imgconvert.c

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

        picture->linesize[3] = width;
        return 2 * size + 2 * size2;
    case PIX_FMT_NV12:
    case PIX_FMT_NV21:
        w2 = (width + (1 << pinfo->x_chroma_shift) - 1) >> pinfo->x_chroma_shift;
        h2 = (height + (1 << pinfo->y_chroma_shift) - 1) >> pinfo->y_chroma_shift;
        size2 = w2 * h2 * 2;
        picture->data[0] = ptr;
        picture->data[1] = picture->data[0] + size;
        picture->data[2] = NULL;
        picture->data[3] = NULL;
        picture->linesize[0] = width;
        picture->linesize[1] = w2;
        picture->linesize[2] = 0;
        picture->linesize[3] = 0;
        return size + 2 * size2;
    case PIX_FMT_RGB24:
    case PIX_FMT_BGR24:
        picture->data[0] = ptr;
        picture->data[1] = NULL;
        picture->data[2] = NULL;
        picture->data[3] = NULL;
        picture->linesize[0] = width * 3;
        return size * 3;
    case PIX_FMT_RGB32:
    case PIX_FMT_BGR32:
    case PIX_FMT_RGB32_1:
    case PIX_FMT_BGR32_1:
        picture->data[0] = ptr;
        picture->data[1] = NULL;
        picture->data[2] = NULL;
        picture->data[3] = NULL;
        picture->linesize[0] = width * 4;
        return size * 4;
    case PIX_FMT_GRAY16BE:
    case PIX_FMT_GRAY16LE:
    case PIX_FMT_BGR555:
    case PIX_FMT_BGR565:
    case PIX_FMT_RGB555:
    case PIX_FMT_RGB565:
    case PIX_FMT_YUYV422:
        picture->data[0] = ptr;
        picture->data[1] = NULL;
        picture->data[2] = NULL;
        picture->data[3] = NULL;
        picture->linesize[0] = width * 2;
        return size * 2;
    case PIX_FMT_UYVY422:
        picture->data[0] = ptr;
        picture->data[1] = NULL;
        picture->data[2] = NULL;
        picture->data[3] = NULL;
        picture->linesize[0] = width * 2;
        return size * 2;
    case PIX_FMT_UYYVYY411:
        picture->data[0] = ptr;
        picture->data[1] = NULL;
        picture->data[2] = NULL;
        picture->data[3] = NULL;
        picture->linesize[0] = width + width/2;
        return size + size/2;
    case PIX_FMT_RGB8:
    case PIX_FMT_BGR8:
    case PIX_FMT_RGB4_BYTE:
    case PIX_FMT_BGR4_BYTE:
    case PIX_FMT_GRAY8:
        picture->data[0] = ptr;
        picture->data[1] = NULL;
        picture->data[2] = NULL;
        picture->data[3] = NULL;
        picture->linesize[0] = width;
        return size;
    case PIX_FMT_RGB4:
    case PIX_FMT_BGR4:
        picture->data[0] = ptr;
        picture->data[1] = NULL;
        picture->data[2] = NULL;
        picture->data[3] = NULL;
        picture->linesize[0] = width / 2;
        return size / 2;
    case PIX_FMT_MONOWHITE:
    case PIX_FMT_MONOBLACK:
        picture->data[0] = ptr;
        picture->data[1] = NULL;
        picture->data[2] = NULL;
        picture->data[3] = NULL;
        picture->linesize[0] = (width + 7) >> 3;
        return picture->linesize[0] * height;
    case PIX_FMT_PAL8:
        size2 = (size + 3) & ~3;
        picture->data[0] = ptr;
        picture->data[1] = ptr + size2; /* palette is stored here as 256 32 bit words */
        picture->data[2] = NULL;
        picture->data[3] = NULL;
        picture->linesize[0] = width;
        picture->linesize[1] = 4;
        return size2 + 256 * 4;
    default:
fail:
        picture->data[0] = NULL;
        picture->data[1] = NULL;
        picture->data[2] = NULL;
        picture->data[3] = NULL;
        return -1;
    }
}

