PeerStreamer

/*

 * Quicktime Graphics (SMC) Video Decoder

 * Copyright (C) 2003 the ffmpeg project

 *

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

 *

 * This library 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 this library; if not, write to the Free Software

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

 *

 */

/**

 * @file smc.c

 * QT SMC Video Decoder by Mike Melanson (melanson@pcisys.net)

 * For more information about the SMC format, visit:

 *   http://www.pcisys.net/~melanson/codecs/

 *

 * The SMC decoder outputs PAL8 colorspace data.

 */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include "common.h"

#include "avcodec.h"

#include "dsputil.h"

#define CPAIR 2

#define CQUAD 4

#define COCTET 8

#define COLORS_PER_TABLE 256

typedef struct SmcContext {

    AVCodecContext *avctx;

    DSPContext dsp;

    AVFrame frame;

    unsigned char *buf;

    int size;

    /* SMC color tables */

    unsigned char color_pairs[COLORS_PER_TABLE * CPAIR];

    unsigned char color_quads[COLORS_PER_TABLE * CQUAD];

    unsigned char color_octets[COLORS_PER_TABLE * COCTET];

} SmcContext;

#define GET_BLOCK_COUNT() \

  (opcode & 0x10) ? (1 + s->buf[stream_ptr++]) : 1 + (opcode & 0x0F);

#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_INFO, "warning: block counter just went negative (this should not happen)\n"); \

        return; \

    } \

}

static void smc_decode_stream(SmcContext *s)

{

    int width = s->avctx->width;

    int height = s->avctx->height;

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

    int i;

    int stream_ptr = 0;

    int chunk_size;

    unsigned char opcode;

    int n_blocks;

    unsigned int color_flags;

    unsigned int color_flags_a;

    unsigned int color_flags_b;

    unsigned int flag_mask;

    unsigned char *pixels = s->frame.data[0];

    int image_size = height * s->frame.linesize[0];

    int row_ptr = 0;

    int pixel_ptr = 0;

    int pixel_x, pixel_y;

    int row_inc = stride - 4;

    int block_ptr;

    int prev_block_ptr;

    int prev_block_ptr1, prev_block_ptr2;

    int prev_block_flag;

    int total_blocks;

    int color_table_index;  /* indexes to color pair, quad, or octet tables */

    int pixel;

    int color_pair_index = 0;

    int color_quad_index = 0;

    int color_octet_index = 0;

    /* make the palette available */

    memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);

    if (s->avctx->palctrl->palette_changed) {

        s->frame.palette_has_changed = 1;

        s->avctx->palctrl->palette_changed = 0;

    }

    chunk_size = BE_32(&s->buf[stream_ptr]) & 0x00FFFFFF;

    stream_ptr += 4;

    if (chunk_size != s->size)

        av_log(s->avctx, AV_LOG_INFO, "warning: MOV chunk size != encoded chunk size (%d != %d); using MOV chunk size\n",

            chunk_size, s->size);

    chunk_size = s->size;

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

    /* traverse through the blocks */

    while (total_blocks) {

        /* sanity checks */

        /* make sure stream ptr hasn't gone out of bounds */

        if (stream_ptr > chunk_size) {

            av_log(s->avctx, AV_LOG_INFO, "SMC decoder just went out of bounds (stream ptr = %d, chunk size = %d)\n",

                stream_ptr, chunk_size);

            return;

        }

        /* make sure the row pointer hasn't gone wild */

        if (row_ptr >= image_size) {

            av_log(s->avctx, AV_LOG_INFO, "SMC decoder just went out of bounds (row ptr = %d, height = %d)\n",

                row_ptr, image_size);

            return;

        }

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

        switch (opcode & 0xF0) {

        /* skip n blocks */

        case 0x00:

        case 0x10:

            n_blocks = GET_BLOCK_COUNT();

            while (n_blocks--) {

                ADVANCE_BLOCK();

            }

            break;

        /* repeat last block n times */

        case 0x20:

        case 0x30:

            n_blocks = GET_BLOCK_COUNT();

            /* sanity check */

            if ((row_ptr == 0) && (pixel_ptr == 0)) {

                av_log(s->avctx, AV_LOG_INFO, "encountered repeat block opcode (%02X) but no blocks rendered yet\n",

                    opcode & 0xF0);

                break;

            }

            /* figure out where the previous block started */

            if (pixel_ptr == 0)

                prev_block_ptr1 =

                    (row_ptr - s->avctx->width * 4) + s->avctx->width - 4;

            else

                prev_block_ptr1 = row_ptr + pixel_ptr - 4;

            while (n_blocks--) {

                block_ptr = row_ptr + pixel_ptr;

                prev_block_ptr = prev_block_ptr1;

