Develop Reference

MediaPlayer delayed a few seconds before onComplete got called on some devices

I tried to play a local mp4 video file on my TV Box. I found a weird issue with MediaPlayer's playback speed. Here're my logs:
19:30:09.346 E/MediaPlayerManager: currentMediaPlayer's duration = 16021
19:30:09.715 E/MediaPlayerManager: setOnInfoListener - MediaPlayer.MEDIA_INFO_VIDEO_RENDERING_START
19:30:27.982 E/MediaPlayerManager: onComplete
The media duration was 16s, but it took about 18s to complete the video's playback. There's always a 2s delay before the onComplete listener got called. Does anyone have a solution for this?
After some experiments, I found out the issue was the large SurfaceView. If I replaced it with a TextureView or create the SurfaceView with smaller size, there's no extra delays.
P/s: I knew ExoPlayer, but for some specific reason, I could not use it.

The most efficient way to generate mp4 video containing looped boomerang-alike video file?

I've developed an Android app that allows user to create boomerang-alike mp4 video. This video consists of 10 still images being played back and forth quite fast. I know that such video (boomerang effect) can be easily looped from single video file while playing it, but I really need to create a mp4 video that would essentially contain already prepared boomerang video. The output video can be downloaded and played by user on any external player (over which obviously I don't have any control).
For that purpose currently I create a video from images in a loop. The loop starts from 1st picture and goes to 10th picture with 0.25 sec delay between frames, then goes back from 10th to 1st including delay. And there is 5 of those loops, which essentialy means creating a single video from 5 * 10 * 2 = 100 images. I know it's kinda ridiculous, so the time that it takes to prepare this video is riduculous as well (around 1:40 min).
What solution could you recommend assuming that the output video really has to consist of 5 loops back-and-forth? I've thought about creating single loop video (20 pictures) and then create final output video by concatenating it 5 times. But could it be any good? I'm trying to find an efficient yet understandable for a beginner Android programmer way.

You can use FFMPEG to Create boomerang like video below is a simple example code :-
ffmpeg -i input_loop.mp4 -filter_complex "[0]reverse[r];[0][r]concat,loop=5:250,setpts=N/55/TB" output_looped_video.mp4
1.5 seconds of video file as input named input_loop.mp4
n loop=5:250, 5 is number of loops, 250 is frame rate x double length of clip. The setpts is applied to avoid frame drops, and the value 25 should be replaced with the framerate of the clip
setpts=N/<VALUE>/TB" you can alter value according to your need
increase value to speed up boomerang effect
decrease value to slow down boomerang effect

I was looking for a way to create a boomerang video and found a pretty cool example of how to do it on GitHub.
You create the video by using the FFMPEG library org.bytedeco.javacpp-presets to clone the frames.
https://github.com/trantrungduc/boomerang-android
This is the place in code in which you can customize the video loop:
for (int k = 0; k < 3; k++) {
for (Frame frame1 : loop) {
frecorder.record(frame1);
}
for (int i=loop.size()-1;i>=0;i--){
frecorder.record(loop.get(i));
}
}

Exoplayer change current video seamlessly

I want to change current playing video to another seamlessly. But there is a little bit delay before the next video will be playing. I don't know what the next video will be. How I can do this?

You can use playlists with ExoPlayer. This way the playback transitions at the end of item 1 to 2 without buffering.
DynamicConcatenatingMediaSource mainSource = new DynamicConcatenatingMediaSource();
mainSource.addMediaSource(mediaSource1);
player.prepare(mainSource);
// later...
mainSource.addMediaSource(mediaSource2);
As soon as you know the second media you can add it while the player is playing.
https://medium.com/google-exoplayer/dynamic-playlists-with-exoplayer-6f53e54a56c0

precision of Android MediaPlayer seekTo

I have a number of mp3 files that I use with Android MediaPlayer to play from certain offsets.
Using seekTo() seems to stop at correct location. player.getCurrrentPosition() returns the correct offset, but in some cases the real position is off for as much as 200 ms. The files are about 3 minutes worth of recording and the incorrect offsets seem to appear at the end. Of some of the files.
I have the same effect either trying with Android 4.0.3 device or 4.3 emulator.
Anybody has experience with "finetuning" MediaPlayer offsets? Any experience why MediaPlayer might not be working correctly with some files? They are all CBR, stereo, some have sampling frequency 22050, some 44100, different bitrates.
I'm setting the offsets from another program and saving to mp3 tags, then in case of doubt verifying manually using Audacity. Audacity agrees with my estimate of what the correct offset is, MediaPlayer seems to disagree.
I'm aware that I could use AudioTrack with raw sound files and have a better control, however it might be impractical as there are many mp3 files, so using raw sound data will make pretty large application or many large data files.
The code is nothing fancy:
player.seekTo(start);
player.start();
CountDownTimer timer = new CountDownTimer(length, 100) {
#Override
public void onTick(long millisUntilFinished) {
if (player!=null) setInt(R.id.nLocation, player.getCurrentPosition());
}
#Override
public void onFinish() {
if (player!=null) {
if (player.isPlaying()) {
player.pause();
}
setInt(R.id.nLocation, player.getCurrentPosition());
player.stop();
player.release();
player = null;
}
}
};
timer.start();

