PeerStreamer

/*

 * Quicktime Video (RPZA) Video Decoder

 * Copyright (C) 2003 the ffmpeg project

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * 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

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file

 * QT RPZA Video Decoder by Roberto Togni

 * 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

 * intended behavior as the ffmpeg documentation states that RGB555 pixels

 * shall be stored in native CPU endianness.

 */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "libavutil/intreadwrite.h"

#include "avcodec.h"

typedef struct RpzaContext {

    AVCodecContext *avctx;

    AVFrame frame;

    const unsigned char *buf;

    int size;

} RpzaContext;

#define ADVANCE_BLOCK() \

{ \

    pixel_ptr += 4; \

    if (pixel_ptr >= width) \

    { \

        pixel_ptr = 0; \

        row_ptr += stride * 4; \

    } \

    total_blocks--; \

    if (total_blocks < 0) \

    { \

        av_log(s->avctx, AV_LOG_ERROR, "warning: block counter just went negative (this should not happen)\n"); \

        return; \

    } \

}

static void rpza_decode_stream(RpzaContext *s)

{

    int width = s->avctx->width;

    int stride = s->frame.linesize[0] / 2;

    int row_inc = stride - 4;

    int stream_ptr = 0;

    int chunk_size;

    unsigned char opcode;

    int n_blocks;

    unsigned short colorA = 0, colorB;

    unsigned short color4[4];

    unsigned char index, idx;

    unsigned short ta, tb;

    unsigned short *pixels = (unsigned short *)s->frame.data[0];

    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 */

    if (s->buf[stream_ptr] != 0xe1)

        av_log(s->avctx, AV_LOG_ERROR, "First chunk byte is 0x%02x instead of 0xe1\n",

            s->buf[stream_ptr]);

    /* Get chunk size, ingnoring first byte */

    chunk_size = AV_RB32(&s->buf[stream_ptr]) & 0x00FFFFFF;

    stream_ptr += 4;

    /* If length mismatch use size from MOV file and try to decode anyway */

    if (chunk_size != s->size)

        av_log(s->avctx, AV_LOG_ERROR, "MOV chunk size != encoded chunk size; using MOV chunk size\n");

    chunk_size = s->size;

    /* Number of 4x4 blocks in frame. */

    total_blocks = ((s->avctx->width + 3) / 4) * ((s->avctx->height + 3) / 4);

    /* Process chunk data */

    while (stream_ptr < chunk_size) {

        opcode = s->buf[stream_ptr++]; /* Get opcode */

        n_blocks = (opcode & 0x1f) + 1; /* Extract block counter from opcode */

        /* If opcode MSbit is 0, we need more data to decide what to do */

        if ((opcode & 0x80) == 0) {

            colorA = (opcode << 8) | (s->buf[stream_ptr++]);

            opcode = 0;

            if ((s->buf[stream_ptr] & 0x80) != 0) {

                /* Must behave as opcode 110xxxxx, using colorA computed

                 * above. Use fake opcode 0x20 to enter switch block at

                 * the right place */

                opcode = 0x20;

                n_blocks = 1;

            }

        }

        switch (opcode & 0xe0) {

        /* Skip blocks */

        case 0x80:

            while (n_blocks--) {

              ADVANCE_BLOCK();

            }

            break;

        /* Fill blocks with one color */

        case 0xa0:

            colorA = AV_RB16 (&s->buf[stream_ptr]);

            stream_ptr += 2;

            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:

            colorA = AV_RB16 (&s->buf[stream_ptr]);

            stream_ptr += 2;

        case 0x20:

            colorB = AV_RB16 (&s->buf[stream_ptr]);

            stream_ptr += 2;

            /* 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);

            while (n_blocks--) {

                block_ptr = row_ptr + pixel_ptr;

                for (pixel_y = 0; pixel_y < 4; pixel_y++) {

                    index = s->buf[stream_ptr++];

                    for (pixel_x = 0; pixel_x < 4; pixel_x++){

                        idx = (index >> (2 * (3 - pixel_x))) & 0x03;

                        pixels[block_ptr] = color4[idx];

                        block_ptr++;

                    }

                    block_ptr += row_inc;

                }

                ADVANCE_BLOCK();

            }

            break;

        /* Fill block with 16 colors */

        case 0x00:

            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 */

                    if ((pixel_y != 0) || (pixel_x !=0)) {

                        colorA = AV_RB16 (&s->buf[stream_ptr]);

                        stream_ptr += 2;

                    }

                    pixels[block_ptr] = colorA;

                    block_ptr++;

                }

                block_ptr += row_inc;

            }

            ADVANCE_BLOCK();

            break;

        /* Unknown opcode */

        default:

            av_log(s->avctx, AV_LOG_ERROR, "Unknown opcode %d in rpza chunk."

                 " Skip remaining %d bytes of chunk data.\n", opcode,

                 chunk_size - stream_ptr);

            return;

        } /* Opcode switch */

    }

}

static av_cold int rpza_decode_init(AVCodecContext *avctx)

{

    RpzaContext *s = avctx->priv_data;

    s->avctx = avctx;

    avctx->pix_fmt = PIX_FMT_RGB555;

    s->frame.data[0] = NULL;

    return 0;

}

static int rpza_decode_frame(AVCodecContext *avctx,

                             void *data, int *data_size,

                             AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    RpzaContext *s = avctx->priv_data;

    s->buf = buf;

    s->size = buf_size;

    s->frame.reference = 1;

    s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;

    if (avctx->reget_buffer(avctx, &s->frame)) {

        av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");

        return -1;

    }

    rpza_decode_stream(s);

    *data_size = sizeof(AVFrame);

    *(AVFrame*)data = s->frame;

    /* always report that the buffer was completely consumed */

    return buf_size;

}

static av_cold int rpza_decode_end(AVCodecContext *avctx)

{

    RpzaContext *s = avctx->priv_data;

    if (s->frame.data[0])

        avctx->release_buffer(avctx, &s->frame);

    return 0;

}

AVCodec ff_rpza_decoder = {

    "rpza",

    AVMEDIA_TYPE_VIDEO,

    CODEC_ID_RPZA,

    sizeof(RpzaContext),

    rpza_decode_init,

    NULL,

    rpza_decode_end,

    rpza_decode_frame,

    CODEC_CAP_DR1,

    .long_name = NULL_IF_CONFIG_SMALL("QuickTime video (RPZA)"),

};