get_frame_pixels()

std::span< const uint8_t > MayaFlux::Kakshya::VideoStreamContainer::get_frame_pixels

(

uint64_t

frame_index

)

const

Get raw pixel data for a single frame as a byte span.

Parameters

frame_index

Zero-based frame index.

Returns

Span of pixel bytes for the frame, empty if out of range.

Definition at line 238 of file VideoStreamContainer.cpp.

{
    const size_t frame_bytes = get_frame_byte_size();
    if (frame_bytes == 0 || frame_index >= m_num_frames)
        return {};
 
    if (m_ring_capacity == 0) {
        std::span<const uint8_t> result;
        seqlock_read_void(m_data_lock, 8, [&] {
            if (m_data.empty())
                return;
 
            auto [ptr, bytes] = variant_bytes(m_data[0]);
            if (!ptr)
                return;
 
            const size_t offset = frame_index * frame_bytes;
            if (offset + frame_bytes > bytes)
                return;
 
            result = { ptr + offset, frame_bytes };
        });
        return result;
    }
 
    const uint32_t slot = slot_for(frame_index);
    if (m_slot_frame[slot].load(std::memory_order_acquire) == frame_index) {
        if (m_data.empty())
            return {};
 
        auto [ptr, bytes] = variant_bytes(m_data[0]);
        if (!ptr)
            return {};
 
        const size_t offset = static_cast<size_t>(slot) * frame_bytes;
        if (offset + frame_bytes > bytes)
            return {};
 
        return { ptr + offset, frame_bytes };
    }
 
    return {};
}

References get_frame_byte_size(), m_data, m_data_lock, m_num_frames, m_ring_capacity, m_slot_frame, offset, ptr, slot_for(), and MayaFlux::Kakshya::variant_bytes().

Referenced by get_frame_typed(), and get_frames_typed_as().

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