int avpicture_layout(const AVPicture* src, int pix_fmt, int width, int height,
                     unsigned char *dest, int dest_size)
{
    const PixFmtInfo* pf = &pix_fmt_info[pix_fmt];
    int i, j, w, h, data_planes;
    const unsigned char* s;
    int size = avpicture_get_size(pix_fmt, width, height);

    if (size > dest_size || size < 0)
        return -1;

    if (pf->pixel_type == FF_PIXEL_PACKED || pf->pixel_type == FF_PIXEL_PALETTE) {
        if (pix_fmt == PIX_FMT_YUYV422 ||
            pix_fmt == PIX_FMT_UYVY422 ||
            pix_fmt == PIX_FMT_BGR565 ||
            pix_fmt == PIX_FMT_BGR555 ||
            pix_fmt == PIX_FMT_RGB565 ||
            pix_fmt == PIX_FMT_RGB555)
            w = width * 2;
        else if (pix_fmt == PIX_FMT_UYYVYY411)
          w = width + width/2;
        else if (pix_fmt == PIX_FMT_PAL8)
          w = width;
        else
          w = width * (pf->depth * pf->nb_channels / 8);

        data_planes = 1;
        h = height;
    } else {
        data_planes = pf->nb_channels;
        w = (width*pf->depth + 7)/8;
        h = height;
    }

    for (i=0; i<data_planes; i++) {
         if (i == 1) {
             w = width >> pf->x_chroma_shift;
             h = height >> pf->y_chroma_shift;
         }
         s = src->data[i];
         for(j=0; j<h; j++) {
             memcpy(dest, s, w);
             dest += w;
             s += src->linesize[i];
         }
    }

    if (pf->pixel_type == FF_PIXEL_PALETTE)
        memcpy((unsigned char *)(((size_t)dest + 3) & ~3), src->data[1], 256 * 4);

    return size;
}

int avpicture_get_size(int pix_fmt, int width, int height)
{
    AVPicture dummy_pict;
    return avpicture_fill(&dummy_pict, NULL, pix_fmt, width, height);
}

int avcodec_get_pix_fmt_loss(int dst_pix_fmt, int src_pix_fmt,
                             int has_alpha)
{
    const PixFmtInfo *pf, *ps;
    int loss;

    ps = &pix_fmt_info[src_pix_fmt];
    pf = &pix_fmt_info[dst_pix_fmt];

    /* compute loss */
    loss = 0;
    pf = &pix_fmt_info[dst_pix_fmt];
    if (pf->depth < ps->depth ||
        (dst_pix_fmt == PIX_FMT_RGB555 && src_pix_fmt == PIX_FMT_RGB565))
        loss |= FF_LOSS_DEPTH;
    if (pf->x_chroma_shift > ps->x_chroma_shift ||
        pf->y_chroma_shift > ps->y_chroma_shift)
        loss |= FF_LOSS_RESOLUTION;
    switch(pf->color_type) {
    case FF_COLOR_RGB:
        if (ps->color_type != FF_COLOR_RGB &&
            ps->color_type != FF_COLOR_GRAY)
            loss |= FF_LOSS_COLORSPACE;
        break;
    case FF_COLOR_GRAY:
        if (ps->color_type != FF_COLOR_GRAY)
            loss |= FF_LOSS_COLORSPACE;
        break;
    case FF_COLOR_YUV:
        if (ps->color_type != FF_COLOR_YUV)
            loss |= FF_LOSS_COLORSPACE;
        break;
    case FF_COLOR_YUV_JPEG:
        if (ps->color_type != FF_COLOR_YUV_JPEG &&
            ps->color_type != FF_COLOR_YUV &&
            ps->color_type != FF_COLOR_GRAY)
            loss |= FF_LOSS_COLORSPACE;
        break;
    default:
        /* fail safe test */
        if (ps->color_type != pf->color_type)
            loss |= FF_LOSS_COLORSPACE;
        break;
    }
    if (pf->color_type == FF_COLOR_GRAY &&
        ps->color_type != FF_COLOR_GRAY)
        loss |= FF_LOSS_CHROMA;
    if (!pf->is_alpha && (ps->is_alpha && has_alpha))
        loss |= FF_LOSS_ALPHA;
    if (pf->pixel_type == FF_PIXEL_PALETTE &&
        (ps->pixel_type != FF_PIXEL_PALETTE && ps->color_type != FF_COLOR_GRAY))
        loss |= FF_LOSS_COLORQUANT;
    return loss;
}

