lcldec.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

                    encoded[pixel_ptr+2] = yq -= encoded[pixel_ptr+2];
                    encoded[pixel_ptr+3] = yq -= encoded[pixel_ptr+3];
                    encoded[pixel_ptr+4] = uq -= encoded[pixel_ptr+4];
                    encoded[pixel_ptr+5] = vq -= encoded[pixel_ptr+5];
                    pixel_ptr += 6;
                }
            }
            break;
        case IMGTYPE_YUV211:
            for (row = 0; row < height; row++) {
                pixel_ptr = row * width * 2;
                yq = uq = vq =0;
                for (col = 0; col < width/2; col++) {
                    encoded[pixel_ptr] = yq -= encoded[pixel_ptr];
                    encoded[pixel_ptr+1] = yq -= encoded[pixel_ptr+1];
                    encoded[pixel_ptr+2] = uq -= encoded[pixel_ptr+2];
                    encoded[pixel_ptr+3] = vq -= encoded[pixel_ptr+3];
                    pixel_ptr += 4;
                }
            }
            break;
        case IMGTYPE_YUV420:
            for (row = 0; row < height/2; row++) {
                pixel_ptr = row * width * 3;
                yq = y1q = uq = vq =0;
                for (col = 0; col < width/2; col++) {
                    encoded[pixel_ptr] = yq -= encoded[pixel_ptr];
                    encoded[pixel_ptr+1] = yq -= encoded[pixel_ptr+1];
                    encoded[pixel_ptr+2] = y1q -= encoded[pixel_ptr+2];
                    encoded[pixel_ptr+3] = y1q -= encoded[pixel_ptr+3];
                    encoded[pixel_ptr+4] = uq -= encoded[pixel_ptr+4];
                    encoded[pixel_ptr+5] = vq -= encoded[pixel_ptr+5];
                    pixel_ptr += 6;
                }
            }
            break;
        default:
            av_log(avctx, AV_LOG_ERROR, "BUG! Unknown imagetype in pngfilter switch.\n");
            return -1;
        }
    }