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

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

                        pixels[block_ptr++] = pixels[prev_block_ptr++];

                    }

                    block_ptr += row_inc;

                    prev_block_ptr += row_inc;

                }

                ADVANCE_BLOCK();

            }

            break;

        /* repeat previous pair of blocks n times */

        case 0x40:

        case 0x50:

            n_blocks = GET_BLOCK_COUNT();

            n_blocks *= 2;

            /* sanity check */

            if ((row_ptr == 0) && (pixel_ptr < 2 * 4)) {

                av_log(s->avctx, AV_LOG_INFO, "encountered repeat block opcode (%02X) but not enough blocks rendered yet\n",

                    opcode & 0xF0);

                break;

            }

            /* figure out where the previous 2 blocks started */

            if (pixel_ptr == 0)

                prev_block_ptr1 = (row_ptr - s->avctx->width * 4) +

                    s->avctx->width - 4 * 2;

            else if (pixel_ptr == 4)

                prev_block_ptr1 = (row_ptr - s->avctx->width * 4) + row_inc;

            else

                prev_block_ptr1 = row_ptr + pixel_ptr - 4 * 2;

            if (pixel_ptr == 0)

                prev_block_ptr2 = (row_ptr - s->avctx->width * 4) + row_inc;

            else

                prev_block_ptr2 = row_ptr + pixel_ptr - 4;

            prev_block_flag = 0;

            while (n_blocks--) {

                block_ptr = row_ptr + pixel_ptr;

                if (prev_block_flag)

                    prev_block_ptr = prev_block_ptr2;

                else

                    prev_block_ptr = prev_block_ptr1;

                prev_block_flag = !prev_block_flag;

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

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

                        pixels[block_ptr++] = pixels[prev_block_ptr++];

                    }

                    block_ptr += row_inc;

                    prev_block_ptr += row_inc;

                }

                ADVANCE_BLOCK();

            }

            break;

        /* 1-color block encoding */

        case 0x60:

        case 0x70:

            n_blocks = GET_BLOCK_COUNT();

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

            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++] = pixel;

                    }

                    block_ptr += row_inc;

                }

                ADVANCE_BLOCK();

            }

            break;

        /* 2-color block encoding */

        case 0x80:

        case 0x90:

            n_blocks = (opcode & 0x0F) + 1;

            /* figure out which color pair to use to paint the 2-color block */

            if ((opcode & 0xF0) == 0x80) {

                /* fetch the next 2 colors from bytestream and store in next

                 * available entry in the color pair table */

                for (i = 0; i < CPAIR; i++) {

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

                    color_table_index = CPAIR * color_pair_index + i;

                    s->color_pairs[color_table_index] = pixel;

                }

                /* this is the base index to use for this block */

                color_table_index = CPAIR * color_pair_index;

                color_pair_index++;

                /* wraparound */

                if (color_pair_index == COLORS_PER_TABLE)

                    color_pair_index = 0;

            } else

                color_table_index = CPAIR * s->buf[stream_ptr++];

            while (n_blocks--) {

                color_flags = BE_16(&s->buf[stream_ptr]);

                stream_ptr += 2;

                flag_mask = 0x8000;

                block_ptr = row_ptr + pixel_ptr;

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

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

                        if (color_flags & flag_mask)

                            pixel = color_table_index + 1;

                        else

                            pixel = color_table_index;

                        flag_mask >>= 1;

                        pixels[block_ptr++] = s->color_pairs[pixel];

                    }

                    block_ptr += row_inc;

                }

                ADVANCE_BLOCK();

            }

            break;

        /* 4-color block encoding */

        case 0xA0:

        case 0xB0:

            n_blocks = (opcode & 0x0F) + 1;

            /* figure out which color quad to use to paint the 4-color block */

            if ((opcode & 0xF0) == 0xA0) {

                /* fetch the next 4 colors from bytestream and store in next

                 * available entry in the color quad table */

                for (i = 0; i < CQUAD; i++) {

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

                    color_table_index = CQUAD * color_quad_index + i;

                    s->color_quads[color_table_index] = pixel;

                }

                /* this is the base index to use for this block */

                color_table_index = CQUAD * color_quad_index;

                color_quad_index++;

                /* wraparound */

                if (color_quad_index == COLORS_PER_TABLE)

                    color_quad_index = 0;

            } else

                color_table_index = CQUAD * s->buf[stream_ptr++];

            while (n_blocks--) {

                color_flags = BE_32(&s->buf[stream_ptr]);

                stream_ptr += 4;

