rpza.c 8.66 KB
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/*
 * Quicktime Video (RPZA) Video Decoder
 * Copyright (C) 2003 the ffmpeg project
 *
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 * This file is part of Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */

/**
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 * @file
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 * QT RPZA Video Decoder by Roberto Togni
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 * For more information about the RPZA format, visit:
 *   http://www.pcisys.net/~melanson/codecs/
 *
 * The RPZA decoder outputs RGB555 colorspace data.
 *
 * Note that this decoder reads big endian RGB555 pixel values from the
 * bytestream, arranges them in the host's endian order, and outputs
 * them to the final rendered map in the same host endian order. This is
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 * intended behavior as the libavcodec documentation states that RGB555
 * pixels shall be stored in native CPU endianness.
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 */

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#include <stdint.h>
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>

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#include "libavutil/internal.h"
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#include "avcodec.h"
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#include "bytestream.h"
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#include "internal.h"
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typedef struct RpzaContext {

    AVCodecContext *avctx;
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    AVFrame *frame;
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    GetByteContext gb;
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} RpzaContext;

#define ADVANCE_BLOCK() \
{ \
    pixel_ptr += 4; \
    if (pixel_ptr >= width) \
    { \
        pixel_ptr = 0; \
        row_ptr += stride * 4; \
    } \
    total_blocks--; \
    if (total_blocks < 0) \
    { \
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        av_log(s->avctx, AV_LOG_ERROR, "warning: block counter just went negative (this should not happen)\n"); \
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        return; \
    } \
}

static void rpza_decode_stream(RpzaContext *s)
{
    int width = s->avctx->width;
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    int stride = s->frame->linesize[0] / 2;
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    int row_inc = stride - 4;
    int chunk_size;
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    uint16_t colorA = 0, colorB;
    uint16_t color4[4];
    uint16_t ta, tb;
    uint16_t *pixels = (uint16_t *)s->frame->data[0];
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    int row_ptr = 0;
    int pixel_ptr = 0;
    int block_ptr;
    int pixel_x, pixel_y;
    int total_blocks;

    /* First byte is always 0xe1. Warn if it's different */
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    if (bytestream2_peek_byte(&s->gb) != 0xe1)
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        av_log(s->avctx, AV_LOG_ERROR, "First chunk byte is 0x%02x instead of 0xe1\n",
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               bytestream2_peek_byte(&s->gb));
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    /* Get chunk size, ingnoring first byte */
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    chunk_size = bytestream2_get_be32(&s->gb) & 0x00FFFFFF;
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    /* If length mismatch use size from MOV file and try to decode anyway */
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    if (chunk_size != bytestream2_get_bytes_left(&s->gb) - 4)
        av_log(s->avctx, AV_LOG_WARNING, "MOV chunk size != encoded chunk size\n");
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    /* Number of 4x4 blocks in frame. */
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    total_blocks = ((s->avctx->width + 3) / 4) * ((s->avctx->height + 3) / 4);
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    /* Process chunk data */
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    while (bytestream2_get_bytes_left(&s->gb)) {
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        uint8_t opcode = bytestream2_get_byte(&s->gb); /* Get opcode */
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        int n_blocks = (opcode & 0x1f) + 1; /* Extract block counter from opcode */
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        /* If opcode MSbit is 0, we need more data to decide what to do */
        if ((opcode & 0x80) == 0) {
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            colorA = (opcode << 8) | bytestream2_get_byte(&s->gb);
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            opcode = 0;
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            if ((bytestream2_peek_byte(&s->gb) & 0x80) != 0) {
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                /* Must behave as opcode 110xxxxx, using colorA computed
                 * above. Use fake opcode 0x20 to enter switch block at
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                 * the right place */
                opcode = 0x20;
                n_blocks = 1;
            }
        }

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        n_blocks = FFMIN(n_blocks, total_blocks);

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        switch (opcode & 0xe0) {

        /* Skip blocks */
        case 0x80:
            while (n_blocks--) {
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              ADVANCE_BLOCK();
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            }
            break;

        /* Fill blocks with one color */
        case 0xa0:
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            colorA = bytestream2_get_be16(&s->gb);
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            while (n_blocks--) {
                block_ptr = row_ptr + pixel_ptr;
                for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                    for (pixel_x = 0; pixel_x < 4; pixel_x++){
                        pixels[block_ptr] = colorA;
                        block_ptr++;
                    }
                    block_ptr += row_inc;
                }
                ADVANCE_BLOCK();
            }
            break;

