Recherche avancée

Sur d’autres sites (5804)

• avcodec/thread : Don't use ThreadFrame when unnecessary

  6 février 2022, par Andreas Rheinhardt

  avcodec/thread : Don't use ThreadFrame when unnecessary
  The majority of frame-threaded decoders (mainly the intra-only)
  
  need exactly one part of ThreadFrame : The AVFrame. They don't
  
  need the owners nor the progress, yet they had to use it because
  
  ff_thread_(get|release)_buffer() requires it.
  This commit changes this and makes these functions work with ordinary
  
  AVFrames ; the decoders that need the extra fields for progress
  
  use ff_thread_(get|release)_ext_buffer() which work exactly
  
  as ff_thread_(get|release)_buffer() used to do.
  This also avoids some unnecessary allocations of progress AVBuffers,
  
  namely for H.264 and HEVC film grain frames : These frames are not
  
  used for synchronization and therefore don't need a ThreadFrame.
  Also move the ThreadFrame structure as well as ff_thread_ref_frame()
  
  to threadframe.h, the header for frame-threaded decoders with
  
  inter-frame dependencies.
  Reviewed-by : Anton Khirnov <anton@khirnov.net>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/aic.c
  • [DH] libavcodec/alac.c
  • [DH] libavcodec/av1dec.c
  • [DH] libavcodec/av1dec.h
  • [DH] libavcodec/bitpacked_dec.c
  • [DH] libavcodec/cfhd.c
  • [DH] libavcodec/cllc.c
  • [DH] libavcodec/cri.c
  • [DH] libavcodec/dnxhddec.c
  • [DH] libavcodec/dvdec.c
  • [DH] libavcodec/dxtory.c
  • [DH] libavcodec/dxv.c
  • [DH] libavcodec/dxva2_av1.c
  • [DH] libavcodec/error_resilience.h
  • [DH] libavcodec/exr.c
  • [DH] libavcodec/ffv1.h
  • [DH] libavcodec/ffv1dec.c
  • [DH] libavcodec/flacdec.c
  • [DH] libavcodec/fraps.c
  • [DH] libavcodec/h264_picture.c
  • [DH] libavcodec/h264_slice.c
  • [DH] libavcodec/h264dec.c
  • [DH] libavcodec/h264dec.h
  • [DH] libavcodec/hapdec.c
  • [DH] libavcodec/hevc_refs.c
  • [DH] libavcodec/hevcdec.c
  • [DH] libavcodec/hevcdec.h
  • [DH] libavcodec/hqx.c
  • [DH] libavcodec/huffyuvdec.c
  • [DH] libavcodec/jpeg2000dec.c
  • [DH] libavcodec/lagarith.c
  • [DH] libavcodec/lcldec.c
  • [DH] libavcodec/libopenjpegdec.c
  • [DH] libavcodec/magicyuv.c
  • [DH] libavcodec/mdec.c
  • [DH] libavcodec/mpegpicture.h
  • [DH] libavcodec/notchlc.c
  • [DH] libavcodec/nvdec_av1.c
  • [DH] libavcodec/photocd.c
  • [DH] libavcodec/pixlet.c
  • [DH] libavcodec/proresdec2.c
  • [DH] libavcodec/pthread_frame.c
  • [DH] libavcodec/rv34.c
  • [DH] libavcodec/sheervideo.c
  • [DH] libavcodec/takdec.c
  • [DH] libavcodec/thread.h
  • [DH] libavcodec/threadframe.h
  • [DH] libavcodec/tiff.c
  • [DH] libavcodec/tta.c
  • [DH] libavcodec/utils.c
  • [DH] libavcodec/utvideodec.c
  • [DH] libavcodec/v210dec.c
  • [DH] libavcodec/v410dec.c
  • [DH] libavcodec/vaapi_av1.c
  • [DH] libavcodec/vble.c
  • [DH] libavcodec/vp8.h
  • [DH] libavcodec/vp9shared.h
  • [DH] libavcodec/webp.c
  • [DH] libavcodec/ylc.c

• H.264 and VP8 for still image coding : WebP ?

  
  1er octobre 2010, par Dark Shikari — google, H.264, psychovisual optimizations, VP8

  Update : post now contains a Theora comparison as well ; see below.