    /* Convert colorspace */
    switch (c->imgtype) {
    case IMGTYPE_YUV111:
        for (row = height - 1; row >= 0; row--) {
            pixel_ptr = row * c->pic.linesize[0];
            for (col = 0; col < width; col++) {
                outptr[pixel_ptr++] = get_b(encoded[0], encoded[1]);
                outptr[pixel_ptr++] = get_g(encoded[0], encoded[1], encoded[2]);
                outptr[pixel_ptr++] = get_r(encoded[0], encoded[2]);
                encoded += 3;
            }
        }
        break;
    case IMGTYPE_YUV422:
        for (row = height - 1; row >= 0; row--) {
            pixel_ptr = row * c->pic.linesize[0];
            for (col = 0; col < width/4; col++) {
                outptr[pixel_ptr++] = get_b(encoded[0], encoded[4]);
                outptr[pixel_ptr++] = get_g(encoded[0], encoded[4], encoded[6]);
                outptr[pixel_ptr++] = get_r(encoded[0], encoded[6]);
                outptr[pixel_ptr++] = get_b(encoded[1], encoded[4]);
                outptr[pixel_ptr++] = get_g(encoded[1], encoded[4], encoded[6]);
                outptr[pixel_ptr++] = get_r(encoded[1], encoded[6]);
                outptr[pixel_ptr++] = get_b(encoded[2], encoded[5]);
                outptr[pixel_ptr++] = get_g(encoded[2], encoded[5], encoded[7]);
                outptr[pixel_ptr++] = get_r(encoded[2], encoded[7]);
                outptr[pixel_ptr++] = get_b(encoded[3], encoded[5]);
                outptr[pixel_ptr++] = get_g(encoded[3], encoded[5], encoded[7]);
                outptr[pixel_ptr++] = get_r(encoded[3], encoded[7]);
                encoded += 8;
            }
        }
        break;
    case IMGTYPE_RGB24:
        for (row = height - 1; row >= 0; row--) {
            pixel_ptr = row * c->pic.linesize[0];
            for (col = 0; col < width; col++) {
                outptr[pixel_ptr++] = encoded[0];
                outptr[pixel_ptr++] = encoded[1];
                outptr[pixel_ptr++] = encoded[2];
                encoded += 3;
            }
        }
        break;
    case IMGTYPE_YUV411:
        for (row = height - 1; row >= 0; row--) {
            pixel_ptr = row * c->pic.linesize[0];
            for (col = 0; col < width/4; col++) {
                outptr[pixel_ptr++] = get_b(encoded[0], encoded[4]);
                outptr[pixel_ptr++] = get_g(encoded[0], encoded[4], encoded[5]);
                outptr[pixel_ptr++] = get_r(encoded[0], encoded[5]);
                outptr[pixel_ptr++] = get_b(encoded[1], encoded[4]);
                outptr[pixel_ptr++] = get_g(encoded[1], encoded[4], encoded[5]);
                outptr[pixel_ptr++] = get_r(encoded[1], encoded[5]);
                outptr[pixel_ptr++] = get_b(encoded[2], encoded[4]);
                outptr[pixel_ptr++] = get_g(encoded[2], encoded[4], encoded[5]);
                outptr[pixel_ptr++] = get_r(encoded[2], encoded[5]);
                outptr[pixel_ptr++] = get_b(encoded[3], encoded[4]);
                outptr[pixel_ptr++] = get_g(encoded[3], encoded[4], encoded[5]);
                outptr[pixel_ptr++] = get_r(encoded[3], encoded[5]);
                encoded += 6;
            }
        }
        break;
    case IMGTYPE_YUV211:
        for (row = height - 1; row >= 0; row--) {
            pixel_ptr = row * c->pic.linesize[0];
            for (col = 0; col < width/2; col++) {
                outptr[pixel_ptr++] = get_b(encoded[0], encoded[2]);
                outptr[pixel_ptr++] = get_g(encoded[0], encoded[2], encoded[3]);
                outptr[pixel_ptr++] = get_r(encoded[0], encoded[3]);
                outptr[pixel_ptr++] = get_b(encoded[1], encoded[2]);
                outptr[pixel_ptr++] = get_g(encoded[1], encoded[2], encoded[3]);
                outptr[pixel_ptr++] = get_r(encoded[1], encoded[3]);
                encoded += 4;
            }
        }
        break;
    case IMGTYPE_YUV420:
        for (row = height / 2 - 1; row >= 0; row--) {
            pixel_ptr = 2 * row * c->pic.linesize[0];
            for (col = 0; col < width/2; col++) {
                outptr[pixel_ptr] = get_b(encoded[0], encoded[4]);
                outptr[pixel_ptr+1] = get_g(encoded[0], encoded[4], encoded[5]);
                outptr[pixel_ptr+2] = get_r(encoded[0], encoded[5]);
                outptr[pixel_ptr+3] = get_b(encoded[1], encoded[4]);
                outptr[pixel_ptr+4] = get_g(encoded[1], encoded[4], encoded[5]);
                outptr[pixel_ptr+5] = get_r(encoded[1], encoded[5]);
                outptr[pixel_ptr-c->pic.linesize[0]] = get_b(encoded[2], encoded[4]);
                outptr[pixel_ptr-c->pic.linesize[0]+1] = get_g(encoded[2], encoded[4], encoded[5]);
                outptr[pixel_ptr-c->pic.linesize[0]+2] = get_r(encoded[2], encoded[5]);
                outptr[pixel_ptr-c->pic.linesize[0]+3] = get_b(encoded[3], encoded[4]);
                outptr[pixel_ptr-c->pic.linesize[0]+4] = get_g(encoded[3], encoded[4], encoded[5]);
                outptr[pixel_ptr-c->pic.linesize[0]+5] = get_r(encoded[3], encoded[5]);
                pixel_ptr += 6;
                encoded += 6;
            }
        }
        break;
    default:
        av_log(avctx, AV_LOG_ERROR, "BUG! Unknown imagetype in image decoder.\n");
        return -1;
    }