I did not manage to find the rule why the MediaPlayer interprets offset (seekTo) differently for a group of MP3 files. For example when creating a new MP3 file with the same parameters from Audacity+Lame (MPEG1, Layer III, 44100 Hz, 192 Kb/s) it worked perfectly.
However:
this can be reproduced - rip MP3 file using Windows Media Player, settings: MP3, 192 kb/s [added when edited]
I found the workaround that seems to work for any recording.
The background - in order to tell MediaPlayer to play from certain offset, I store certain data in MP3 tags. I use a separate program to set up the playback (in frames): Label A, start frame=1000, length=100 frames, Label B, start #1500 etc. Now when I need to play it back, I read the MP3 headers, determine the frame length, for example 26.12245 ms/frame and calculate the offset (1000 frames will be 26122 ms).
The workaround is to store in MP3 tag also the frame count and length in ms (or pass through again and count the frames). Then when start MediaPlayer, compare MediaPlayer.getDuration() (MediaPlayer estimate) with the duration stored in MP3 tag. Then adjust the frame size:
adjustedFrameSizeMs = realFrameSizeMs + (player.getDuration()-storedDurationMs)/storedframeCount;
In my case (for the files with incorrect offset) the adjusted frame length always was between 26.08 and 26.09 ms (instead of 26.12245).
I attempted to try see if this is because Android plays the recording quicker (so it estimates the "real time", not the time according to frame size and frame count). It seems that it really does plays quicker. But even quicker than its own estimate. For example a recording of about 1 hour:
my estimate: 2448 s
MediaPlayer: 2444 s (4 sec difference)
Audacity: 2442 s (here we are in disagreement)
Foobar: 2448 s (another witness that agrees with my estimate :-)
MediaPlayer, real play time: 2438 s
The real playtime was 6 s (0.25%) less than MediaPlayer own estimate. Another attempt on a different sample gave the same percentage difference. However the fact that Audacity and Foobar did not always agree with my estimates, does not let me put all the blame on MediaPlayer.

Android Vitamio weired buffering on progressive download stream

I try to stream (progressive e.g: http://server.com/video.mp4)
when i use the standard google mediaplayer (VideoView from android package) and register an onBufferingUpdateListener then i get the bufferpercentage that refers to the download state of the hole video. This player has also a loading view where i can see the buffer state.
This bufferpercentage and view shows me how much of the video has been downloaded.
Now when i use the Vitamio player, the onBufferingUpdateListener shows me after a few seconds 99 percent of buffering and there is no loading view too. And when i pause the playback it stops buffering immediately instead of continue buffering like the google videoview does. This is very usefull if you have a slow http stream.
Is there a way to make the vitamio-videoplayer buffer the videofiles in the same way as the google videoplayer does?
thank you
daniel

Sorry i posted that question as wrong user. Here the Answer of what i tried:
VideoView (android default - just plays few video formats) from inside the android.widget and from io.vov.vitamio.widget (vitamio - plays most video formats) package has the same structure. In both you can register an OnBufferingUdateListener that returns the bufferstate in percent:
videoview.setOnBufferingUpdateListener(new io.vov.vitamio.MediaPlayer.OnBufferingUpdateListener() {
public void onBufferingUpdate(io.vov.vitamio.MediaPlayer mp, int i) {
Log.v(TAG, "Buffer percentage done: "+i);
}
});
or with the android default VideoView:
videoview.setOnBufferingUpdateListener(new android.media.MediaPlayer.OnBufferingUpdateListener() {
public void onBufferingUpdate(android.media.MediaPlayer mp, int i) {
Log.v(TAG, "Buffer percentage done: "+i);
}
});
If i use android.widget.VideoView the buffer percentage slowly increases until it reaches 100% - The video file has been downloaded completely. And it continues updating BufferingUpdate when i press the pause button.
When i use io.vov.vitamio.widget.VideoView the percentage reaches 100% within seconds. Then the video starts and the OnBufferingUpdateListener never gets called again (when i call getBufferPercentage it is always at 99 percent. That seems to be the reason). And as i sayed: It seems to stop buffering when i press the pause button.
I think the buffering works different in vitamio. But that's crap. Especially when i stream videos from the web and the video datarate is higher than the download speed i need to prebuffer the video by pressing pause and wait until it has downloaded enough data to watch it smoothly. Hope you got what i mean. thank you