this to the address of LruCache

    try {
        // to execute "ffmpeg -version" command you just need to pass "-version"
        mFFmpeg.execute(cmd, new ExecuteBinaryResponseHandler() {

            long start;
            long end;

            @Override
            public void onStart() {
                canSeek = false;
                start = System.currentTimeMillis();
            }

            @Override
            public void onProgress(String message) {}

            @Override
            public void onFailure(String message) {
                Log.d(TAG, "FFmpeg cmd failure");
            }

            @Override
            public void onSuccess(String message) {
                Log.d(TAG, "FFmpeg cmd success");

                /*mFFmpeg.killRunningProcesses();
                Log.d(TAG, "FFmpeg kill running process: " + mFFmpeg.killRunningProcesses());*/
            }

            @Override
            public void onFinish() {
                canSeek = true;
                Log.d(TAG, "FFmpeg cmd finished: is FFmpeg process running: " + mFFmpeg.isFFmpegCommandRunning());
                end = System.currentTimeMillis();
                Log.d(TAG, "FFmpeg excuted in: " + (end - start) + " milliseconds");
            }
        });
    } catch (FFmpegCommandAlreadyRunningException e) {
        // Handle if FFmpeg is already running
        Log.d(TAG, "FFmpeg exception: " + e);
    }
} 

推荐答案

回答我自己的问题，我还没有找到解决方案，因为它本质上是不可能的。所以，我采取了艰难的方式编译FFmpeg，并使用JNI将其用作一个库。

To answer my own question, I haven't found the solution for this yet as it's kind of impossible in nature. So instead, I take the hard way of compiling the FFmpeg and using the JNI to use it as a library.

你可以看看我的一步一步说明，如果您需要一些关于使用Android Studio构建和使用FFmpeg的指导，因为我知道试图找出这个出来是一场真正的噩梦。

You can take a look at my step-by-step instructions if you need some guidance on building and using FFmpeg with Android Studio because I know trying to figure this out is a real nightmare.

对不起，我无法发布所有的说明，因为它太久了，加上我更容易保存1个信息来源的最新信息。

Sorry I can't post all the instructions here as it is way too long, plus it is easier for me to keep 1 source of information up-to-date.

这篇关于FFmpeg输出寻求结果到Android LruCache的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！