    *data_size = sizeof(AVFrame);
    *(AVFrame*)data = c->pic;

    /* always report that the buffer was completely consumed */
    return buf_size;
}

/*
 *
 * Init lcl decoder
 *
 */
static int decode_init(AVCodecContext *avctx)
{
    LclDecContext * const c = avctx->priv_data;
    unsigned int basesize = avctx->width * avctx->height;
    unsigned int max_basesize = ((avctx->width + 3) & ~3) * ((avctx->height + 3) & ~3);
    unsigned int max_decomp_size;
    int zret; // Zlib return code

    c->pic.data[0] = NULL;

#ifdef CONFIG_ZLIB
    // Needed if zlib unused or init aborted before inflateInit
    memset(&(c->zstream), 0, sizeof(z_stream));
#endif

    if (avctx->extradata_size < 8) {
        av_log(avctx, AV_LOG_ERROR, "Extradata size too small.\n");
        return 1;
    }

    if (avcodec_check_dimensions(avctx, avctx->width, avctx->height) < 0) {
        return 1;
    }

    /* Check codec type */
    if (((avctx->codec_id == CODEC_ID_MSZH)  && (*((char *)avctx->extradata + 7) != CODEC_MSZH)) ||
        ((avctx->codec_id == CODEC_ID_ZLIB)  && (*((char *)avctx->extradata + 7) != CODEC_ZLIB))) {
        av_log(avctx, AV_LOG_ERROR, "Codec id and codec type mismatch. This should not happen.\n");
    }

    /* Detect image type */
    switch (c->imgtype = *((char *)avctx->extradata + 4)) {
    case IMGTYPE_YUV111:
        c->decomp_size = basesize * 3;
        max_decomp_size = max_basesize * 3;
        av_log(avctx, AV_LOG_INFO, "Image type is YUV 1:1:1.\n");
        break;
    case IMGTYPE_YUV422:
        c->decomp_size = basesize * 2;
        max_decomp_size = max_basesize * 2;
        av_log(avctx, AV_LOG_INFO, "Image type is YUV 4:2:2.\n");
        break;
    case IMGTYPE_RGB24:
        c->decomp_size = basesize * 3;
        max_decomp_size = max_basesize * 3;
        av_log(avctx, AV_LOG_INFO, "Image type is RGB 24.\n");
        break;
    case IMGTYPE_YUV411:
        c->decomp_size = basesize / 2 * 3;
        max_decomp_size = max_basesize / 2 * 3;
        av_log(avctx, AV_LOG_INFO, "Image type is YUV 4:1:1.\n");
        break;
    case IMGTYPE_YUV211:
        c->decomp_size = basesize * 2;
        max_decomp_size = max_basesize * 2;
        av_log(avctx, AV_LOG_INFO, "Image type is YUV 2:1:1.\n");
        break;
    case IMGTYPE_YUV420:
        c->decomp_size = basesize / 2 * 3;
        max_decomp_size = max_basesize / 2 * 3;
        av_log(avctx, AV_LOG_INFO, "Image type is YUV 4:2:0.\n");
        break;
    default:
        av_log(avctx, AV_LOG_ERROR, "Unsupported image format %d.\n", c->imgtype);
        return 1;
    }