static int avg_bits_per_pixel(int pix_fmt)
{
    int bits;
    const PixFmtInfo *pf;

    pf = &pix_fmt_info[pix_fmt];
    switch(pf->pixel_type) {
    case FF_PIXEL_PACKED:
        switch(pix_fmt) {
        case PIX_FMT_YUYV422:
        case PIX_FMT_UYVY422:
        case PIX_FMT_RGB565:
        case PIX_FMT_RGB555:
        case PIX_FMT_BGR565:
        case PIX_FMT_BGR555:
            bits = 16;
            break;
        case PIX_FMT_UYYVYY411:
            bits = 12;
            break;
        default:
            bits = pf->depth * pf->nb_channels;
            break;
        }
        break;
    case FF_PIXEL_PLANAR:
        if (pf->x_chroma_shift == 0 && pf->y_chroma_shift == 0) {
            bits = pf->depth * pf->nb_channels;
        } else {
            bits = pf->depth + ((2 * pf->depth) >>
                                (pf->x_chroma_shift + pf->y_chroma_shift));
        }
        break;
    case FF_PIXEL_PALETTE:
        bits = 8;
        break;
    default:
        bits = -1;
        break;
    }
    return bits;
}

static int avcodec_find_best_pix_fmt1(int pix_fmt_mask,
                                      int src_pix_fmt,
                                      int has_alpha,
                                      int loss_mask)
{
    int dist, i, loss, min_dist, dst_pix_fmt;

    /* find exact color match with smallest size */
    dst_pix_fmt = -1;
    min_dist = 0x7fffffff;
    for(i = 0;i < PIX_FMT_NB; i++) {
        if (pix_fmt_mask & (1 << i)) {
            loss = avcodec_get_pix_fmt_loss(i, src_pix_fmt, has_alpha) & loss_mask;
            if (loss == 0) {
                dist = avg_bits_per_pixel(i);
                if (dist < min_dist) {
                    min_dist = dist;
                    dst_pix_fmt = i;
                }
            }
        }
    }
    return dst_pix_fmt;
}

int avcodec_find_best_pix_fmt(int pix_fmt_mask, int src_pix_fmt,
                              int has_alpha, int *loss_ptr)
{
    int dst_pix_fmt, loss_mask, i;
    static const int loss_mask_order[] = {
        ~0, /* no loss first */
        ~FF_LOSS_ALPHA,
        ~FF_LOSS_RESOLUTION,
        ~(FF_LOSS_COLORSPACE | FF_LOSS_RESOLUTION),
        ~FF_LOSS_COLORQUANT,
        ~FF_LOSS_DEPTH,
        0,
    };

    /* try with successive loss */
    i = 0;
    for(;;) {
        loss_mask = loss_mask_order[i++];
        dst_pix_fmt = avcodec_find_best_pix_fmt1(pix_fmt_mask, src_pix_fmt,
                                                 has_alpha, loss_mask);
        if (dst_pix_fmt >= 0)
            goto found;
        if (loss_mask == 0)
            break;
    }
    return -1;
 found:
    if (loss_ptr)
        *loss_ptr = avcodec_get_pix_fmt_loss(dst_pix_fmt, src_pix_fmt, has_alpha);
    return dst_pix_fmt;
}

void ff_img_copy_plane(uint8_t *dst, int dst_wrap,
                           const uint8_t *src, int src_wrap,
                           int width, int height)
{
    if((!dst) || (!src))
        return;
    for(;height > 0; height--) {
        memcpy(dst, src, width);
        dst += dst_wrap;
        src += src_wrap;
    }
}

