libavcodec/smc.c - nest-android-app/ffmpeg - Git at Google

 /*
  * Quicktime Graphics (SMC) 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 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 "libavutil/intreadwrite.h"
 #include "avcodec.h"
 #include "bytestream.h"
 #include "internal.h"

 #define CPAIR 2
 #define CQUAD 4
 #define COCTET 8

 #define COLORS_PER_TABLE 256

 typedef struct SmcContext {

     AVCodecContext *avctx;
     AVFrame *frame;

     GetByteContext gb;

     /* 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];

     uint32_t pal[256];
 } SmcContext;

 #define GET_BLOCK_COUNT() \
   (opcode & 0x10) ? (1 + bytestream2_get_byte(&s->gb)) : 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 < !!n_blocks) \
     { \
         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 chunk_size;
     int buf_size = bytestream2_size(&s->gb);
     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->pal, AVPALETTE_SIZE);

     bytestream2_skip(&s->gb, 1);
     chunk_size = bytestream2_get_be24(&s->gb);
     if (chunk_size != buf_size)
         av_log(s->avctx, AV_LOG_INFO, "warning: MOV chunk size != encoded chunk size (%d != %d); using MOV chunk size\n",
             chunk_size, buf_size);

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

     /* traverse through the blocks */
     while (total_blocks) {
         /* sanity checks */
         /* 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 = bytestream2_get_byte(&s->gb);
         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);
                 return;
             }

             /* 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);
                 return;
             }

             /* 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 = bytestream2_get_byte(&s->gb);

             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 = bytestream2_get_byte(&s->gb);
                     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 * bytestream2_get_byte(&s->gb);

             while (n_blocks--) {
                 color_flags = bytestream2_get_be16(&s->gb);
                 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 = bytestream2_get_byte(&s->gb);
                     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 * bytestream2_get_byte(&s->gb);

             while (n_blocks--) {
                 color_flags = bytestream2_get_be32(&s->gb);
                 /* 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 = bytestream2_get_byte(&s->gb);
                     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 * bytestream2_get_byte(&s->gb);

             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 */
                 int val1 = bytestream2_get_be16(&s->gb);
                 int val2 = bytestream2_get_be16(&s->gb);
                 int val3 = bytestream2_get_be16(&s->gb);
                 color_flags_a = ((val1 & 0xFFF0) << 8) | (val2 >> 4);
                 color_flags_b = ((val3 & 0xFFF0) << 8) |
                     ((val1 & 0x0F) << 8) | ((val2 & 0x0F) << 4) | (val3 & 0x0F);

                 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++] = bytestream2_get_byte(&s->gb);
                     }
                     block_ptr += row_inc;
                 }
                 ADVANCE_BLOCK();
             }
             break;

         case 0xF0:
             avpriv_request_sample(s->avctx, "0xF0 opcode");
             break;
         }
     }

     return;
 }

 static av_cold int smc_decode_init(AVCodecContext *avctx)
 {
     SmcContext *s = avctx->priv_data;

     s->avctx = avctx;
     avctx->pix_fmt = AV_PIX_FMT_PAL8;

     s->frame = av_frame_alloc();
     if (!s->frame)
         return AVERROR(ENOMEM);

     return 0;
 }

 static int smc_decode_frame(AVCodecContext *avctx,
                              void *data, int *got_frame,
                              AVPacket *avpkt)
 {
     const uint8_t *buf = avpkt->data;
     int buf_size = avpkt->size;
     SmcContext *s = avctx->priv_data;
     const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
     int ret;

     bytestream2_init(&s->gb, buf, buf_size);

     if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)
         return ret;

     if (pal) {
         s->frame->palette_has_changed = 1;
         memcpy(s->pal, pal, AVPALETTE_SIZE);
     }

     smc_decode_stream(s);

     *got_frame      = 1;
     if ((ret = av_frame_ref(data, s->frame)) < 0)
         return ret;

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

 static av_cold int smc_decode_end(AVCodecContext *avctx)
 {
     SmcContext *s = avctx->priv_data;

     av_frame_free(&s->frame);

     return 0;
 }

 AVCodec ff_smc_decoder = {
     .name           = "smc",
     .long_name      = NULL_IF_CONFIG_SMALL("QuickTime Graphics (SMC)"),
     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = AV_CODEC_ID_SMC,
     .priv_data_size = sizeof(SmcContext),
     .init           = smc_decode_init,
     .close          = smc_decode_end,
     .decode         = smc_decode_frame,
     .capabilities   = AV_CODEC_CAP_DR1,
 };
	/*
	* Quicktime Graphics (SMC) 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 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 "libavutil/intreadwrite.h"
	#include "avcodec.h"
	#include "bytestream.h"
	#include "internal.h"

