1

我正在尝试将 vp8 编码和解码添加到我的流媒体项目中。我正在使用该openni::PIXEL_FORMAT_RGB888格式将来自 OpenNI 的彩色帧读入彩色帧缓冲区​​。然后我尝试使用 vp8 压缩每个 RGB888 帧并通过 UDP 将其流式传输到我的查看器。查看器将帧解压缩为 RGB，然后显示它。我可以使用 JPEG 压缩使端到端功能正常工作，但是当我尝试使用 VP8 编解码器实现压缩时，我得到一个大部分为绿色的框架，顶部有小块白色。

我正在使用 libyuv 将 RGB 与 yv12 进行转换。我的 VP8 编码代码是：

#define VPX_CODEC_DISABLE_COMPAT 1
#include "vpx/vpx_encoder.h"
#include "vpx/vp8cx.h"
#define VPX_INTERFACE (vpx_codec_vp8_cx())

// Code from http://www.webmproject.org/docs/vp8-sdk/example__simple__encoder.html
void vp8::init(const QUALITY quality)
{
    m_quality = vpx_quality_convert(quality);

    // INFO("VPX interface: %s", vpx_codec_iface_name(VPX_INTERFACE));

    const vpx_codec_iface_t* iface = VPX_INTERFACE;
    ASSERT(iface);

    vpx_codec_enc_cfg_t config;
    vpx_codec_err_t res = vpx_codec_enc_config_default(iface, &config, 0);
    ASSERT_THROW(res == VPX_CODEC_OK, "failed to get config: %s", vpx_codec_err_to_string(res));

    // Adjust default target bit-rate to account for actual desktop size.
    config.rc_target_bitrate = width() * height() *
      config.rc_target_bitrate / config.g_w / config.g_h;

    config.g_w = width();
    config.g_h = height();

    m_vpx_codec = new vpx_codec_ctx_t;

    res = vpx_codec_enc_init(m_vpx_codec, iface, &config, 0);
    if (res)
    {
        delete m_vpx_codec;
        m_vpx_codec = nullptr;
        THROW("failed initialize codec: %s", vpx_codec_err_to_string(res)); 
    }
}

vp8::~vp8()
{
    if (m_vpx_codec)
    {   
        vpx_codec_err_t  res = vpx_codec_destroy(m_vpx_codec);
        VPX_CODEC_THROW(m_vpx_codec, res, "error destroying vpx codec");
    }
    delete m_vpx_codec;
}

size_t convert_to_yv12(uint8_t* output, const uint8_t* input)
{
    // YV12 is the same as i420 but with the U and V planes switched
    uint8_t* y_plane = output;
    uint8_t* v_plane = output + num_frame_pixels() * 1;
    uint8_t* u_plane = output + num_frame_pixels() * 5 / 4;

    // Do the conversion here
    switch (input_format())
    {
    case STREAM_FORMAT::COLOR_RGB888:
        // YV12 is the same as i420 except with the u and v planes switched
        libyuv::RAWToI420(input, width() * sizeof(RGB888Pixel),
                          y_plane, width(),
                          u_plane, width() / 2,
                          v_plane, width() / 2,
                          width(), height() );
        break;
    default:
        THROW("can't convert format %1%", input_format());
        break;
    }

    return num_frame_pixels() * 3 / 2;
}

size_t vp8::encode(uint8_t* output, const uint8_t* input, const size_t output_buffer_size, const size_t input_buffer_size)
{
    convert_to_yv12(m_work_buf, input);

    // Encode the frame
    vpx_image_t img_wrapper;
    vpx_img_wrap(&img_wrapper, VPX_IMG_FMT_YV12, width(), height(), 1, m_work_buf);

    vpx_codec_err_t res = vpx_codec_encode(m_vpx_codec, &img_wrapper, m_encoder_count, 1, 
                                           0, VPX_DL_REALTIME); // quality());
    VPX_CODEC_THROW(m_vpx_codec, res, "write_frames: failed to encode frame");

    vpx_codec_iter_t iter = nullptr;
    const vpx_codec_cx_pkt_t *pkt;

    size_t bytes_written = 0;

    while ( (pkt = vpx_codec_get_cx_data(m_vpx_codec, &iter)) )
    {
        switch (pkt->kind)
        {
        case VPX_CODEC_CX_FRAME_PKT:
            ASSERT(bytes_written + pkt->data.frame.sz <= output_buffer_size);

            memcpy(output, pkt->data.frame.buf, pkt->data.frame.sz);

            output += pkt->data.frame.sz;
            bytes_written += pkt->data.frame.sz;
            break;
        default: // ignore everything else
            break;
        }
    }

    ASSERT(vpx_codec_get_cx_data(m_vpx_codec, &iter) == nullptr);

    m_encoder_count++;

    return bytes_written;
}

我的VP8解码代码是：

#define VPX_CODEC_DISABLE_COMPAT 1
#include "vpx/vpx_decoder.h"
#include "vpx/vp8dx.h"
#define VPX_INTERFACE (vpx_codec_vp8_dx())

// Code from http://www.webmproject.org/docs/vp8-sdk/example__simple__decoder.html
vp8::vp8()
{
    // INFO("VPX interface: %s", vpx_codec_iface_name(VPX_INTERFACE));

    m_vpx_codec = new vpx_codec_ctx_t;

    vpx_codec_err_t  res = vpx_codec_dec_init(m_vpx_codec, VPX_INTERFACE, nullptr, 0);
    VPX_CODEC_THROW(m_vpx_codec, res, "failed to initialize the codec");
}

vp8::~vp8()
{
    if (m_vpx_codec)
    {   
        vpx_codec_err_t  res = vpx_codec_destroy(m_vpx_codec);
        VPX_CODEC_THROW(m_vpx_codec, res, "error destroying vpx codec");
    }
    delete m_vpx_codec;
}

void vp8::decode(RGB888Pixel* output, 
                 const uint8_t* input, 
                 const size_t /* output_buffer_size_in_bytes */, 
                 const size_t input_buffer_size_in_bytes)
{
    vpx_codec_err_t res = vpx_codec_decode(m_vpx_codec, input, input_buffer_size_in_bytes, nullptr, 0);
    VPX_CODEC_THROW(m_vpx_codec, res, "error decoding frame");

    // Get a YV12 image frame from the decoder
    vpx_codec_iter_t  iter = NULL;
    vpx_image_t      *img;

    img = vpx_codec_get_frame(m_vpx_codec, &iter);

    ASSERT(vpx_codec_get_frame(m_vpx_codec, &iter) == nullptr);

    ASSERT_EQUAL(img->d_w, width());
    ASSERT_EQUAL(img->d_h, height());

    const uint8_t* y_plane = img->planes[VPX_PLANE_Y];
    const uint8_t* u_plane = img->planes[VPX_PLANE_U];
    const uint8_t* v_plane = img->planes[VPX_PLANE_V];

    int ret =
    libyuv::I420ToRAW(y_plane, img->stride[VPX_PLANE_Y],
                      u_plane, img->stride[VPX_PLANE_U],
                      v_plane, img->stride[VPX_PLANE_V],
                      (uint8*)output, stride_in_bytes(STREAM_FORMAT::COLOR_RGB888, output_stride_in_pixels()),
                      width(), height() );
    ASSERT(ret == 0);

}

基本上，我从 VP8 的简单编码器和解码器示例中复制了所有代码。但我无法弄清楚我的哪个假设是错误的。（另外，我很挣扎，因为没有将 libyuv 与 libvpx 一起使用的示例，这很奇怪，因为两者都是由 Google 开发的）

谢谢！@bensch128

4

0 回答 0