        /* Fill blocks with 4 colors */
        case 0xc0:
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            colorA = bytestream2_get_be16(&s->gb);
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        case 0x20:
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            colorB = bytestream2_get_be16(&s->gb);
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            /* sort out the colors */
            color4[0] = colorB;
            color4[1] = 0;
            color4[2] = 0;
            color4[3] = colorA;

            /* red components */
            ta = (colorA >> 10) & 0x1F;
            tb = (colorB >> 10) & 0x1F;
            color4[1] |= ((11 * ta + 21 * tb) >> 5) << 10;
            color4[2] |= ((21 * ta + 11 * tb) >> 5) << 10;

            /* green components */
            ta = (colorA >> 5) & 0x1F;
            tb = (colorB >> 5) & 0x1F;
            color4[1] |= ((11 * ta + 21 * tb) >> 5) << 5;
            color4[2] |= ((21 * ta + 11 * tb) >> 5) << 5;

            /* blue components */
            ta = colorA & 0x1F;
            tb = colorB & 0x1F;
            color4[1] |= ((11 * ta + 21 * tb) >> 5);
            color4[2] |= ((21 * ta + 11 * tb) >> 5);

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            if (bytestream2_get_bytes_left(&s->gb) < n_blocks * 4)
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                return;
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            while (n_blocks--) {
                block_ptr = row_ptr + pixel_ptr;
                for (pixel_y = 0; pixel_y < 4; pixel_y++) {
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                    uint8_t index = bytestream2_get_byteu(&s->gb);
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                    for (pixel_x = 0; pixel_x < 4; pixel_x++){
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                        uint8_t idx = (index >> (2 * (3 - pixel_x))) & 0x03;
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                        pixels[block_ptr] = color4[idx];
                        block_ptr++;
                    }
                    block_ptr += row_inc;
                }
                ADVANCE_BLOCK();
            }
            break;

        /* Fill block with 16 colors */
        case 0x00:
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            if (bytestream2_get_bytes_left(&s->gb) < 30)
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                return;
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            block_ptr = row_ptr + pixel_ptr;
            for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                for (pixel_x = 0; pixel_x < 4; pixel_x++){
                    /* We already have color of upper left pixel */
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                    if ((pixel_y != 0) || (pixel_x != 0))
                        colorA = bytestream2_get_be16u(&s->gb);
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                    pixels[block_ptr] = colorA;
                    block_ptr++;
                }
                block_ptr += row_inc;
            }
            ADVANCE_BLOCK();
            break;

        /* Unknown opcode */
        default:
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            av_log(s->avctx, AV_LOG_ERROR, "Unknown opcode %d in rpza chunk."
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                 " Skip remaining %d bytes of chunk data.\n", opcode,
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                 bytestream2_get_bytes_left(&s->gb));
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            return;
        } /* Opcode switch */
    }
}

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static av_cold int rpza_decode_init(AVCodecContext *avctx)
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{
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    RpzaContext *s = avctx->priv_data;
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    s->avctx = avctx;
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    avctx->pix_fmt = AV_PIX_FMT_RGB555;
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    s->frame = av_frame_alloc();
    if (!s->frame)
        return AVERROR(ENOMEM);
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    return 0;
}

static int rpza_decode_frame(AVCodecContext *avctx,
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                             void *data, int *got_frame,
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                             AVPacket *avpkt)
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{
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    RpzaContext *s = avctx->priv_data;
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    int ret;
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    bytestream2_init(&s->gb, avpkt->data, avpkt->size);
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    if ((ret = ff_reget_buffer(avctx, s->frame)) < 0) {
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        av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
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        return ret;
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    }

    rpza_decode_stream(s);

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    if ((ret = av_frame_ref(data, s->frame)) < 0)
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        return ret;

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    *got_frame      = 1;
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    /* always report that the buffer was completely consumed */
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    return avpkt->size;
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}

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static av_cold int rpza_decode_end(AVCodecContext *avctx)
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{
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    RpzaContext *s = avctx->priv_data;
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    av_frame_free(&s->frame);
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    return 0;
}

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AVCodec ff_rpza_decoder = {
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    .name           = "rpza",
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    .long_name      = NULL_IF_CONFIG_SMALL("QuickTime video (RPZA)"),
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    .type           = AVMEDIA_TYPE_VIDEO,
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    .id             = AV_CODEC_ID_RPZA,
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    .priv_data_size = sizeof(RpzaContext),
    .init           = rpza_decode_init,
    .close          = rpza_decode_end,
    .decode         = rpza_decode_frame,
    .capabilities   = CODEC_CAP_DR1,
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};