png.c

从FFMPEG转换而来的H264解码程序,VC下编译..

    int ret, crc;

    s->bytestream_start=
    s->bytestream= buf;
    s->bytestream_end= buf + buf_size;

    /* check signature */
    if (memcmp(s->bytestream, pngsig, 8) != 0)
        return -1;
    s->bytestream+= 8;
    s->y=
    s->state=0;
//    memset(s, 0, sizeof(PNGContext));
    /* init the zlib */
    s->zstream.zalloc = png_zalloc;
    s->zstream.zfree = png_zfree;
    s->zstream.opaque = NULL;
    ret = inflateInit(&s->zstream);
    if (ret != Z_OK)
        return -1;
    for(;;) {
        int tag32;
        if (s->bytestream >= s->bytestream_end)
            goto fail;
        length = bytestream_get_be32(&s->bytestream);
        if (length > 0x7fffffff)
            goto fail;
        tag32 = bytestream_get_be32(&s->bytestream);
        tag = bswap_32(tag32);
        switch(tag) {
        case MKTAG('I', 'H', 'D', 'R'):
            if (length != 13)
                goto fail;
            s->width = bytestream_get_be32(&s->bytestream);
            s->height = bytestream_get_be32(&s->bytestream);
            if(avcodec_check_dimensions(avctx, s->width, s->height)){
                s->width= s->height= 0;
                goto fail;
            }
            s->bit_depth = *s->bytestream++;
            s->color_type = *s->bytestream++;
            s->compression_type = *s->bytestream++;
            s->filter_type = *s->bytestream++;
            s->interlace_type = *s->bytestream++;
            crc = bytestream_get_be32(&s->bytestream);
            s->state |= PNG_IHDR;
            break;
        case MKTAG('I', 'D', 'A', 'T'):
            if (!(s->state & PNG_IHDR))
                goto fail;
            if (!(s->state & PNG_IDAT)) {
                /* init image info */
                avctx->width = s->width;
                avctx->height = s->height;

                s->channels = png_get_nb_channels(s->color_type);
                s->bits_per_pixel = s->bit_depth * s->channels;
                s->bpp = (s->bits_per_pixel + 7) >> 3;
                s->row_size = (avctx->width * s->bits_per_pixel + 7) >> 3;

                if (s->bit_depth == 8 &&
                    s->color_type == PNG_COLOR_TYPE_RGB) {
                    avctx->pix_fmt = PIX_FMT_RGB24;
                } else if (s->bit_depth == 8 &&
                           s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
                    avctx->pix_fmt = PIX_FMT_RGB32;
                } else if (s->bit_depth == 8 &&
                           s->color_type == PNG_COLOR_TYPE_GRAY) {
                    avctx->pix_fmt = PIX_FMT_GRAY8;
                } else if (s->bit_depth == 16 &&
                           s->color_type == PNG_COLOR_TYPE_GRAY) {
                    avctx->pix_fmt = PIX_FMT_GRAY16BE;
                } else if (s->bit_depth == 1 &&
                           s->color_type == PNG_COLOR_TYPE_GRAY) {
                    avctx->pix_fmt = PIX_FMT_MONOBLACK;
                } else if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
                    avctx->pix_fmt = PIX_FMT_PAL8;
                } else {
                    goto fail;
                }
                if(picture->data[0]==NULL){
                    if(p->data[0])
                        avctx->release_buffer(avctx, p);

                    p->reference= 0;
                    if(avctx->get_buffer(avctx, p) < 0){
                        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
                        goto fail;
                    }
                }else{
                    p->data[0]=picture->data[0];
                    p->linesize[0]=picture->linesize[0];
                    if (p->linesize[0]<0)
                        p->data[0]+=(avctx->height-1)*(-p->linesize[0]);
                }

                p->pict_type= FF_I_TYPE;
                p->key_frame= 1;
                p->interlaced_frame = !!s->interlace_type;

