I want to make .avi video file from bitmap images by using c++ code. I wrote the following code:
//Get RGB array data from bmp file uint8_t* rgb24Data = new uint8_t[3*imgWidth*imgHeight]; hBitmap = (HBITMAP) LoadImage( NULL, _T("myfile.bmp"), IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE); GetDIBits(hdc, hBitmap, 0, imgHeight, rgb24Data , (BITMAPINFO*)&bmi, DIB_RGB_COLORS); /* Allocate the encoded raw picture. */ AVPicture dst_picture; avpicture_alloc(&dst_picture, AV_PIX_FMT_YUV420P, imgWidth, imgHeight); /* Convert rgb24Data to YUV420p and stored into array dst_picture.data */ RGB24toYUV420P(imgWidth, imgHeight, rgb24Data, dst_picture.data); //How to implement this function? //code for encode frame dst_picture here
My problem is how to implement RGB24toYUV420P() function, this function will convert RGB24 data from array rgb24Data to YUV420p and store into array dst_picture.data for ffmpeg encoder?
You can use the SwScale
Something like this:
#include SwsContext * ctx = sws_getContext(imgWidth, imgHeight, AV_PIX_FMT_RGB24, imgWidth, imgHeight, AV_PIX_FMT_YUV420P, 0, 0, 0, 0); uint8_t * inData[1] = { rgb24Data }; // RGB24 have one plane int inLinesize[1] = { 3*imgWidth }; // RGB stride sws_scale(ctx, inData, inLinesize, 0, imgHeight, dst_picture.data, dst_picture.linesize)
Note that you should create an instance of the SwsContext object only once, not for each frame.
Runnable example on FFmpeg 2.7.6
This answer got me on the right path, but:
- the API changed slightly since:
SwsContext * must be struct SwsContext * instead - I wanted a minimal runnable example to test it out
The example synthesizes and encodes some colorful frames generated by generate_rgb.
ffmpeg_encoder_set_frame_yuv_from_rgb does the RGB24 to YUV conversion.
Preview of generated output.
#include #include #include #include static AVCodecContext *c = NULL; static AVFrame *frame; static AVPacket pkt; static FILE *file; struct SwsContext *sws_context = NULL; static void ffmpeg_encoder_set_frame_yuv_from_rgb(uint8_t *rgb) { const int in_linesize[1] = { 3 * c->width }; sws_context = sws_getCachedContext(sws_context, c->width, c->height, AV_PIX_FMT_RGB24, c->width, c->height, AV_PIX_FMT_YUV420P, 0, 0, 0, 0); sws_scale(sws_context, (const uint8_t * const *)&rgb, in_linesize, 0, c->height, frame->data, frame->linesize); } uint8_t* generate_rgb(int width, int height, int pts, uint8_t *rgb) { int x, y, cur; rgb = realloc(rgb, 3 * sizeof(uint8_t) * height * width); for (y = 0; y pts / 25) % 2 == 0) { if (y bit_rate = 400000; c->width = width; c->height = height; c->time_base.num = 1; c->time_base.den = fps; c->gop_size = 10; c->max_b_frames = 1; c->pix_fmt = AV_PIX_FMT_YUV420P; if (codec_id == AV_CODEC_ID_H264) av_opt_set(c->priv_data, "preset", "slow", 0); if (avcodec_open2(c, codec, NULL) format = c->pix_fmt; frame->width = c->width; frame->height = c->height; ret = av_image_alloc(frame->data, frame->linesize, c->width, c->height, c->pix_fmt, 32); if (ret data[0]); av_frame_free(&frame); } /* Encode one frame from an RGB24 input and save it to the output file. Must be called after ffmpeg_encoder_start, and ffmpeg_encoder_finish must be called after the last call to this function. */ void ffmpeg_encoder_encode_frame(uint8_t *rgb) { int ret, got_output; ffmpeg_encoder_set_frame_yuv_from_rgb(rgb); av_init_packet(&pkt); pkt.data = NULL; pkt.size = 0; ret = avcodec_encode_video2(c, &pkt, frame, &got_output); if (ret pts = pts; rgb = generate_rgb(width, height, pts, rgb); ffmpeg_encoder_encode_frame(rgb); } ffmpeg_encoder_finish(); free(rgb); } int main(void) { avcodec_register_all(); encode_example("tmp.h264", AV_CODEC_ID_H264); encode_example("tmp.mpg", AV_CODEC_ID_MPEG1VIDEO); /* TODO: is this encoded correctly? Possible to view it without container? */ /*encode_example("tmp.vp8", AV_CODEC_ID_VP8);*/ return 0; }
Tested on Ubuntu 15.10. Code on GitHub.
