我正在尝试将一系列图像编码成一个视频文件。我正在使用api-example.c中的代码，它可以工作，但是在视频中给我奇怪的绿色。我知道，我需要将我的RGB图像转换为YUV，我找到了一些解决方案，但它们不起作用，颜色不是绿色而是非常奇怪的，所以这是代码：
// Register all formats and codecs
av_register_all();
AVCodec *codec;
AVCodecContext *c= NULL;
int i, out_size, size, outbuf_size;
FILE *f;
AVFrame *picture;
uint8_t *outbuf;
printf("Video encoding\n");
/* find the mpeg video encoder */
codec = avcodec_find_encoder(CODEC_ID_MPEG2VIDEO);
if (!codec) {
fprintf(stderr, "codec not found\n");
exit(1);
}
c= avcodec_alloc_context();
picture= avcodec_alloc_frame();
/* put sample parameters */
c->bit_rate = 400000;
/* resolution must be a multiple of two */
c->width = 352;
c->height = 288;
/* frames per second */
c->time_base= (AVRational){1,25};
c->gop_size = 10; /* emit one intra frame every ten frames */
c->max_b_frames=1;
c->pix_fmt = PIX_FMT_YUV420P;
/* open it */
if (avcodec_open(c, codec) < 0) {
fprintf(stderr, "could not open codec\n");
exit(1);
}
f = fopen(filename, "wb");
if (!f) {
fprintf(stderr, "could not open %s\n", filename);
exit(1);
}
/* alloc image and output buffer */
outbuf_size = 100000;
outbuf = malloc(outbuf_size);
size = c->width * c->height;
#pragma mark -
AVFrame* outpic = avcodec_alloc_frame();
int nbytes = avpicture_get_size(PIX_FMT_YUV420P, c->width, c->height);
//create buffer for the output image
uint8_t* outbuffer = (uint8_t*)av_malloc(nbytes);
#pragma mark -
for(i=1;i<77;i++) {
fflush(stdout);
int numBytes = avpicture_get_size(PIX_FMT_YUV420P, c->width, c->height);
uint8_t *buffer = (uint8_t *)av_malloc(numBytes*sizeof(uint8_t));
UIImage *image = [UIImage imageNamed:[NSString stringWithFormat:@"10%d", i]];
CGImageRef newCgImage = [image CGImage];
CGDataProviderRef dataProvider = CGImageGetDataProvider(newCgImage);
CFDataRef bitmapData = CGDataProviderCopyData(dataProvider);
buffer = (uint8_t *)CFDataGetBytePtr(bitmapData);
avpicture_fill((AVPicture*)picture, buffer, PIX_FMT_RGB8, c->width, c->height);
avpicture_fill((AVPicture*)outpic, outbuffer, PIX_FMT_YUV420P, c->width, c->height);
struct SwsContext* fooContext = sws_getContext(c->width, c->height,
PIX_FMT_RGB8,
c->width, c->height,
PIX_FMT_YUV420P,
SWS_FAST_BILINEAR, NULL, NULL, NULL);
//perform the conversion
sws_scale(fooContext, picture->data, picture->linesize, 0, c->height, outpic->data, outpic->linesize);
// Here is where I try to convert to YUV
/* encode the image */
out_size = avcodec_encode_video(c, outbuf, outbuf_size, outpic);
printf("encoding frame %3d (size=%5d)\n", i, out_size);
fwrite(outbuf, 1, out_size, f);
free(buffer);
buffer = NULL;
}
/* get the delayed frames */
for(; out_size; i++) {
fflush(stdout);
out_size = avcodec_encode_video(c, outbuf, outbuf_size, NULL);
printf("write frame %3d (size=%5d)\n", i, out_size);
fwrite(outbuf, 1, outbuf_size, f);
}
/* add sequence end code to have a real mpeg file */
outbuf[0] = 0x00;
outbuf[1] = 0x00;
outbuf[2] = 0x01;
outbuf[3] = 0xb7;
fwrite(outbuf, 1, 4, f);
fclose(f);
free(outbuf);
avcodec_close(c);
av_free(c);
av_free(picture);
printf("\n");
请给我建议如何解决这个问题。