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->pal, AVPALETTE_SIZE); chunk_size = AV_RB32(&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 = AV_RB16(&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 = AV_RB32(&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 = ((AV_RB16(s->buf + stream_ptr ) & 0xFFF0) << 8) | (AV_RB16(s->buf + stream_ptr + 2) >> 4); color_flags_b = ((AV_RB16(s->buf + stream_ptr + 4) & 0xFFF0) << 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; } } }