void av_picture_copy(AVPicture *dst, const AVPicture *src,
              int pix_fmt, int width, int height)
{
    int bwidth, bits, i;
    const PixFmtInfo *pf = &pix_fmt_info[pix_fmt];

    pf = &pix_fmt_info[pix_fmt];
    switch(pf->pixel_type) {
    case FF_PIXEL_PACKED:
        switch(pix_fmt) {
        case PIX_FMT_YUYV422:
        case PIX_FMT_UYVY422:
        case PIX_FMT_RGB565:
        case PIX_FMT_RGB555:
        case PIX_FMT_BGR565:
        case PIX_FMT_BGR555:
            bits = 16;
            break;
        case PIX_FMT_UYYVYY411:
            bits = 12;
            break;
        default:
            bits = pf->depth * pf->nb_channels;
            break;
        }
        bwidth = (width * bits + 7) >> 3;
        ff_img_copy_plane(dst->data[0], dst->linesize[0],
                       src->data[0], src->linesize[0],
                       bwidth, height);
        break;
    case FF_PIXEL_PLANAR:
        for(i = 0; i < pf->nb_channels; i++) {
            int w, h;
            w = width;
            h = height;
            if (i == 1 || i == 2) {
                w >>= pf->x_chroma_shift;
                h >>= pf->y_chroma_shift;
            }
            bwidth = (w * pf->depth + 7) >> 3;
            ff_img_copy_plane(dst->data[i], dst->linesize[i],
                           src->data[i], src->linesize[i],
                           bwidth, h);
        }
        break;
    case FF_PIXEL_PALETTE:
        ff_img_copy_plane(dst->data[0], dst->linesize[0],
                       src->data[0], src->linesize[0],
                       width, height);
        /* copy the palette */
        ff_img_copy_plane(dst->data[1], dst->linesize[1],
                       src->data[1], src->linesize[1],
                       4, 256);
        break;
    }
}

/* XXX: totally non optimized */

static void yuyv422_to_yuv420p(AVPicture *dst, const AVPicture *src,
                              int width, int height)
{
    const uint8_t *p, *p1;
    uint8_t *lum, *cr, *cb, *lum1, *cr1, *cb1;
    int w;

    p1 = src->data[0];
    lum1 = dst->data[0];
    cb1 = dst->data[1];
    cr1 = dst->data[2];

    for(;height >= 1; height -= 2) {
        p = p1;
        lum = lum1;
        cb = cb1;
        cr = cr1;
        for(w = width; w >= 2; w -= 2) {
            lum[0] = p[0];
            cb[0] = p[1];
            lum[1] = p[2];
            cr[0] = p[3];
            p += 4;
            lum += 2;
            cb++;
            cr++;
        }
        if (w) {
            lum[0] = p[0];
            cb[0] = p[1];
            cr[0] = p[3];
            cb++;
            cr++;
        }
        p1 += src->linesize[0];
        lum1 += dst->linesize[0];
        if (height>1) {
            p = p1;
            lum = lum1;
            for(w = width; w >= 2; w -= 2) {
                lum[0] = p[0];
                lum[1] = p[2];
                p += 4;
                lum += 2;
            }
            if (w) {
                lum[0] = p[0];
            }
            p1 += src->linesize[0];
            lum1 += dst->linesize[0];
        }
        cb1 += dst->linesize[1];
        cr1 += dst->linesize[2];
    }
}

static void uyvy422_to_yuv420p(AVPicture *dst, const AVPicture *src,
                              int width, int height)
{
    const uint8_t *p, *p1;
    uint8_t *lum, *cr, *cb, *lum1, *cr1, *cb1;
    int w;

    p1 = src->data[0];

    lum1 = dst->data[0];
    cb1 = dst->data[1];
    cr1 = dst->data[2];

    for(;height >= 1; height -= 2) {
        p = p1;
        lum = lum1;
        cb = cb1;
        cr = cr1;
        for(w = width; w >= 2; w -= 2) {
            lum[0] = p[1];
            cb[0] = p[0];
            lum[1] = p[3];
            cr[0] = p[2];
            p += 4;