    /* Detect compression method */
    c->compression = *((char *)avctx->extradata + 5);
    switch (avctx->codec_id) {
    case CODEC_ID_MSZH:
        switch (c->compression) {
        case COMP_MSZH:
            av_log(avctx, AV_LOG_INFO, "Compression enabled.\n");
            break;
        case COMP_MSZH_NOCOMP:
            c->decomp_size = 0;
            av_log(avctx, AV_LOG_INFO, "No compression.\n");
            break;
        default:
            av_log(avctx, AV_LOG_ERROR, "Unsupported compression format for MSZH (%d).\n", c->compression);
            return 1;
        }
        break;
    case CODEC_ID_ZLIB:
#ifdef CONFIG_ZLIB
        switch (c->compression) {
        case COMP_ZLIB_HISPEED:
            av_log(avctx, AV_LOG_INFO, "High speed compression.\n");
            break;
        case COMP_ZLIB_HICOMP:
            av_log(avctx, AV_LOG_INFO, "High compression.\n");
            break;
        case COMP_ZLIB_NORMAL:
            av_log(avctx, AV_LOG_INFO, "Normal compression.\n");
            break;
        default:
            if ((c->compression < Z_NO_COMPRESSION) || (c->compression > Z_BEST_COMPRESSION)) {
                av_log(avctx, AV_LOG_ERROR, "Unsupported compression level for ZLIB: (%d).\n", c->compression);
                return 1;
            }
            av_log(avctx, AV_LOG_INFO, "Compression level for ZLIB: (%d).\n", c->compression);
        }
#else
        av_log(avctx, AV_LOG_ERROR, "Zlib support not compiled.\n");
        return 1;
#endif
        break;
    default:
        av_log(avctx, AV_LOG_ERROR, "BUG! Unknown codec in compression switch.\n");
        return 1;
    }

    /* Allocate decompression buffer */
    if (c->decomp_size) {
        if ((c->decomp_buf = av_malloc(max_decomp_size)) == NULL) {
            av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n");
            return 1;
        }
    }

    /* Detect flags */
    c->flags = *((char *)avctx->extradata + 6);
    if (c->flags & FLAG_MULTITHREAD)
        av_log(avctx, AV_LOG_INFO, "Multithread encoder flag set.\n");
    if (c->flags & FLAG_NULLFRAME)
        av_log(avctx, AV_LOG_INFO, "Nullframe insertion flag set.\n");
    if ((avctx->codec_id == CODEC_ID_ZLIB) && (c->flags & FLAG_PNGFILTER))
        av_log(avctx, AV_LOG_INFO, "PNG filter flag set.\n");
    if (c->flags & FLAGMASK_UNUSED)
        av_log(avctx, AV_LOG_ERROR, "Unknown flag set (%d).\n", c->flags);

    /* If needed init zlib */
    if (avctx->codec_id == CODEC_ID_ZLIB) {
#ifdef CONFIG_ZLIB
        c->zstream.zalloc = Z_NULL;
        c->zstream.zfree = Z_NULL;
        c->zstream.opaque = Z_NULL;
        zret = inflateInit(&(c->zstream));
        if (zret != Z_OK) {
            av_log(avctx, AV_LOG_ERROR, "Inflate init error: %d\n", zret);
            return 1;
        }
#else
        av_log(avctx, AV_LOG_ERROR, "Zlib support not compiled.\n");
        return 1;
#endif
    }

    avctx->pix_fmt = PIX_FMT_BGR24;

    return 0;
}

/*
 *
 * Uninit lcl decoder
 *
 */
static int decode_end(AVCodecContext *avctx)
{
    LclDecContext * const c = avctx->priv_data;

    if (c->pic.data[0])
        avctx->release_buffer(avctx, &c->pic);
#ifdef CONFIG_ZLIB
    inflateEnd(&(c->zstream));
#endif

    return 0;
}

#ifdef CONFIG_MSZH_DECODER
AVCodec mszh_decoder = {
    "mszh",
    CODEC_TYPE_VIDEO,
    CODEC_ID_MSZH,
    sizeof(LclDecContext),
    decode_init,
    NULL,
    decode_end,
    decode_frame,
    CODEC_CAP_DR1,
};
#endif

#ifdef CONFIG_ZLIB_DECODER
AVCodec zlib_decoder = {
    "zlib",
    CODEC_TYPE_VIDEO,
    CODEC_ID_ZLIB,
    sizeof(LclDecContext),
    decode_init,
    NULL,
    decode_end,
    decode_frame,
    CODEC_CAP_DR1,
};
#endif