Issue in recording video
I am trying to record video in 480*480 resolution like in vine using javacv. As a starting point I used the sample provided in https://github.com/bytedeco/javacv/blob/master/samples/RecordActivity.java Video is getting recorded (but not in the desired resolution) and saved.
But the issue is that 480*480 resolution is not supported natively in android. So some pre processing needs to be done to get the video in desired resolution.
So once I was able to record video using code sample provided by javacv, next challenge was on how to pre process the video. On research it was found that efficient cropping is possible when final image width required is same as recorded image width. Such a solution was provided in the SO question,Recording video on Android using JavaCV (Updated 2014 02 17). I changed onPreviewFrame method as suggested in that answer.
@Override
public void onPreviewFrame(byte[] data, Camera camera) {
if (audioRecord == null || audioRecord.getRecordingState() != AudioRecord.RECORDSTATE_RECORDING) {
startTime = System.currentTimeMillis();
return;
}
if (RECORD_LENGTH > 0) {
int i = imagesIndex++ % images.length;
yuvImage = images[i];
timestamps[i] = 1000 * (System.currentTimeMillis() - startTime);
}
/* get video data */
imageWidth = 640;
imageHeight = 480
int finalImageHeight = 360;
if (yuvImage != null && recording) {
ByteBuffer bb = (ByteBuffer)yuvImage.image[0].position(0); // resets the buffer
final int startY = imageWidth*(imageHeight-finalImageHeight)/2;
final int lenY = imageWidth*finalImageHeight;
bb.put(data, startY, lenY);
final int startVU = imageWidth*imageHeight + imageWidth*(imageHeight-finalImageHeight)/4;
final int lenVU = imageWidth* finalImageHeight/2;
bb.put(data, startVU, lenVU);
try {
long t = 1000 * (System.currentTimeMillis() - startTime);
if (t > recorder.getTimestamp()) {
recorder.setTimestamp(t);
}
recorder.record(yuvImage);
} catch (FFmpegFrameRecorder.Exception e) {
Log.e(LOG_TAG, "problem with recorder():", e);
}
}
}
}
Please also note that this solution was provided for an older version of javacv. The resulting video had a yellowish overlay covering 2/3rd part. Also there was empty section on left side as the video was not cropped correctly.
So my question is what is the most appropriate solution for cropping videos using latest version of javacv?
Code after making change as suggested by Alex Cohn
@Override
public void onPreviewFrame(byte[] data, Camera camera) {
if (audioRecord == null || audioRecord.getRecordingState() != AudioRecord.RECORDSTATE_RECORDING) {
startTime = System.currentTimeMillis();
return;
}
if (RECORD_LENGTH > 0) {
int i = imagesIndex++ % images.length;
yuvImage = images[i];
timestamps[i] = 1000 * (System.currentTimeMillis() - startTime);
}
/* get video data */
imageWidth = 640;
imageHeight = 480;
destWidth = 480;
if (yuvImage != null && recording) {
ByteBuffer bb = (ByteBuffer)yuvImage.image[0].position(0); // resets the buffer
int start = 2*((imageWidth-destWidth)/4); // this must be even
for (int row=0; row<imageHeight*3/2; row++) {
bb.put(data, start, destWidth);
start += imageWidth;
}
try {
long t = 1000 * (System.currentTimeMillis() - startTime);
if (t > recorder.getTimestamp()) {
recorder.setTimestamp(t);
}
recorder.record(yuvImage);
} catch (FFmpegFrameRecorder.Exception e) {
Log.e(LOG_TAG, "problem with recorder():", e);
}
}
}
Screen shot from video generated with this code (destWidth 480) is
Next I tried capturing a video with destWidth speciified as 639. The result is
When destWidth is 639 video is repeating contents twice. When it is 480, contents are repeated 5 times and the green overlay and distortion is more.
Also When the destWidth = imageWidth, video is captured properly. ie, for 640*480 there is no repetition of video contents and no green overlay.
