Support decoding FFmpeg via VDPAU.

This fixes a bug where we hit the VAAPI-by-VDPAU emulation,
which is seemingly bad and just hangs.

Note that this means that if you have a VDPAU card with worse
format support than your VA-API card, you'll now lose some formats.

diff --git a/nageru/ffmpeg_capture.cpp b/nageru/ffmpeg_capture.cpp
index d1b7e74102d623b54ac35c2c4ba8bc6dc6d1cb24..0dea5598555921c401d8e3d463796dc3edaad9f6 100644 (file)
--- a/nageru/ffmpeg_capture.cpp
+++ b/nageru/ffmpeg_capture.cpp
@@ -454,7 +454,8 @@ void FFmpegCapture::send_disconnected_frame()
        }
 }
 
-AVPixelFormat get_vaapi_hw_format(AVCodecContext *ctx, const AVPixelFormat *fmt)
+template<AVHWDeviceType type>
+AVPixelFormat get_hw_format(AVCodecContext *ctx, const AVPixelFormat *fmt)
 {
        for (const AVPixelFormat *fmt_ptr = fmt; *fmt_ptr != -1; ++fmt_ptr) {
                for (int i = 0;; ++i) {  // Termination condition inside loop.
@@ -464,7 +465,7 @@ AVPixelFormat get_vaapi_hw_format(AVCodecContext *ctx, const AVPixelFormat *fmt)
                                break;
                        }
                        if (config->methods & AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX &&
-                           config->device_type == AV_HWDEVICE_TYPE_VAAPI &&
+                           config->device_type == type &&
                            config->pix_fmt == *fmt_ptr) {
                                return config->pix_fmt;
                        }
@@ -544,14 +545,24 @@ bool FFmpegCapture::play_video(const string &pathname)
        }
 
        // Seemingly, it's not too easy to make something that just initializes
-       // “whatever goes”, so we don't get VDPAU or CUDA here without enumerating
-       // through several different types. VA-API will do for now.
+       // “whatever goes”, so we don't get CUDA or VULKAN or whatever here
+       // without enumerating through several different types.
+       // VA-API and VDPAU will do for now. We prioritize VDPAU for the
+       // simple reason that there's a VA-API-via-VDPAU emulation for NVidia
+       // cards that seems to work, but just hangs when trying to transfer the frame.
+       //
+       // Note that we don't actually check codec support beforehand,
+       // so if you have a low-end VDPAU device but a high-end VA-API device,
+       // you lose out on the extra codec support from the latter.
        AVBufferRef *hw_device_ctx = nullptr;
-       if (av_hwdevice_ctx_create(&hw_device_ctx, AV_HWDEVICE_TYPE_VAAPI, nullptr, nullptr, 0) < 0) {
-               fprintf(stderr, "Failed to initialize VA-API for FFmpeg acceleration. Decoding video in software.\n");
-       } else {
+       if (av_hwdevice_ctx_create(&hw_device_ctx, AV_HWDEVICE_TYPE_VDPAU, nullptr, nullptr, 0) >= 0) {
+               video_codec_ctx->hw_device_ctx = av_buffer_ref(hw_device_ctx);
+               video_codec_ctx->get_format = get_hw_format<AV_HWDEVICE_TYPE_VDPAU>;
+       } else if (av_hwdevice_ctx_create(&hw_device_ctx, AV_HWDEVICE_TYPE_VAAPI, nullptr, nullptr, 0) >= 0) {
                video_codec_ctx->hw_device_ctx = av_buffer_ref(hw_device_ctx);
-               video_codec_ctx->get_format = get_vaapi_hw_format;
+               video_codec_ctx->get_format = get_hw_format<AV_HWDEVICE_TYPE_VAAPI>;
+       } else {
+               fprintf(stderr, "Failed to initialize VA-API or VDPAU for FFmpeg acceleration. Decoding video in software.\n");
        }
 
        if (avcodec_open2(video_codec_ctx.get(), video_codec, nullptr) < 0) {
@@ -899,7 +910,8 @@ AVFrameWithDeleter FFmpegCapture::decode_frame(AVFormatContext *format_ctx, AVCo
                // Decode video, if we have a frame.
                int err = avcodec_receive_frame(video_codec_ctx, video_avframe.get());
                if (err == 0) {
-                       if (video_avframe->format == AV_PIX_FMT_VAAPI) {
+                       if (video_avframe->format == AV_PIX_FMT_VAAPI ||
+                           video_avframe->format == AV_PIX_FMT_VDPAU) {
                                // Get the frame down to the CPU. (TODO: See if we can keep it
                                // on the GPU all the way, since it will be going up again later.
                                // However, this only works if the OpenGL GPU is the same one.)