                /* flag mask actually acts as a bit shift count here */

                flag_mask = 30;

                block_ptr = row_ptr + pixel_ptr;

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

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

                        pixel = color_table_index +

                            ((color_flags >> flag_mask) & 0x03);

                        flag_mask -= 2;

                        pixels[block_ptr++] = s->color_quads[pixel];

                    }

                    block_ptr += row_inc;

                }

                ADVANCE_BLOCK();

            }

            break;

        /* 8-color block encoding */

        case 0xC0:

        case 0xD0:

            n_blocks = (opcode & 0x0F) + 1;

            /* figure out which color octet to use to paint the 8-color block */

            if ((opcode & 0xF0) == 0xC0) {

                /* fetch the next 8 colors from bytestream and store in next

                 * available entry in the color octet table */

                for (i = 0; i < COCTET; i++) {

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

                    color_table_index = COCTET * color_octet_index + i;

                    s->color_octets[color_table_index] = pixel;

                }

                /* this is the base index to use for this block */

                color_table_index = COCTET * color_octet_index;

                color_octet_index++;

                /* wraparound */

                if (color_octet_index == COLORS_PER_TABLE)

                    color_octet_index = 0;

            } else

                color_table_index = COCTET * s->buf[stream_ptr++];

            while (n_blocks--) {

                /*

                  For this input of 6 hex bytes:

                    01 23 45 67 89 AB

                  Mangle it to this output:

                    flags_a = xx012456, flags_b = xx89A37B

                */

                /* build the color flags */

                color_flags_a = color_flags_b = 0;

                color_flags_a =

                    (s->buf[stream_ptr + 0] << 16) |

                    ((s->buf[stream_ptr + 1] & 0xF0) << 8) |

                    ((s->buf[stream_ptr + 2] & 0xF0) << 4) |

                    ((s->buf[stream_ptr + 2] & 0x0F) << 4) |

                    ((s->buf[stream_ptr + 3] & 0xF0) >> 4);

                color_flags_b =

                    (s->buf[stream_ptr + 4] << 16) |

                    ((s->buf[stream_ptr + 5] & 0xF0) << 8) |

                    ((s->buf[stream_ptr + 1] & 0x0F) << 8) |

                    ((s->buf[stream_ptr + 3] & 0x0F) << 4) |

                    (s->buf[stream_ptr + 5] & 0x0F);

                stream_ptr += 6;

                color_flags = color_flags_a;

                /* flag mask actually acts as a bit shift count here */

                flag_mask = 21;

                block_ptr = row_ptr + pixel_ptr;

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

                    /* reload flags at third row (iteration pixel_y == 2) */

                    if (pixel_y == 2) {

                        color_flags = color_flags_b;

                        flag_mask = 21;

                    }

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

                        pixel = color_table_index +

                            ((color_flags >> flag_mask) & 0x07);

                        flag_mask -= 3;

                        pixels[block_ptr++] = s->color_octets[pixel];

                    }

                    block_ptr += row_inc;

                }

                ADVANCE_BLOCK();

            }

            break;

        /* 16-color block encoding (every pixel is a different color) */

        case 0xE0:

            n_blocks = (opcode & 0x0F) + 1;

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

                    }

                    block_ptr += row_inc;

                }

                ADVANCE_BLOCK();

            }

            break;

        case 0xF0:

            av_log(s->avctx, AV_LOG_INFO, "0xF0 opcode seen in SMC chunk (contact the developers)\n");

            break;

        }

    }

}

static int smc_decode_init(AVCodecContext *avctx)

{

    SmcContext *s = (SmcContext *)avctx->priv_data;

    s->avctx = avctx;

    avctx->pix_fmt = PIX_FMT_PAL8;

    avctx->has_b_frames = 0;

    dsputil_init(&s->dsp, avctx);

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

    return 0;

}

static int smc_decode_frame(AVCodecContext *avctx,

                             void *data, int *data_size,

                             uint8_t *buf, int buf_size)

{

    SmcContext *s = (SmcContext *)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 | FF_BUFFER_HINTS_READABLE;

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

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

        return -1;

    }

    smc_decode_stream(s);

    *data_size = sizeof(AVFrame);

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

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

    return buf_size;

}

static int smc_decode_end(AVCodecContext *avctx)

{

    SmcContext *s = (SmcContext *)avctx->priv_data;

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

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

    return 0;

}

AVCodec smc_decoder = {

    "smc",

    CODEC_TYPE_VIDEO,

    CODEC_ID_SMC,

    sizeof(SmcContext),

    smc_decode_init,

    NULL,

    smc_decode_end,

    smc_decode_frame,

    CODEC_CAP_DR1,

};