Converting frame to IplImage
When this question was asked first, I missed to mention that the record method in FFmpegFrameRecorder is now accepting object of type Frame whereas earlier it was IplImage object. So I tried to apply Alex Cohn's solution by converting Frame to IplImage.
//---------------------------------------
// initialize ffmpeg_recorder
//---------------------------------------
private void initRecorder() {
Log.w(LOG_TAG,"init recorder");
imageWidth = 640;
imageHeight = 480;
if (RECORD_LENGTH > 0) {
imagesIndex = 0;
images = new Frame[RECORD_LENGTH * frameRate];
timestamps = new long[images.length];
for (int i = 0; i < images.length; i++) {
images[i] = new Frame(imageWidth, imageHeight, Frame.DEPTH_UBYTE, 2);
timestamps[i] = -1;
}
} else if (yuvImage == null) {
yuvImage = new Frame(imageWidth, imageHeight, Frame.DEPTH_UBYTE, 2);
Log.i(LOG_TAG, "create yuvImage");
OpenCVFrameConverter.ToIplImage converter = new OpenCVFrameConverter.ToIplImage();
yuvIplimage = converter.convert(yuvImage);
}
Log.i(LOG_TAG, "ffmpeg_url: " + ffmpeg_link);
recorder = new FFmpegFrameRecorder(ffmpeg_link, imageWidth, imageHeight, 1);
recorder.setFormat("flv");
recorder.setSampleRate(sampleAudioRateInHz);
// Set in the surface changed method
recorder.setFrameRate(frameRate);
Log.i(LOG_TAG, "recorder initialize success");
audioRecordRunnable = new AudioRecordRunnable();
audioThread = new Thread(audioRecordRunnable);
runAudioThread = true;
}
@Override
public void onPreviewFrame(byte[] data, Camera camera) {
if (audioRecord == null || audioRecord.getRecordingState() != AudioRecord.RECORDSTATE_RECORDING) {
startTime = System.currentTimeMillis();
return;
}
if (RECORD_LENGTH > 0) {
int i = imagesIndex++ % images.length;
yuvImage = images[i];
timestamps[i] = 1000 * (System.currentTimeMillis() - startTime);
}
/* get video data */
int destWidth = 640;
if (yuvIplimage != null && recording) {
ByteBuffer bb = yuvIplimage.getByteBuffer(); // resets the buffer
int start = 2*((imageWidth-destWidth)/4); // this must be even
for (int row=0; row<imageHeight*3/2; row++) {
bb.put(data, start, destWidth);
start += imageWidth;
}
try {
long t = 1000 * (System.currentTimeMillis() - startTime);
if (t > recorder.getTimestamp()) {
recorder.setTimestamp(t);
}
recorder.record(yuvImage);
} catch (FFmpegFrameRecorder.Exception e) {
Log.e(LOG_TAG, "problem with recorder():", e);
}
}
}
But the videos generated with this method contained only green frames.
To begin with, it's pre-processing, not post-processing the video.
I don't know what changes you need to tune the solution for new version of javacv, I hope they keep the library backwards compatible.
Your buffer is 640 pixels wide, and 480 pixels high. You want to crop out 480x480.
This means that you need a loop that will copy every line to the IplImage, something like this:
private int imageWidth = 640;
private int imageHeight = 480;
private int destWidth = 480;
@Override
public void onPreviewFrame(byte[] data, Camera camera) {
if (data.length != imageWidth*imageHeight) {
Camera.Size sz = camera.getPreviewSize();
imageWidth = sz.width;
imageHeight = sz.height;
destWidth = imageHeight;
}
ByteBuffer bb = (ByteBuffer)yuvImage.image[0].position(0); // resets the buffer
int start = 2*((imageWidth-destWidth)/4); // this must be even
for (int row=0; row<imageHeight*3/2; row++) {
bb.put(data, start, destWidth);
start += imageWidth;
}
recorder.record(yuvImage);