                /* compute the compressed row size */
                if (!s->interlace_type) {
                    s->crow_size = s->row_size + 1;
                } else {
                    s->pass = 0;
                    s->pass_row_size = png_pass_row_size(s->pass,
                                                         s->bits_per_pixel,
                                                         s->width);
                    s->crow_size = s->pass_row_size + 1;
                }
                s->image_buf = p->data[0];
                s->image_linesize = p->linesize[0];
                /* copy the palette if needed */
                if (s->color_type == PNG_COLOR_TYPE_PALETTE)
                    memcpy(avctx->palctrl->palette, s->palette, 256 * sizeof(uint32_t));
                /* empty row is used if differencing to the first row */
                s->last_row = av_mallocz(s->row_size);
                if (!s->last_row)
                    goto fail;
                if (s->interlace_type ||
                    s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
                    s->tmp_row = av_malloc(s->row_size);
                    if (!s->tmp_row)
                        goto fail;
                }
                /* compressed row */
                s->crow_buf = av_malloc(s->row_size + 1);
                if (!s->crow_buf)
                    goto fail;
                s->zstream.avail_out = s->crow_size;
                s->zstream.next_out = s->crow_buf;
            }
            s->state |= PNG_IDAT;
            if (png_decode_idat(s, length) < 0)
                goto fail;
            /* skip crc */
            crc = bytestream_get_be32(&s->bytestream);
            break;
        case MKTAG('P', 'L', 'T', 'E'):
            {
                int n, i, r, g, b;

                if ((length % 3) != 0 || length > 256 * 3)
                    goto skip_tag;
                /* read the palette */
                n = length / 3;
                for(i=0;i<n;i++) {
                    r = *s->bytestream++;
                    g = *s->bytestream++;
                    b = *s->bytestream++;
                    s->palette[i] = (0xff << 24) | (r << 16) | (g << 8) | b;
                }
                for(;i<256;i++) {
                    s->palette[i] = (0xff << 24);
                }
                s->state |= PNG_PLTE;
                crc = bytestream_get_be32(&s->bytestream);
            }
            break;
        case MKTAG('t', 'R', 'N', 'S'):
            {
                int v, i;

                /* read the transparency. XXX: Only palette mode supported */
                if (s->color_type != PNG_COLOR_TYPE_PALETTE ||
                    length > 256 ||
                    !(s->state & PNG_PLTE))
                    goto skip_tag;
                for(i=0;i<length;i++) {
                    v = *s->bytestream++;
                    s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
                }
                crc = bytestream_get_be32(&s->bytestream);
            }
            break;
        case MKTAG('I', 'E', 'N', 'D'):
            if (!(s->state & PNG_ALLIMAGE))
                goto fail;
            crc = bytestream_get_be32(&s->bytestream);
            goto exit_loop;
        default:
            /* skip tag */
        skip_tag:
            s->bytestream += length + 4;
            break;
        }
    }
 exit_loop:
    *picture= *(AVFrame*)&s->picture;
    *data_size = sizeof(AVPicture);

    ret = s->bytestream - s->bytestream_start;
 the_end:
    inflateEnd(&s->zstream);
    av_freep(&s->crow_buf);
    av_freep(&s->last_row);
    av_freep(&s->tmp_row);
    return ret;
 fail:
    ret = -1;
    goto the_end;
}

#ifdef CONFIG_ENCODERS
static void png_write_chunk(uint8_t **f, uint32_t tag,
                            const uint8_t *buf, int length)
{
    uint32_t crc;
    uint8_t tagbuf[4];

    bytestream_put_be32(f, length);
    crc = crc32(0, Z_NULL, 0);
    AV_WL32(tagbuf, tag);
    crc = crc32(crc, tagbuf, 4);
    bytestream_put_be32(f, bswap_32(tag));
    if (length > 0) {
        crc = crc32(crc, buf, length);
        memcpy(*f, buf, length);
        *f += length;
    }
    bytestream_put_be32(f, crc);
}

