/* * Microsoft Video-1 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ /** * @file msvideo1.c * Microsoft Video-1 Decoder by Mike Melanson (melanson@pcisys.net) * For more information about the MS Video-1 format, visit: * http://www.pcisys.net/~melanson/codecs/ * * This decoder outputs either PAL8 or RGB555 data, depending on the * whether a RGB palette was passed through palctrl; * if it's present, then the data is PAL8; RGB555 otherwise. */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include "common.h" #include "avcodec.h" #include "dsputil.h" #define PALETTE_COUNT 256 #define LE_16(x) ((((uint8_t*)(x))[1] << 8) | ((uint8_t*)(x))[0]) #define CHECK_STREAM_PTR(n) \ if ((stream_ptr + n) > s->size ) { \ av_log(s->avctx, AV_LOG_ERROR, " MS Video-1 warning: stream_ptr out of bounds (%d >= %d)\n", \ stream_ptr + n, s->size); \ return; \ } typedef struct Msvideo1Context { AVCodecContext *avctx; DSPContext dsp; AVFrame frame; unsigned char *buf; int size; int mode_8bit; /* if it's not 8-bit, it's 16-bit */ } Msvideo1Context; static int msvideo1_decode_init(AVCodecContext *avctx) { Msvideo1Context *s = (Msvideo1Context *)avctx->priv_data; s->avctx = avctx; /* figure out the colorspace based on the presence of a palette */ if (s->avctx->palctrl) { s->mode_8bit = 1; avctx->pix_fmt = PIX_FMT_PAL8; } else { s->mode_8bit = 0; avctx->pix_fmt = PIX_FMT_RGB555; } avctx->has_b_frames = 0; dsputil_init(&s->dsp, avctx); s->frame.data[0] = NULL; return 0; } static void msvideo1_decode_8bit(Msvideo1Context *s) { int block_ptr, pixel_ptr; int total_blocks; int pixel_x, pixel_y; /* pixel width and height iterators */ int block_x, block_y; /* block width and height iterators */ int blocks_wide, blocks_high; /* width and height in 4x4 blocks */ int block_inc; int row_dec; /* decoding parameters */ int stream_ptr; unsigned char byte_a, byte_b; unsigned short flags; int skip_blocks; unsigned char colors[8]; unsigned char *pixels = s->frame.data[0]; int stride = s->frame.linesize[0]; stream_ptr = 0; skip_blocks = 0; blocks_wide = s->avctx->width / 4; blocks_high = s->avctx->height / 4; total_blocks = blocks_wide * blocks_high; block_inc = 4; row_dec = stride + 4; for (block_y = blocks_high; block_y > 0; block_y--) { block_ptr = ((block_y * 4) - 1) * stride; for (block_x = blocks_wide; block_x > 0; block_x--) { /* check if this block should be skipped */ if (skip_blocks) { block_ptr += block_inc; skip_blocks--; total_blocks--; continue; } pixel_ptr = block_ptr; /* get the next two bytes in the encoded data stream */ CHECK_STREAM_PTR(2); byte_a = s->buf[stream_ptr++]; byte_b = s->buf[stream_ptr++]; /* check if the decode is finished */ if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) return; else if ((byte_b & 0xFC) == 0x84) { /* skip code, but don't count the current block */ skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1; } else if (byte_b < 0x80) { /* 2-color encoding */ flags = (byte_b << 8) | byte_a; CHECK_STREAM_PTR(2); colors[0] = s->buf[stream_ptr++]; colors[1] = s->buf[stream_ptr++]; for (pixel_y = 0; pixel_y < 4; pixel_y++) { for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1) pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1]; pixel_ptr -= row_dec; } } else if (byte_b >= 0x90) { /* 8-color encoding */ flags = (byte_b << 8) | byte_a; CHECK_STREAM_PTR(8); memcpy(colors, &s->buf[stream_ptr], 8); stream_ptr += 8; for (pixel_y = 0; pixel_y < 4; pixel_y++) { for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1) pixels[pixel_ptr++] = colors[((pixel_y & 0x2) << 1) + (pixel_x & 0x2) + ((flags & 0x1) ^ 1)]; pixel_ptr -= row_dec; } } else { /* 1-color encoding */ colors[0] = byte_a; for (pixel_y = 0; pixel_y < 4; pixel_y++) { for (pixel_x = 0; pixel_x < 4; pixel_x++) pixels[pixel_ptr++] = colors[0]; pixel_ptr -= row_dec; } } block_ptr += block_inc; total_blocks--; } } /* make the