  JPEG is a very old lossy image format. By today’s standards, it’s awful compression-wise : practically every video format since the days of MPEG-2 has been able to tie or beat JPEG at its own game. The reasons people haven’t switched to something more modern practically always boil down to a simple one — it’s just not worth the hassle. Even if JPEG can be beaten by a factor of 2, convincing the entire world to change image formats after 20 years is nigh impossible. Furthermore, JPEG is fast, simple, and practically guaranteed to be free of any intellectual property worries. It’s been tried before : JPEG-2000 first, then Microsoft’s JPEG XR, both tried to unseat JPEG. Neither got much of anywhere.

  Now Google is trying to dump yet another image format on us, “WebP”. But really, it’s just a VP8 intra frame. There are some obvious practical problems with this new image format in comparison to JPEG ; it doesn’t even support all of JPEG’s features, let alone many of the much-wanted features JPEG was missing (alpha channel support, lossless support). It only supports 4:2:0 chroma subsampling, while JPEG can handle 4:2:2 and 4:4:4. Google doesn’t seem interested in adding any of these features either.

  But let’s get to the meat and see how these encoders stack up on compressing still images. As I explained in my original analysis, VP8 has the advantage of H.264′s intra prediction, which is one of the primary reasons why H.264 has such an advantage in intra compression. It only has i4x4 and i16x16 modes, not i8x8, so it’s not quite as fancy as H.264′s, but it comes close.

  The test files are all around 155KB ; download them for the exact filesizes. For all three, I did a binary search of quality levels to get the file sizes close. For x264, I encoded with --tune stillimage --preset placebo. For libvpx, I encoded with --best. For JPEG, I encoded with ffmpeg, then applied jpgcrush, a lossless jpeg compressor. I suspect there are better JPEG encoders out there than ffmpeg ; if you have one, feel free to test it and post the results. The source image is the 200th frame of Parkjoy, from derf’s page (fun fact : this video was shot here ! More info on the video here.).

  Files : (x264 [154KB], vp8 [155KB], jpg [156KB])

  Results (decoded to PNG) : (x264, vp8, jpg)

  This seems rather embarrassing for libvpx. Personally I think VP8 looks by far the worst of the bunch, despite JPEG’s blocking. What’s going on here ? VP8 certainly has better entropy coding than JPEG does (by far !). It has better intra prediction (JPEG has just DC prediction). How could VP8 look worse ? Let’s investigate.

  VP8 uses a 4×4 transform, which tends to blur and lose more detail than JPEG’s 8×8 transform. But that alone certainly isn’t enough to create such a dramatic difference. Let’s investigate a hypothesis — that the problem is that libvpx is optimizing for PSNR and ignoring psychovisual considerations when encoding the image… I’ll encode with --tune psnr --preset placebo in x264, turning off all psy optimizations. 

  Files : (x264, optimized for PSNR [154KB]) [Note for the technical people : because adaptive quantization is off, to get the filesize on target I had to use a CQM here.]

  Results (decoded to PNG) : (x264, optimized for PSNR)

  What a blur ! Only somewhat better than VP8, and still worse than JPEG. And that’s using the same encoder and the same level of analysis — the only thing done differently is dropping the psy optimizations. Thus we come back to the conclusion I’ve made over and over on this blog — the encoder matters more than the video format, and good psy optimizations are more important than anything else for compression. libvpx, a much more powerful encoder than ffmpeg’s jpeg encoder, loses because it tries too hard to optimize for PSNR.

  These results raise an obvious question — is Google nuts ? I could understand the push for “WebP” if it was better than JPEG. And sure, technically as a file format it is, and an encoder could be made for it that’s better than JPEG. But note the word “could”. Why announce it now when libvpx is still such an awful encoder ? You’d have to be nuts to try to replace JPEG with this blurry mess as-is. Now, I don’t expect libvpx to be able to compete with x264, the best encoder in the world — but surely it should be able to beat an image format released in 1992 ?

  Earth to Google : make the encoder good first, then promote it as better than the alternatives. The reverse doesn’t work quite as well.

  Addendum (added Oct. 2, 03:51) :

  maikmerten gave me a Theora-encoded image to compare as well. Here’s the PNG and the source (155KB). And yes, that’s Theora 1.2 (Ptalarbvorm) beating VP8 handily. Now that is embarassing. Guess what the main new feature of Ptalarbvorm is ? Psy optimizations…

  Addendum (added Apr. 20, 23:33) :

  There’s a new webp encoder out, written from scratch by skal (available in libwebp). It’s significantly better than libvpx — not like that says much — but it should probably beat JPEG much more readily now. The encoder design is rather unique — it basically uses K-means for a large part of the encoding process. It still loses to x264, but that was expected.

