问题
NOTE: I have updated this since originally asking the question to reflect some of what I have learned about loading live camera images into the ffmpeg libraries.
I am using ffmpeg from javacv compiled for Android to encode/decode video for my application. (Note that originally, I was trying to use ffmpeg-java, but it has some incompatible libraries)
Original problem: The problem that I've run into is that I am currently getting each frame as a Bitmap (just a plain android.graphics.Bitmap) and I can't figure out how to stuff that into the encoder.
Solution in javacv's ffmpeg: Use avpicture_fill(), the format from Android is supposedly YUV420P, though I can't verify this until my encoder issues (below) are fixed.
avcodec.avpicture_fill((AVPicture)mFrame, picPointer, avutil.PIX_FMT_YUV420P, VIDEO_WIDTH, VIDEO_HEIGHT)
Problem Now: The line that is supposed to actually encode the data crashes the thread. I get a big native code stack trace that I'm unable to understand. Does anybody have a suggestion?
Here is the code that I am using to instantiate all the ffmpeg libraries:
avcodec.avcodec_register_all();
avcodec.avcodec_init();
avformat.av_register_all();
mCodec = avcodec.avcodec_find_encoder(avcodec.CODEC_ID_H263);
if (mCodec == null)
{
Logging.Log("Unable to find encoder.");
return;
}
Logging.Log("Found encoder.");
mCodecCtx = avcodec.avcodec_alloc_context();
mCodecCtx.bit_rate(300000);
mCodecCtx.codec(mCodec);
mCodecCtx.width(VIDEO_WIDTH);
mCodecCtx.height(VIDEO_HEIGHT);
mCodecCtx.pix_fmt(avutil.PIX_FMT_YUV420P);
mCodecCtx.codec_id(avcodec.CODEC_ID_H263);
mCodecCtx.codec_type(avutil.AVMEDIA_TYPE_VIDEO);
AVRational ratio = new AVRational();
ratio.num(1);
ratio.den(30);
mCodecCtx.time_base(ratio);
mCodecCtx.coder_type(1);
mCodecCtx.flags(mCodecCtx.flags() | avcodec.CODEC_FLAG_LOOP_FILTER);
mCodecCtx.me_cmp(avcodec.FF_LOSS_CHROMA);
mCodecCtx.me_method(avcodec.ME_HEX);
mCodecCtx.me_subpel_quality(6);
mCodecCtx.me_range(16);
mCodecCtx.gop_size(30);
mCodecCtx.keyint_min(10);
mCodecCtx.scenechange_threshold(40);
mCodecCtx.i_quant_factor((float) 0.71);
mCodecCtx.b_frame_strategy(1);
mCodecCtx.qcompress((float) 0.6);
mCodecCtx.qmin(10);
mCodecCtx.qmax(51);
mCodecCtx.max_qdiff(4);
mCodecCtx.max_b_frames(1);
mCodecCtx.refs(2);
mCodecCtx.directpred(3);
mCodecCtx.trellis(1);
mCodecCtx.flags2(mCodecCtx.flags2() | avcodec.CODEC_FLAG2_BPYRAMID | avcodec.CODEC_FLAG2_WPRED | avcodec.CODEC_FLAG2_8X8DCT | avcodec.CODEC_FLAG2_FASTPSKIP);
if (avcodec.avcodec_open(mCodecCtx, mCodec) == 0)
{
Logging.Log("Unable to open encoder.");
return;
}
Logging.Log("Encoder opened.");
mFrameSize = avcodec.avpicture_get_size(avutil.PIX_FMT_YUV420P, VIDEO_WIDTH, VIDEO_HEIGHT);
Logging.Log("Frame size - '" + mFrameSize + "'.");
//mPic = new AVPicture(mPicSize);
mFrame = avcodec.avcodec_alloc_frame();
if (mFrame == null)
{
Logging.Log("Unable to alloc frame.");
}
This is what I want to be able to execute next:
BytePointer picPointer = new BytePointer(data);
int bBuffSize = mFrameSize;
BytePointer bBuffer = new BytePointer(bBuffSize);
int picSize = 0;
if ((picSize = avcodec.avpicture_fill((AVPicture)mFrame, picPointer, avutil.PIX_FMT_YUV420P, VIDEO_WIDTH, VIDEO_HEIGHT)) <= 0)
{
Logging.Log("Couldn't convert preview to AVPicture (" + picSize + ")");
return;
}
Logging.Log("Converted preview to AVPicture (" + picSize + ")");
VCAP_Package vPackage = new VCAP_Package();
if (mCodecCtx.isNull())
{
Logging.Log("Codec Context is null!");
}
//encode the image
int size = avcodec.avcodec_encode_video(mCodecCtx, bBuffer, bBuffSize, mFrame);
int totalSize = 0;
while (size >= 0)
{
totalSize += size;
Logging.Log("Encoded '" + size + "' bytes.");
//Get any delayed frames
size = avcodec.avcodec_encode_video(mCodecCtx, bBuffer, bBuffSize, null);
}
Logging.Log("Finished encoding. (" + totalSize + ")");
But, as of now, I don't know how to put the Bitmap into the right piece or if I have that setup correctly.