/* XXX: do filtering */
static int png_write_row(PNGContext *s, const uint8_t *data, int size)
{
    int ret;

    s->zstream.avail_in = size;
    s->zstream.next_in = (uint8_t *)data;
    while (s->zstream.avail_in > 0) {
        ret = deflate(&s->zstream, Z_NO_FLUSH);
        if (ret != Z_OK)
            return -1;
        if (s->zstream.avail_out == 0) {
            if(s->bytestream_end - s->bytestream > IOBUF_SIZE + 100)
                png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, IOBUF_SIZE);
            s->zstream.avail_out = IOBUF_SIZE;
            s->zstream.next_out = s->buf;
        }
    }
    return 0;
}
#endif /* CONFIG_ENCODERS */

static int common_init(AVCodecContext *avctx){
    PNGContext *s = avctx->priv_data;

    avcodec_get_frame_defaults((AVFrame*)&s->picture);
    avctx->coded_frame= (AVFrame*)&s->picture;
//    s->avctx= avctx;

    return 0;
}

#ifdef CONFIG_ENCODERS
static int encode_frame(AVCodecContext *avctx, unsigned char *buf, int buf_size, void *data){
    PNGContext *s = avctx->priv_data;
    AVFrame *pict = data;
    AVFrame * const p= (AVFrame*)&s->picture;
    int bit_depth, color_type, y, len, row_size, ret, is_progressive;
    int bits_per_pixel, pass_row_size;
    uint8_t *ptr;
    uint8_t *crow_buf = NULL;
    uint8_t *tmp_buf = NULL;

    *p = *pict;
    p->pict_type= FF_I_TYPE;
    p->key_frame= 1;

    s->bytestream_start=
    s->bytestream= buf;
    s->bytestream_end= buf+buf_size;

    is_progressive = !!(avctx->flags & CODEC_FLAG_INTERLACED_DCT);
    switch(avctx->pix_fmt) {
    case PIX_FMT_RGB32:
        bit_depth = 8;
        color_type = PNG_COLOR_TYPE_RGB_ALPHA;
        break;
    case PIX_FMT_RGB24:
    case PIX_FMT_BGR24:
        bit_depth = 8;
        color_type = PNG_COLOR_TYPE_RGB;
        break;
    case PIX_FMT_GRAY8:
        bit_depth = 8;
        color_type = PNG_COLOR_TYPE_GRAY;
        break;
    case PIX_FMT_MONOBLACK:
        bit_depth = 1;
        color_type = PNG_COLOR_TYPE_GRAY;
        break;
    case PIX_FMT_PAL8:
        bit_depth = 8;
        color_type = PNG_COLOR_TYPE_PALETTE;
        break;
    default:
        return -1;
    }
    bits_per_pixel = png_get_nb_channels(color_type) * bit_depth;
    row_size = (avctx->width * bits_per_pixel + 7) >> 3;

    s->zstream.zalloc = png_zalloc;
    s->zstream.zfree = png_zfree;
    s->zstream.opaque = NULL;
    ret = deflateInit2(&s->zstream,p->quality,
                       Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY);
    if (ret != Z_OK)
        return -1;
    crow_buf = av_malloc(row_size + 1);
    if (!crow_buf)
        goto fail;
    if (is_progressive) {
        tmp_buf = av_malloc(row_size + 1);
        if (!tmp_buf)
            goto fail;
    }

    /* write png header */
    memcpy(s->bytestream, pngsig, 8);
    s->bytestream += 8;

    AV_WB32(s->buf, avctx->width);
    AV_WB32(s->buf + 4, avctx->height);
    s->buf[8] = bit_depth;
    s->buf[9] = color_type;
    s->buf[10] = 0; /* compression type */
    s->buf[11] = 0; /* filter type */
    s->buf[12] = is_progressive; /* interlace type */

    png_write_chunk(&s->bytestream, MKTAG('I', 'H', 'D', 'R'), s->buf, 13);

    /* put the palette if needed */
    if (color_type == PNG_COLOR_TYPE_PALETTE) {
        int has_alpha, alpha, i;
        unsigned int v;
        uint32_t *palette;
        uint8_t *alpha_ptr;

        palette = (uint32_t *)p->data[1];
        ptr = s->buf;
        alpha_ptr = s->buf + 256 * 3;
        has_alpha = 0;
        for(i = 0; i < 256; i++) {
            v = palette[i];
            alpha = v >> 24;
            if (alpha && alpha != 0xff)
                has_alpha = 1;
            *alpha_ptr++ = alpha;
            bytestream_put_be24(&ptr, v);
        }
        png_write_chunk(&s->bytestream, MKTAG('P', 'L', 'T', 'E'), s->buf, 256 * 3);
        if (has_alpha) {
            png_write_chunk(&s->bytestream, MKTAG('t', 'R', 'N', 'S'), s->buf + 256 * 3, 256);
        }
    }