  [155KB]

• Updating SDL yuv Texture

  15 juin 2015, par madprogrammer2015

  I am receiving an H.264 video stream and successfully decoding it with FFMPEG. It can display the first frame of data but then after that the screen never updates. It just appears to become a static image. I am using YUV pixel format, and I am receiving it in that format as well. Also I am using SDL_UpdateYUVTexture().

  Here is my code :

  int main()
  
  {
  
      WORD wVersionRequested;
  
      WSADATA wsaData;
  
      int wsaerr;
  
  
  
      if (SDL_Init(SDL_INIT_EVERYTHING)) {
  
          fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError());
  
          exit(1);
  
      }
  
  
  
      // Using MAKEWORD macro, Winsock version request 2.2
  
      wVersionRequested = MAKEWORD(2, 2);
  
  
  
      wsaerr = WSAStartup(wVersionRequested, &wsaData);
  
  
  
      if (wsaerr != 0)
  
      {
  
          /* Tell the user that we could not find a usable */
  
          /* WinSock DLL.*/
  
          printf("The Winsock dll not found!\n");
  
          return 0;
  
      }
  
      else
  
      {
  
          printf("The Winsock dll found!\n");
  
          printf("The status: %s.\n", wsaData.szSystemStatus);
  
      }
  
  
  
      /* Confirm that the WinSock DLL supports 2.2.*/
  
      /* Note that if the DLL supports versions greater    */
  
      /* than 2.2 in addition to 2.2, it will still return */
  
      /* 2.2 in wVersion since that is the version we      */
  
      /* requested.                                        */
  
      if (LOBYTE(wsaData.wVersion) != 2 || HIBYTE(wsaData.wVersion) != 2)
  
      {
  
          /* Tell the user that we could not find a usable */
  
          /* WinSock DLL.*/
  
          printf("The dll do not support the Winsock version %u.%u!\n", LOBYTE(wsaData.wVersion), HIBYTE(wsaData.wVersion));
  
          WSACleanup();
  
          return 0;
  
      }
  
      else
  
      {
  
          printf("The dll supports the Winsock version %u.%u!\n", LOBYTE(wsaData.wVersion), HIBYTE(wsaData.wVersion));
  
          printf("The highest version this dll can support: %u.%u\n", LOBYTE(wsaData.wHighVersion), HIBYTE(wsaData.wHighVersion));
  
      }
  
  
  
      ULONG              localif;
  
      /*INT Ret;
  
      HANDLE ThreadHandle;
  
      DWORD ThreadId;
  
      WSAEVENT AcceptEvent;
  
      char               buf[1024];
  
      int                buflen = 1024, rc, err;*/
  
  
  
      SOCKET s;
  
      SOCKET ns;
  
      SOCKADDR_IN        multi, safrom;
  
      int fromlen;
  
  
  
      int totalSize = 0;
  
  
  
      AVCodec *codec;
  
      AVCodecContext *codecContext;
  
      int frame;
  
      int got_picture;
  
      AVFrame *picture;
  
      AVPacket packet;
  
      SwsContext* convertContext;
  
      uint16_t i = 1;
  
      //std::queue<madproto> queue;
  
      //std::list<madproto> list;
  
      AVCodecParserContext *parser;
  
      std::vector buffer;
  
      //moodycamel::ConcurrentQueue<madproto> protoQueue;
  
  
  
      SDL_Window *window;
  
      SDL_Renderer *renderer;
  
      SDL_Texture *bmp;
  
      SDL_Rect rect;
  
  
  
      file.open("log.txt");
  
  
  
      s = socket(AF_INET, SOCK_STREAM, IPPROTO_RM);
  
  
  
      multi.sin_family = AF_INET;
  
      multi.sin_port = htons(5150);
  
      multi.sin_addr.s_addr = inet_addr("234.5.6.7");
  
      int bindResult = bind(s, (PSOCKADDR)&amp;multi, sizeof(multi));
  
  
  
      if (bindResult &lt; 0)
  
      {
  
          std::cout &lt;&lt; "bindResult: " &lt;&lt; WSAGetLastError() &lt;&lt; std::endl;
  
      }
  
  
  
      listen(s, 10);
  
  
  
      //if ((AcceptEvent = WSACreateEvent()) == WSA_INVALID_EVENT)
  