A few notes about the code:
- VIDEO_WIDTH = 352
- VIDEO_HEIGHT = 288
- VIDEO_FPS = 30;
回答1:
After a lot of searching, I figured out that you have to load the pointers in a fairly strict and awkward manner. This is how I got everything working:
Codec setup:
avcodec.avcodec_register_all();
avcodec.avcodec_init();
avformat.av_register_all();
/* find the H263 video encoder */
mCodec = avcodec.avcodec_find_encoder(avcodec.CODEC_ID_H263);
if (mCodec == null) {
Log.d("TEST_VIDEO", "avcodec_find_encoder() run fail.");
}
mCodecCtx = avcodec.avcodec_alloc_context();
picture = avcodec.avcodec_alloc_frame();
/* put sample parameters */
mCodecCtx.bit_rate(400000);
/* resolution must be a multiple of two */
mCodecCtx.width(VIDEO_WIDTH);
mCodecCtx.height(VIDEO_HEIGHT);
/* frames per second */
AVRational avFPS = new AVRational();
avFPS.num(1);
avFPS.den(VIDEO_FPS);
mCodecCtx.time_base(avFPS);
mCodecCtx.pix_fmt(avutil.PIX_FMT_YUV420P);
mCodecCtx.codec_id(avcodec.CODEC_ID_H263);
mCodecCtx.codec_type(avutil.AVMEDIA_TYPE_VIDEO);
/* open it */
if (avcodec.avcodec_open(mCodecCtx, mCodec) < 0) {
Log.d("TEST_VIDEO", "avcodec_open() run fail.");
}
/* alloc image and output buffer */
output_buffer_size = 100000;
output_buffer = avutil.av_malloc(output_buffer_size);
size = mCodecCtx.width() * mCodecCtx.height();
picture_buffer = avutil.av_malloc((size * 3) / 2); /* size for YUV 420 */
picture.data(0, new BytePointer(picture_buffer));
picture.data(1, picture.data(0).position(size));
picture.data(2, picture.data(1).position(size / 4));
picture.linesize(0, mCodecCtx.width());
picture.linesize(1, mCodecCtx.width() / 2);
picture.linesize(2, mCodecCtx.width() / 2);
Handling the preview data:
//(1)Convert byte[] first
byte[] data420 = new byte[data.length];
convert_yuv422_to_yuv420(data, data420, VIDEO_WIDTH, VIDEO_HEIGHT);
//(2) Fill picture buffer
int data1_offset = VIDEO_HEIGHT * VIDEO_WIDTH;
int data2_offset = data1_offset * 5 / 4;
int pic_linesize_0 = picture.linesize(0);
int pic_linesize_1 = picture.linesize(1);
int pic_linesize_2 = picture.linesize(2);
//Y
for(y = 0; y < VIDEO_HEIGHT; y++)
{
for(x = 0; x < VIDEO_WIDTH; x++)
{
picture.data(0).put((y * pic_linesize_0 + x), data420[y * VIDEO_WIDTH + x]);
}
}
//Cb and Cr
for(y = 0; y < VIDEO_HEIGHT / 2; y++) {
for(x = 0; x < VIDEO_WIDTH / 2; x++) {
picture.data(1).put((y * pic_linesize_1 + x), data420[data1_offset + y * VIDEO_WIDTH / 2 + x]);
picture.data(2).put((y * pic_linesize_2 + x), data420[data2_offset + y * VIDEO_WIDTH / 2 + x]);
}
}
//(2)Encode
//Encode the image into output_buffer
out_size = avcodec.avcodec_encode_video(mCodecCtx, new BytePointer(output_buffer), output_buffer_size, picture);
Log.d("TEST_VIDEO", "Encoded '" + out_size + "' bytes");
//Delayed frames
for(; out_size > 0; i++) {
out_size = avcodec.avcodec_encode_video(mCodecCtx, new BytePointer(output_buffer), output_buffer_size, null);
Log.d("TEST_VIDEO", "Encoded '" + out_size + "' bytes");
//fwrite(output_buffer, 1, out_size, file);
}
I am still working to packetize the data, but the ongoing test project can be found here @ http://code.google.com/p/test-video-encode/
回答2:
Does android graphics library support the YUV format:
codecCtx.pix_fmt = AVCodecLibrary.PIX_FMT_YUV420P;
See if you can set it to ARGB or RGB32. I know the android graphics library supports this pixel format.
PS: I don't know anything about ffmpeg
来源：https://stackoverflow.com/questions/8515967/encode-video-using-ffmpeg-from-javacv-on-android-causes-native-code-crash