Add (untested) Steam Link video decoding/rendering

app/streaming/video/sl.cpp

@@ -0,0 +1,106 @@
+#include "sl.h"
+
+SLVideoDecoder::SLVideoDecoder()
+    : m_VideoContext(nullptr),
+      m_VideoStream(nullptr)
+{
+
+}
+
+SLVideoDecoder::~SLVideoDecoder()
+{
+    if (m_VideoStream != nullptr) {
+        SLVideo_FreeStream(m_VideoStream);
+    }
+
+    if (m_VideoContext != nullptr) {
+        SLVideo_FreeContext(m_VideoContext);
+    }
+}
+
+bool
+SLVideoDecoder::isHardwareAccelerated()
+{
+    // SLVideo is always hardware accelerated
+    return true;
+}
+
+bool
+SLVideoDecoder::initialize(StreamingPreferences::VideoDecoderSelection vds,
+                           SDL_Window*,
+                           int videoFormat, int, int, int frameRate)
+{
+    // SLVideo only supports hardware decoding
+    if (vds == StreamingPreferences::VDS_FORCE_SOFTWARE) {
+        return false;
+    }
+
+    // SLVideo only supports H.264
+    if (videoFormat != VIDEO_FORMAT_H264) {
+        return false;
+    }
+
+    m_VideoContext = SLVideo_CreateContext();
+    if (!m_VideoContext) {
+        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
+                     "SLVideo_CreateContext() failed");
+        return false;
+    }
+
+    // Create a low latency H.264 stream
+    m_VideoStream = SLVideo_CreateStream(m_VideoContext, k_ESLVideoFormatH264, 1);
+    if (!m_VideoStream) {
+        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
+                     "SLVideo_CreateStream() failed");
+        return false;
+    }
+
+    SLVideo_SetStreamTargetFramerate(m_VideoStream, frameRate, 1);
+
+    return true;
+}
+
+int
+SLVideoDecoder::submitDecodeUnit(PDECODE_UNIT du)
+{
+    int err;
+
+    err = SLVideo_BeginFrame(m_VideoStream, du->fullLength);
+    if (err < 0) {
+        SDL_LogWarn(SDL_LOG_CATEGORY_APPLICATION,
+                    "SLVideo_BeginFrame() failed: %d",
+                    err);
+
+        // Need an IDR frame to resync
+        return DR_NEED_IDR;
+    }
+
+    PLENTRY entry = du->bufferList;
+    while (entry != nullptr) {
+        err = SLVideo_WriteFrameData(m_VideoStream,
+                                     entry->data,
+                                     entry->length);
+        if (err < 0) {
+            SDL_LogWarn(SDL_LOG_CATEGORY_APPLICATION,
+                        "SLVideo_WriteFrameData() failed: %d",
+                        err);
+
+            // Need an IDR frame to resync
+            return DR_NEED_IDR;
+        }
+
+        entry = entry->next;
+    }
+
+    err = SLVideo_SubmitFrame(m_VideoStream);
+    if (err < 0) {
+        SDL_LogWarn(SDL_LOG_CATEGORY_APPLICATION,
+                    "SLVideo_SubmitFrame() failed: %d",
+                    err);
+
+        // Need an IDR frame to resync
+        return DR_NEED_IDR;
+    }
+
+    return DR_OK;
+}