      //{
  
      //  printf("WSACreateEvent() failed with error %d\n", WSAGetLastError());
  
      //  return 1;
  
      //}
  
      //else
  
      //  printf("WSACreateEvent() is OK!\n");
  
  
  
      //// Create a worker thread to service completed I/O requests
  
      //if ((ThreadHandle = CreateThread(NULL, 0, WorkerThread, (LPVOID)AcceptEvent, 0, &amp;ThreadId)) == NULL)
  
      //{
  
      //  printf("CreateThread() failed with error %d\n", GetLastError());
  
      //  return 1;
  
      //}
  
      //else
  
      //  printf("CreateThread() should be fine!\n");
  
  
  
      localif = inet_addr("192.168.1.2");
  
      setsockopt(s, IPPROTO_RM, RM_ADD_RECEIVE_IF, (char *)&amp;localif, sizeof(localif));
  
  
  
      fromlen = sizeof(safrom);
  
      ns = accept(s, (SOCKADDR *)&amp;safrom, &amp;fromlen);
  
  
  
      closesocket(s);  // Don't need to listen anymore
  
  
  
      std::string received;
  
  
  
      av_register_all();
  
  
  
      int horizontal = 0;
  
      int vertical = 0;
  
  
  
      GetDesktopResolution(horizontal, vertical);
  
  
  
      codec = avcodec_find_decoder(CODEC_ID_H264);
  
      if (!codec) {
  
          std::cout &lt;&lt; "codec not found" &lt;&lt; std::endl;
  
          std::cin.get();
  
      }
  
  
  
      codecContext = avcodec_alloc_context3(codec);
  
  
  
      /*if (codec->capabilities &amp; CODEC_CAP_TRUNCATED)
  
          codecContext->flags |= CODEC_FLAG_TRUNCATED;*/
  
  
  
      //codecContext->flags |= CODEC_FLAG_LOW_DELAY;
  
      codecContext->flags2 |= CODEC_FLAG2_CHUNKS;
  
  
  
      codecContext->width = horizontal;
  
      codecContext->height = vertical;
  
      codecContext->codec_id = CODEC_ID_H264;
  
      codecContext->codec_type = AVMEDIA_TYPE_VIDEO;
  
      codecContext->pix_fmt = PIX_FMT_YUV420P;
  
      codecContext->thread_type = 0;
  
  
  
      if (avcodec_open2(codecContext, codec, NULL) &lt; 0) {
  
          std::cout &lt;&lt; "could not open codec" &lt;&lt; std::endl;
  
          std::cin.get();
  
      }
  
  
  
      convertContext = sws_getContext(
  
          codecContext->width,
  
          codecContext->height,
  
          PIX_FMT_RGB32,
  
          codecContext->width,
  
          codecContext->height,
  
          PIX_FMT_YUV420P,
  
          SWS_BICUBIC,
  
          NULL,
  
          NULL,
  
          NULL
  
          );
  
  
  
      parser = av_parser_init(CODEC_ID_H264);
  
  
  
      picture = av_frame_alloc();
  
  
  
      if (ns == INVALID_SOCKET)
  
      {
  
          std::cout &lt;&lt; "accept didn't work!" &lt;&lt; std::endl;
  
          std::cin.get();
  
      }
  
  
  
      /*if (WSASetEvent(AcceptEvent) == FALSE)
  
      {
  
          printf("WSASetEvent() failed with error %d\n", WSAGetLastError());
  
          return 1;
  
      }
  
      else
  
          printf("WSASetEvent() should be working!\n");*/
  
  
  
      window = SDL_CreateWindow("YUV", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, codecContext->width, codecContext->height, SDL_WINDOW_SHOWN);
  
      renderer = SDL_CreateRenderer(window, -1, 0);
  
      bmp = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_IYUV, SDL_TEXTUREACCESS_STREAMING, codecContext->width, codecContext->height);
  
  
  
      //receive = SDL_CreateThread(receiveThread, "ReceiveThread", (void *)NULL);
  
      bool quit = false;
  
  
  
      rect.x = 0;
  
      rect.y = 0;
  
      rect.w = codecContext->width;
  
      rect.h = codecContext->height;
  
  
  
      while (!quit)
  
      {
  
          while (true)
  
          {
  
              MadProto proto;
  
              int result = recvfrom(ns, (char *)&amp;proto, sizeof(MadProto), 0, (struct sockaddr *)&amp;multi, &amp;fromlen);
  