    /* now put each row */
    s->zstream.avail_out = IOBUF_SIZE;
    s->zstream.next_out = s->buf;
    if (is_progressive) {
        uint8_t *ptr1;
        int pass;

        for(pass = 0; pass < NB_PASSES; pass++) {
            /* NOTE: a pass is completely omited if no pixels would be
               output */
            pass_row_size = png_pass_row_size(pass, bits_per_pixel, avctx->width);
            if (pass_row_size > 0) {
                for(y = 0; y < avctx->height; y++) {
                    if ((png_pass_ymask[pass] << (y & 7)) & 0x80) {
                        ptr = p->data[0] + y * p->linesize[0];
                        if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
                            convert_from_rgb32(tmp_buf, ptr, avctx->width);
                            ptr1 = tmp_buf;
                        } else {
                            ptr1 = ptr;
                        }
                        png_get_interlaced_row(crow_buf + 1, pass_row_size,
                                               bits_per_pixel, pass,
                                               ptr1, avctx->width);
                        crow_buf[0] = PNG_FILTER_VALUE_NONE;
                        png_write_row(s, crow_buf, pass_row_size + 1);
                    }
                }
            }
        }
    } else {
        for(y = 0; y < avctx->height; y++) {
            ptr = p->data[0] + y * p->linesize[0];
            if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
                convert_from_rgb32(crow_buf + 1, ptr, avctx->width);
            else
                memcpy(crow_buf + 1, ptr, row_size);
            crow_buf[0] = PNG_FILTER_VALUE_NONE;
            png_write_row(s, crow_buf, row_size + 1);
        }
    }
    /* compress last bytes */
    for(;;) {
        ret = deflate(&s->zstream, Z_FINISH);
        if (ret == Z_OK || ret == Z_STREAM_END) {
            len = IOBUF_SIZE - s->zstream.avail_out;
            if (len > 0 && s->bytestream_end - s->bytestream > len + 100) {
                png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, len);
            }
            s->zstream.avail_out = IOBUF_SIZE;
            s->zstream.next_out = s->buf;
            if (ret == Z_STREAM_END)
                break;
        } else {
            goto fail;
        }
    }
    png_write_chunk(&s->bytestream, MKTAG('I', 'E', 'N', 'D'), NULL, 0);

    ret = s->bytestream - s->bytestream_start;
 the_end:
    av_free(crow_buf);
    av_free(tmp_buf);
    deflateEnd(&s->zstream);
    return ret;
 fail:
    ret = -1;
    goto the_end;
}
#endif

AVCodec png_decoder = {
    "png",
    CODEC_TYPE_VIDEO,
    CODEC_ID_PNG,
    sizeof(PNGContext),
    /*.init=*/common_init,
    /*.encode=*/NULL,
    /*.close=*/NULL, //decode_end
    /*.decode=*/decode_frame,
    /*.capabilities=*/0, //CODEC_CAP_DR1 | CODEC_CAP_DRAW_HORIZ_BAND
    /*.next=*/NULL,
    /*.flush=*/NULL,
};

#ifdef CONFIG_ENCODERS
AVCodec png_encoder = {
    "png",
    CODEC_TYPE_VIDEO,
    CODEC_ID_PNG,
    sizeof(PNGContext),
    /*.init=*/common_init,
    /*.encode=*/encode_frame,
    /*.close=*/NULL, //encode_end
    /*.decode=*/NULL,
    /*.capabilities=*/0,
    /*.next=*/NULL,
    /*.flush=*/NULL,
    /*.supported_framerates=*/NULL,
#if __STDC_VERSION >= 199901L
    .pix_fmts= (enum PixelFormat[]){PIX_FMT_RGB24, PIX_FMT_RGB32, PIX_FMT_PAL8, PIX_FMT_GRAY8, PIX_FMT_MONOBLACK, -1},
#endif
};
#endif