	#define CPAIR 2
	#define CQUAD 4
	#define COCTET 8

	#define COLORS_PER_TABLE 256

	typedef struct SmcContext {

	AVCodecContext *avctx;
	AVFrame *frame;

	GetByteContext gb;

	/* 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];

	uint32_t pal[256];
	} SmcContext;

	#define GET_BLOCK_COUNT() \
	(opcode & 0x10) ? (1 + bytestream2_get_byte(&s->gb)) : 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 < !!n_blocks) \
	{ \
	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 chunk_size;
	int buf_size = bytestream2_size(&s->gb);
	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->pal, AVPALETTE_SIZE);

	bytestream2_skip(&s->gb, 1);
	chunk_size = bytestream2_get_be24(&s->gb);
	if (chunk_size != buf_size)
	av_log(s->avctx, AV_LOG_INFO, "warning: MOV chunk size != encoded chunk size (%d != %d); using MOV chunk size\n",
	chunk_size, buf_size);

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

	/* traverse through the blocks */
	while (total_blocks) {
	/* sanity checks */
	/* 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 = bytestream2_get_byte(&s->gb);
	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);
	return;
	}

	/* 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);
	return;
	}

	/* 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 = bytestream2_get_byte(&s->gb);

	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 = bytestream2_get_byte(&s->gb);
	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 * bytestream2_get_byte(&s->gb);

	while (n_blocks--) {
	color_flags = bytestream2_get_be16(&s->gb);
	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 = bytestream2_get_byte(&s->gb);
	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 * bytestream2_get_byte(&s->gb);

	while (n_blocks--) {
	color_flags = bytestream2_get_be32(&s->gb);
	/* 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 = bytestream2_get_byte(&s->gb);
	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 * bytestream2_get_byte(&s->gb);

	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 */
	int val1 = bytestream2_get_be16(&s->gb);
	int val2 = bytestream2_get_be16(&s->gb);
	int val3 = bytestream2_get_be16(&s->gb);
	color_flags_a = ((val1 & 0xFFF0) << 8) \| (val2 >> 4);
	color_flags_b = ((val3 & 0xFFF0) << 8) \|
	((val1 & 0x0F) << 8) \| ((val2 & 0x0F) << 4) \| (val3 & 0x0F);

	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++] = bytestream2_get_byte(&s->gb);
	}
	block_ptr += row_inc;
	}
	ADVANCE_BLOCK();
	}
	break;

	case 0xF0:
	avpriv_request_sample(s->avctx, "0xF0 opcode");
	break;
	}
	}

	return;
	}

	static av_cold int smc_decode_init(AVCodecContext *avctx)
	{
	SmcContext *s = avctx->priv_data;

	s->avctx = avctx;
	avctx->pix_fmt = AV_PIX_FMT_PAL8;

	s->frame = av_frame_alloc();
	if (!s->frame)
	return AVERROR(ENOMEM);

	return 0;
	}

	static int smc_decode_frame(AVCodecContext *avctx,
	void data, int got_frame,
	AVPacket *avpkt)
	{
	const uint8_t *buf = avpkt->data;
	int buf_size = avpkt->size;
	SmcContext *s = avctx->priv_data;
	const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
	int ret;

	bytestream2_init(&s->gb, buf, buf_size);

	if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)
	return ret;

	if (pal) {
	s->frame->palette_has_changed = 1;
	memcpy(s->pal, pal, AVPALETTE_SIZE);
	}

	smc_decode_stream(s);

	*got_frame = 1;
	if ((ret = av_frame_ref(data, s->frame)) < 0)
	return ret;

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

	static av_cold int smc_decode_end(AVCodecContext *avctx)
	{
	SmcContext *s = avctx->priv_data;

	av_frame_free(&s->frame);

	return 0;
	}

	AVCodec ff_smc_decoder = {
	.name = "smc",
	.long_name = NULL_IF_CONFIG_SMALL("QuickTime Graphics (SMC)"),
	.type = AVMEDIA_TYPE_VIDEO,
	.id = AV_CODEC_ID_SMC,
	.priv_data_size = sizeof(SmcContext),
	.init = smc_decode_init,
	.close = smc_decode_end,
	.decode = smc_decode_frame,
	.capabilities = AV_CODEC_CAP_DR1,
	};