  
  
              if (result &lt; 0)
  
              {
  
                  std::cout &lt;&lt; "receive failed! error: " &lt;&lt; WSAGetLastError() &lt;&lt; std::endl;
  
                  break;
  
              }
  
              else
  
              {
  
                  std::cout &lt;&lt; "receive successful, received " &lt;&lt; result &lt;&lt; " bytes" &lt;&lt; std::endl;
  
  
  
                  if (ntohs(proto.frame_end) == 1)
  
                  {
  
                      uint8_t *outbuffer = NULL;
  
                      int outBufSize = 0;
  
                      int rc = av_parser_parse2(parser, codecContext, &amp;outbuffer, &amp;outBufSize, buffer.data(), buffer.size(), 0, 0, 0);
  
  
  
                      if (outBufSize &lt;= 0)
  
                      {
  
                          std::cout &lt;&lt; "parsing failed!" &lt;&lt; std::endl;
  
                          std::cout &lt;&lt; "outBufSize: " &lt;&lt; outBufSize &lt;&lt; std::endl;
  
                          break;
  
                      }
  
  
  
                      if (rc)
  
                      {
  
                          std::cout &lt;&lt; "rc: " &lt;&lt; rc &lt;&lt; std::endl;
  
                          std::cout &lt;&lt; "parsing successful!" &lt;&lt; std::endl;
  
                          //std::cin.get();
  
  
  
                          av_init_packet(&amp;packet);
  
                          packet.size = outBufSize;
  
                          packet.data = outbuffer;
  
  
  
                          frame = avcodec_decode_video2(codecContext, picture, &amp;got_picture, &amp;packet);
  
  
  
                          if (frame &lt; 0)
  
                          {
  
                              std::cout &lt;&lt; "decoding was unsuccessful!" &lt;&lt; std::endl;
  
                              break;
  
                          }
  
  
  
                          if (got_picture)
  
                          {
  
                              std::cout &lt;&lt; "decoding was successful!" &lt;&lt; std::endl;
  
                              std::cout &lt;&lt; "decoded length was: " &lt;&lt; frame &lt;&lt; std::endl;
  
                              buffer.empty();
  
  
  
                              //std::cin.get();
  
                              int code = SDL_UpdateYUVTexture(bmp, NULL, picture->data[0], picture->linesize[0],
  
                                  picture->data[1], picture->linesize[1],
  
                                  picture->data[2], picture->linesize[2]);
  
  
  
                              if (code &lt; 0)
  
                              {
  
                                  std::cout &lt;&lt; "unable to update texture " &lt;&lt; SDL_GetError() &lt;&lt; std::endl;
  
                                  std::cin.get();
  
                              }
  
  
  
                              code = SDL_RenderClear(renderer);
  
  
  
                              if (code &lt; 0)
  
                              {
  
                                  std::cout &lt;&lt; "renderer clear failed " &lt;&lt; SDL_GetError() &lt;&lt; std::endl;
  
                                  std::cin.get();
  
                              }
  
  
  
                              code = SDL_RenderCopy(renderer, bmp, NULL, &amp;rect);
  
  
  
                              if (code &lt; 0)
  
                              {
  
                                  std::cout &lt;&lt; "renderer copy failed " &lt;&lt; SDL_GetError() &lt;&lt; std::endl;
  
                                  std::cin.get();
  
                              }
  
  
  
                              SDL_RenderPresent(renderer);
  
  
  
                              SDL_Delay(40);
  
                          }
  
  
  
                          av_free_packet(&amp;packet);
  
                      }
  
                  }
  
                  else
  
                  {
  
                      std::copy(proto.payload, proto.payload + ntohs(proto.nal_length), std::back_inserter(buffer));
  
                      std::cout &lt;&lt; "frame is continuing!" &lt;&lt; std::endl;
  
  
  
                      //queue.push(proto);
  
                      //list.push_front(proto);
  
                  }
  
              }
  
          }
  
  
  
          SDL_WaitEvent(&amp;event);
  
          switch (event.type)
  
          {
  
          case SDL_QUIT:
  
              quit = true;
  
              break;
  
          }
  
      }
  
  
  
      std::cout &lt;&lt; "closing everything!" &lt;&lt; std::endl;
  
      av_frame_free(&amp;picture);
  
      closesocket(ns);
  
      fclose(f);
  
      std::cin.get();
  
      return 0;
  
  }
  
  </madproto></madproto></madproto>