palette available on the way out */ if (s->avctx->pix_fmt == PIX_FMT_PAL8) { 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; } } } static void msvideo1_decode_16bit(Msvideo1Context *s) { int block_ptr, pixel_ptr; int total_blocks; int pixel_x, pixel_y; /* pixel width and height iterators */ int block_x, block_y; /* block width and height iterators */ int blocks_wide, blocks_high; /* width and height in 4x4 blocks */ int block_inc; int row_dec; /* decoding parameters */ int stream_ptr; unsigned char byte_a, byte_b; unsigned short flags; int skip_blocks; unsigned short colors[8]; unsigned short *pixels = (unsigned short *)s->frame.data[0]; int stride = s->frame.linesize[0] / 2; stream_ptr = 0; skip_blocks = 0; blocks_wide = s->avctx->width / 4; blocks_high = s->avctx->height / 4; total_blocks = blocks_wide * blocks_high; block_inc = 4; row_dec = stride + 4; for (block_y = blocks_high; block_y > 0; block_y--) { block_ptr = ((block_y * 4) - 1) * stride; for (block_x = blocks_wide; block_x > 0; block_x--) { /* check if this block should be skipped */ if (skip_blocks) { block_ptr += block_inc; skip_blocks--; total_blocks--; continue; } pixel_ptr = block_ptr; /* get the next two bytes in the encoded data stream */ CHECK_STREAM_PTR(2); byte_a = s->buf[stream_ptr++]; byte_b = s->buf[stream_ptr++]; /* check if the decode is finished */ if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) { return; } else if ((byte_b & 0xFC) == 0x84) { /* skip code, but don't count the current block */ skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1; } else if (byte_b < 0x80) { /* 2- or 8-color encoding modes */ flags = (byte_b << 8) | byte_a; CHECK_STREAM_PTR(4); colors[0] = LE_16(&s->buf[stream_ptr]); stream_ptr += 2; colors[1] = LE_16(&s->buf[stream_ptr]); stream_ptr += 2; if (colors[0] & 0x8000) { /* 8-color encoding */ CHECK_STREAM_PTR(12); colors[2] = LE_16(&s->buf[stream_ptr]); stream_ptr += 2; colors[3] = LE_16(&s->buf[stream_ptr]); stream_ptr += 2; colors[4] = LE_16(&s->buf[stream_ptr]); stream_ptr += 2; colors[5] = LE_16(&s->buf[stream_ptr]); stream_ptr += 2; colors[6] = LE_16(&s->buf[stream_ptr]); stream_ptr += 2; colors[7] = LE_16(&s->buf[stream_ptr]); stream_ptr += 2; for (pixel_y = 0; pixel_y < 4; pixel_y++) { for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1) pixels[pixel_ptr++] = colors[((pixel_y & 0x2) << 1) + (pixel_x & 0x2) + ((flags & 0x1) ^ 1)]; pixel_ptr -= row_dec; } } else { /* 2-color encoding */ for (pixel_y = 0; pixel_y < 4; pixel_y++) { for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1) pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1]; pixel_ptr -= row_dec; } } } else { /* otherwise, it's a 1-color block */ colors[0] = (byte_b << 8) | byte_a; for (pixel_y = 0; pixel_y < 4; pixel_y++) { for (pixel_x = 0; pixel_x < 4; pixel_x++) pixels[pixel_ptr++] = colors[0]; pixel_ptr -= row_dec; } } block_ptr += block_inc; total_blocks--; } } } static int msvideo1_decode_frame(AVCodecContext *avctx, void *data, int *data_size, uint8_t *buf, int buf_size) { Msvideo1Context *s = (Msvideo1Context *)avctx->priv_data; /* no supplementary picture */ if (buf_size == 0) return 0; 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(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n"); return -1; } if (s->mode_8bit) msvideo1_decode_8bit(s); else msvideo1_decode_16bit(s); *data_size = sizeof(AVFrame); *(AVFrame*)data = s->frame; /* report that the buffer was completely consumed */ return buf_size; } static int msvideo1_decode_end(AVCodecContext *avctx) { Msvideo1Context *s = (Msvideo1Context *)avctx->priv_data; if (s->frame.data[0]) avctx->release_buffer(avctx, &s->frame); return 0; } AVCodec msvideo1_decoder = { "msvideo1", CODEC_TYPE_VIDEO, CODEC_ID_MSVIDEO1, sizeof(Msvideo1Context), msvideo1_decode_init, NULL, msvideo1_decode_end, msvideo1_decode_frame, CODEC_CAP_DR1, };