[Libva] encode surfaces created from prime fd (backed by OpenGL 2D texture)

[Yuan, Shengquan]

For vaCreateContext, I think render_targets/num_render_targets are optional (it depends on driver implementation), and the surface of vaBeginPicture can a brand-new surface
VAStatus vaCreateContext (
    VADisplay dpy,
    VAConfigID config_id,
    int picture_width,
    int picture_height,
    int flag,
    VASurfaceID *render_targets,
    int num_render_targets,
    VAContextID *context                /* out */
);

DMA buffer can be imported through VA_SURFACE_ATTRIB_MEM_TYPE_DRM_PRIME, e.g.
    VASurfaceAttribExternalBuffers buf;
    VASurfaceAttribType type,
    VASurfaceAttrib attrib_list[2]
    unsigned long prime_fd; /* an input variable, it is the imported prime fd from other process */

    int stride = frame_width_aligned, height_aligned = frame_height_aligned;

    if (stride == 0)
        stride = frame_width_mbaligned;
    if (height_aligned == 0)
        height_aligned = frame_height_mbaligned;

    buf.pixel_format = VA_FOURCC_NV12;
    buf.width = frame_width_mbaligned;
    buf.height = frame_height_mbaligned;
    buf.data_size = stride * height_aligned * 1.5;
    buf.num_buffers = 1; /* import only 1 buffer */
    buf.num_planes = 3;
    buf.pitches[0] = stride;
    buf.pitches[1] = stride;
    buf.pitches[2] = stride;
    buf.pitches[3] = 0;
    buf.offsets[0] = 0;
    buf.offsets[1] = stride * height_aligned;
    buf.offsets[2] = buf.offsets[1];
    buf.offsets[3] = 0;
    buf.buffers = &prime_fd;
    buf.flags = 0;
    buf.private_data = NULL;

    attrib_list[0].type = (VASurfaceAttribType)VASurfaceAttribMemoryType;
    attrib_list[0].flags = VA_SURFACE_ATTRIB_SETTABLE;
    attrib_list[0].value.type = VAGenericValueTypeInteger;
    attrib_list[0].value.value.i = VA_SURFACE_ATTRIB_MEM_TYPE_DRM_PRIME

    attrib_list[1].type = (VASurfaceAttribType)VASurfaceAttribExternalBufferDescriptor;
    attrib_list[1].flags = VA_SURFACE_ATTRIB_SETTABLE;
    attrib_list[1].value.type = VAGenericValueTypePointer;
attrib_list[1].value.value.p = (void *)buf;
vaCreateSurfaces(
            va_dpy,
            VA_RT_FORMAT_YUV420,
            frame_width_mbaligned, frame_height_mbaligned,
            &surface_id, 1,
            &attrib_list, 2);


From: Libva [mailto:libva-bounces at lists.freedesktop.org] On Behalf Of Anon
Sent: Wednesday, May 25, 2016 2:23 PM
To: libva at lists.freedesktop.org
Subject: [Libva] encode surfaces created from prime fd (backed by OpenGL 2D texture)

Hi All,

I want to implement the following use case on Intel Haswell CPU with HD graphics:

offscreen OpenGL rendering to OpenGL 2D texture -> use EGL_MESA_image_dma_buf_export to export the texture as prime fd -> vaCreateSurfaces from the prime fd -> use vaapi to hw acclerate h264 encoding

Is this supported by the latest va-api and libva-intel-driver release (i.e., 1.7.0)? If so, is there any example I can start with?

I did read the sample application h264encode.c and thought it might be a good starting point. However, the first major issue I encountered is when creating context through vaCreateContext, a number of pre-allocated va surfaces are required and thus statically associated with the new va context. However, with prime fd, the fd will change so a new va surface is created with every new prime fd. I don't see any API can be used to dynamically add/remove va surfaces after the context is created. Can you please give me some suggestions?

Best,
Kristine
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