Hello all,
I need help in understanding what I am doing wrong in a section of which
takes a pixel array encoded as RGB24 from SDL2 and making it work with
h.264 encoding. I am converting to YUV format via sw_scale(), but still
no luck.
Input: RGB24 encoded array as used in SDL2's SDL_Surface with dimension
256 width by 144 height
Output: H.264 video with dimension 256 by 144
void *encodeToVideo(void *ignore){
AVCodec *codec;
AVCodecContext *c= NULL;
int i, ret, got_output;
AVFrame *_frame;
AVPacket pkt;
uint8_t endcode[] = { 0, 0, 1, 0xb7 };
i = 0;
queue<SDL_Surface*> freeLater;
/* find the video encoder */
avcodec_register_all();
codec = avcodec_find_encoder(AV_CODEC_ID_H264);
if (!codec) {
fprintf(stderr, "Codec not found\n");
exit(1);
}
c = avcodec_alloc_context3(codec);
if (!c) {
fprintf(stderr, "Could not allocate video codec context\n");
exit(1);
}
/* put sample parameters */
c->bit_rate = 400000;
c->width = 256;
c->height = 144;
/* frames per second */
c->time_base = (AVRational){1,30};
/* emit one intra frame every frames*/
c->gop_size = 1;
c->max_b_frames = 0;
c->pix_fmt = AV_PIX_FMT_YUV420P;
av_opt_set(c->priv_data, "zerolatency", "veryfast", 0);
/* open codec */
if (avcodec_open2(c, codec, NULL) < 0) {
fprintf(stderr, "Could not open codec\n");
exit(1);
}
_frame = av_frame_alloc();
if (!_frame) {
fprintf(stderr, "Could not allocate video frame\n");
exit(1);
}
_frame->format = c->pix_fmt;
_frame->width = c->width;
_frame->height = c->height;
/* the image can be allocated by any means and av_image_alloc() is
* just the most convenient way if av_malloc() is to be used */
ret = av_image_alloc(_frame->data, _frame->linesize, c->width,
c->height,
c->pix_fmt, 32);
if (ret < 0) {
fprintf(stderr, "Could not allocate raw picture buffer\n");
exit(1);
}
while(!renderFramesDone || !renderFramesOut->empty()){
if(renderFramesOut->empty()) continue;
SDL_Surface *imageToEncode = renderFramesOut->front();
renderFramesOut->pop();
freeLater.push(imageToEncode);
av_init_packet(&pkt);
pkt.data = NULL; // packet data will be allocated by the encoder
pkt.size = 0;
fflush(stdout);
struct SwsContext* convertCtx;
convertCtx = sws_getContext(256, 144, AV_PIX_FMT_RGB24,
256, 144, AV_PIX_FMT_YUV420P, 0, 0,
0, 0);
uint8_t *inData[1] = {(uint8_t *)(imageToEncode->pixels)};
int inLinesize[1] = { 256 };
sws_scale(convertCtx, inData, inLinesize, 0, 144, _frame->data,
_frame->linesize);
sws_freeContext(convertCtx);
_frame->pts = i++;
/* encode the image */
ret = avcodec_encode_video2(c, &pkt, _frame, &got_output);
if (ret < 0) {
fprintf(stdout, "Error encoding frame\n");
exit(1);
}
if(got_output){
fflush(stdout);
fwrite(pkt.data, 1, pkt.size, stdout);
av_packet_unref(&pkt);
}
}
/* get the delayed frames */
for (got_output = 1; got_output; i++) {
fflush(stdout);
ret = avcodec_encode_video2(c, &pkt, NULL, &got_output);
if (ret < 0) {
fprintf(stderr, "Error encoding frame\n");
exit(1);
}
if (got_output) {
fprintf(stderr, "Write frame %3d (size=%5d)\n", i, pkt.size);
fwrite(pkt.data, 1, pkt.size, stdout);
av_packet_unref(&pkt);
}
}
/* add sequence end code to have a real mpeg file */
fwrite(endcode, 1, sizeof(endcode), stdout);
fclose(stdout);
avcodec_close(c);
av_free(c);
av_freep(_frame->data);
av_frame_free(&_frame);
while(!freeLater.empty()){
SDL_FreeSurface(freeLater.front());
freeLater.pop();
}
encodeToVideoDone = true;
return NULL;
}
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