/* * Microsoft Video-1 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 * 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/ */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include "libavutil/internal.h" #include "libavutil/intreadwrite.h" #include "avcodec.h" #include "decode.h" #include "internal.h" #define PALETTE_COUNT 256 #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; AVFrame *frame; const unsigned char *buf; int size; int mode_8bit; /* if it's not 8-bit, it's 16-bit */ uint32_t pal[256]; } Msvideo1Context; static av_cold int msvideo1_decode_init(AVCodecContext *avctx) { Msvideo1Context *s = avctx->priv_data; s->avctx = avctx; if (avctx->width < 4 || avctx->height < 4) return AVERROR_INVALIDDATA; /* figure out the colorspace based on the presence of a palette */ if (s->avctx->bits_per_coded_sample == 8) { s->mode_8bit = 1; avctx->pix_fmt = AV_PIX_FMT_PAL8; if (avctx->extradata_size >= AVPALETTE_SIZE) memcpy(s->pal, avctx->extradata, AVPALETTE_SIZE); } else { s->mode_8bit = 0; avctx->pix_fmt = AV_PIX_FMT_RGB555; } s->frame = av_frame_alloc(); if (!s->frame) return AVERROR(ENOMEM); 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 == AV_PIX_FMT_PAL8) memcpy(s->frame->data[1], s->pal, AVPALETTE_SIZE); } 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] = AV_RL16(&s->buf[stream_ptr]); stream_ptr += 2; colors[1] = AV_RL16(&s->buf[stream_ptr]); stream_ptr += 2; if (colors[0] & 0x8000) { /* 8-color encoding */ CHECK_STREAM_PTR(12); colors[2] = AV_RL16(&s->buf[stream_ptr]); stream_ptr += 2; colors[3] = AV_RL16(&s->buf[stream_ptr]); stream_ptr += 2; colors[4] = AV_RL16(&s->buf[stream_ptr]); stream_ptr += 2; colors[5] = AV_RL16(&s->buf[stream_ptr]); stream_ptr += 2; colors[6] = AV_RL16(&s->buf[stream_ptr]); stream_ptr += 2; colors[7] = AV_RL16(&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 *got_frame, AVPacket *avpkt) { const uint8_t *buf = avpkt->data; int buf_size = avpkt->size; Msvideo1Context *s = avctx->priv_data; int ret; s->buf = buf; s->size = buf_size; // Discard frame if its smaller than the minimum frame size if (buf_size < (avctx->width/4) * (avctx->height/4) / 512) { av_log(avctx, AV_LOG_ERROR, "Packet is too small\n"); return AVERROR_INVALIDDATA; } if ((ret = ff_reget_buffer(avctx, s->frame, 0)) < 0) return ret; if (s->mode_8bit) { s->frame->palette_has_changed = ff_copy_palette(s->pal, avpkt, avctx); } if (s->mode_8bit) msvideo1_decode_8bit(s); else msvideo1_decode_16bit(s); if ((ret = av_frame_ref(data, s->frame)) < 0) return ret; *got_frame = 1; /* report that the buffer was completely consumed */ return buf_size; } static av_cold int msvideo1_decode_end(AVCodecContext *avctx) { Msvideo1Context *s = avctx->priv_data; av_frame_free(&s->frame); return 0; } AVCodec ff_msvideo1_decoder = { .name = "msvideo1", .long_name = NULL_IF_CONFIG_SMALL("Microsoft Video 1"), .type = AVMEDIA_TYPE_VIDEO, .id = AV_CODEC_ID_MSVIDEO1, .priv_data_size = sizeof(Msvideo1Context), .init = msvideo1_decode_init, .close = msvideo1_decode_end, .decode = msvideo1_decode_frame, .capabilities = AV_CODEC_CAP_DR1, };