H264 YUV420视频翻转

h264解码后视频翻转，基于SDL overlay.

翻转YUV420：

 

void TurnPlanar(const unsigned char *srcp_y, unsigned char *dstp_y,  const unsigned char *srcp_u, unsigned char *dstp_u,  const unsigned char *srcp_v, unsigned char *dstp_v,  const int rowsize, const int height,  const int rowsizeUV, const int heightUV,  const int src_pitch_y, const int dst_pitch_y,  const int src_pitch_u, const int dst_pitch_uv,  const int src_pitch_v, const int direction){/*++++++++++++++++++++++++++++++++++++++++++(0,0)************************>x******>y++++++++++++++++++++++++++++++++++++++++++++*/int y, x, offset;if (direction == 1) // Right{for(y=0; y<height; y++){offset = height-1-y;for (x=0; x<rowsize; x++){dstp_y[offset] = srcp_y[x];offset += dst_pitch_y;}srcp_y += src_pitch_y;}for(y=0; y<heightUV; y++){offset = heightUV-1-y;for (x=0; x<rowsizeUV; x++){dstp_u[offset] = srcp_u[x];dstp_v[offset] = srcp_v[x];offset += dst_pitch_uv;}srcp_u += src_pitch_u;srcp_v += src_pitch_v;}}else if (direction == -1) // Left{srcp_y += rowsize-1;for(y=0; y<height; y++){offset = y;for (x=0; x<rowsize; x++){dstp_y[offset] = srcp_y[-x];offset += dst_pitch_y;}srcp_y += src_pitch_y;}srcp_u += rowsizeUV-1;srcp_v += rowsizeUV-1;for(y=0; y<heightUV; y++){offset = y;for (x=0; x<rowsizeUV; x++){dstp_u[offset] = srcp_u[-x];dstp_v[offset] = srcp_v[-x];offset += dst_pitch_uv;}srcp_u += src_pitch_u;srcp_v += src_pitch_v;}}else // 180{dstp_y += (height-1)*dst_pitch_y + (rowsize-1);for (y = 0; y<height; y++) {for (x = 0; x<rowsize; x++) {dstp_y[-x] = srcp_y[x];}dstp_y -= dst_pitch_y;srcp_y += src_pitch_y;}dstp_u += (heightUV-1)*dst_pitch_uv + (rowsizeUV-1);dstp_v += (heightUV-1)*dst_pitch_uv + (rowsizeUV-1);for (y = 0; y<heightUV; y++) {for (x = 0; x<rowsizeUV; x++) {dstp_u[-x] = srcp_u[x];dstp_v[-x] = srcp_v[x];}dstp_u -= dst_pitch_uv;dstp_v -= dst_pitch_uv;srcp_u += src_pitch_u;srcp_v += src_pitch_v;}}}

应用部分：

在设置编码参数时。如果侧翻，需要将width 和 height互换

pImg_convert_ctx = sws_getContext(FrameData.width,FrameData.height, FrameData.pix_fmt ,\FrameData.height, FrameData.width, PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);

 

AVPicture *pict = new AVPicture;pict->data[0] = bmp->pixels[0];pict->data[1] = bmp->pixels[2];pict->data[2] = bmp->pixels[1];pict->linesize[0] = bmp->pitches[0];pict->linesize[1] = bmp->pitches[2];pict->linesize[2] = bmp->pitches[1];// Convert the image into YUV format that SDL usesint nScale = sws_scale(pImg_convert_ctx, ((AVPicture *)FrameData.pFrame)->data, ((AVPicture *)FrameData.pFrame)->linesize,\                   0, FrameData.height, picttmp->data, picttmp->linesize);int pitch, pitchUV, align;align = screen->format->BitsPerPixel;pitch = (FrameData.width + align - 1)/align*align;pitchUV = (pitch+1)>>1;TurnPlanar(picttmp->data[0], pict->data[0], picttmp->data[1], pict->data[1], picttmp->data[2], pict->data[2],\FrameData.height, FrameData.width, FrameData.height/2, FrameData.width/2,\pitch, pitch, pitchUV, pitchUV, pitchUV, 1);//侧翻

 效果如下：