yading@10: /*
yading@10:  * Microsoft Video-1 Decoder
yading@10:  * Copyright (C) 2003 the ffmpeg project
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * Microsoft Video-1 Decoder by Mike Melanson (melanson@pcisys.net)
yading@10:  * For more information about the MS Video-1 format, visit:
yading@10:  *   http://www.pcisys.net/~melanson/codecs/
yading@10:  *
yading@10:  */
yading@10: 
yading@10: #include <stdio.h>
yading@10: #include <stdlib.h>
yading@10: #include <string.h>
yading@10: 
yading@10: #include "libavutil/internal.h"
yading@10: #include "libavutil/intreadwrite.h"
yading@10: #include "avcodec.h"
yading@10: #include "internal.h"
yading@10: 
yading@10: #define PALETTE_COUNT 256
yading@10: #define CHECK_STREAM_PTR(n) \
yading@10:   if ((stream_ptr + n) > s->size ) { \
yading@10:     av_log(s->avctx, AV_LOG_ERROR, " MS Video-1 warning: stream_ptr out of bounds (%d >= %d)\n", \
yading@10:       stream_ptr + n, s->size); \
yading@10:     return; \
yading@10:   }
yading@10: 
yading@10: typedef struct Msvideo1Context {
yading@10: 
yading@10:     AVCodecContext *avctx;
yading@10:     AVFrame frame;
yading@10: 
yading@10:     const unsigned char *buf;
yading@10:     int size;
yading@10: 
yading@10:     int mode_8bit;  /* if it's not 8-bit, it's 16-bit */
yading@10: 
yading@10:     uint32_t pal[256];
yading@10: } Msvideo1Context;
yading@10: 
yading@10: static av_cold int msvideo1_decode_init(AVCodecContext *avctx)
yading@10: {
yading@10:     Msvideo1Context *s = avctx->priv_data;
yading@10: 
yading@10:     s->avctx = avctx;
yading@10: 
yading@10:     /* figure out the colorspace based on the presence of a palette */
yading@10:     if (s->avctx->bits_per_coded_sample == 8) {
yading@10:         s->mode_8bit = 1;
yading@10:         avctx->pix_fmt = AV_PIX_FMT_PAL8;
yading@10:     } else {
yading@10:         s->mode_8bit = 0;
yading@10:         avctx->pix_fmt = AV_PIX_FMT_RGB555;
yading@10:     }
yading@10: 
yading@10:     avcodec_get_frame_defaults(&s->frame);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static void msvideo1_decode_8bit(Msvideo1Context *s)
yading@10: {
yading@10:     int block_ptr, pixel_ptr;
yading@10:     int total_blocks;
yading@10:     int pixel_x, pixel_y;  /* pixel width and height iterators */
yading@10:     int block_x, block_y;  /* block width and height iterators */
yading@10:     int blocks_wide, blocks_high;  /* width and height in 4x4 blocks */
yading@10:     int block_inc;
yading@10:     int row_dec;
yading@10: 
yading@10:     /* decoding parameters */
yading@10:     int stream_ptr;
yading@10:     unsigned char byte_a, byte_b;
yading@10:     unsigned short flags;
yading@10:     int skip_blocks;
yading@10:     unsigned char colors[8];
yading@10:     unsigned char *pixels = s->frame.data[0];
yading@10:     int stride = s->frame.linesize[0];
yading@10: 
yading@10:     stream_ptr = 0;
yading@10:     skip_blocks = 0;
yading@10:     blocks_wide = s->avctx->width / 4;
yading@10:     blocks_high = s->avctx->height / 4;
yading@10:     total_blocks = blocks_wide * blocks_high;
yading@10:     block_inc = 4;
yading@10:     row_dec = stride + 4;
yading@10: 
yading@10:     for (block_y = blocks_high; block_y > 0; block_y--) {
yading@10:         block_ptr = ((block_y * 4) - 1) * stride;
yading@10:         for (block_x = blocks_wide; block_x > 0; block_x--) {
yading@10:             /* check if this block should be skipped */
yading@10:             if (skip_blocks) {
yading@10:                 block_ptr += block_inc;
yading@10:                 skip_blocks--;
yading@10:                 total_blocks--;
yading@10:                 continue;
yading@10:             }
yading@10: 
yading@10:             pixel_ptr = block_ptr;
yading@10: 
yading@10:             /* get the next two bytes in the encoded data stream */
yading@10:             CHECK_STREAM_PTR(2);
yading@10:             byte_a = s->buf[stream_ptr++];
yading@10:             byte_b = s->buf[stream_ptr++];
yading@10: 
yading@10:             /* check if the decode is finished */
yading@10:             if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0))
yading@10:                 return;
yading@10:             else if ((byte_b & 0xFC) == 0x84) {
yading@10:                 /* skip code, but don't count the current block */
yading@10:                 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
yading@10:             } else if (byte_b < 0x80) {
yading@10:                 /* 2-color encoding */
yading@10:                 flags = (byte_b << 8) | byte_a;
yading@10: 
yading@10:                 CHECK_STREAM_PTR(2);
yading@10:                 colors[0] = s->buf[stream_ptr++];
yading@10:                 colors[1] = s->buf[stream_ptr++];
yading@10: 
yading@10:                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
yading@10:                     for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
yading@10:                         pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
yading@10:                     pixel_ptr -= row_dec;
yading@10:                 }
yading@10:             } else if (byte_b >= 0x90) {
yading@10:                 /* 8-color encoding */
yading@10:                 flags = (byte_b << 8) | byte_a;
yading@10: 
yading@10:                 CHECK_STREAM_PTR(8);
yading@10:                 memcpy(colors, &s->buf[stream_ptr], 8);
yading@10:                 stream_ptr += 8;
yading@10: 
yading@10:                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
yading@10:                     for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
yading@10:                         pixels[pixel_ptr++] =
yading@10:                             colors[((pixel_y & 0x2) << 1) +
yading@10:                                 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
yading@10:                     pixel_ptr -= row_dec;
yading@10:                 }
yading@10:             } else {
yading@10:                 /* 1-color encoding */
yading@10:                 colors[0] = byte_a;
yading@10: 
yading@10:                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
yading@10:                     for (pixel_x = 0; pixel_x < 4; pixel_x++)
yading@10:                         pixels[pixel_ptr++] = colors[0];
yading@10:                     pixel_ptr -= row_dec;
yading@10:                 }
yading@10:             }
yading@10: 
yading@10:             block_ptr += block_inc;
yading@10:             total_blocks--;
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     /* make the palette available on the way out */
yading@10:     if (s->avctx->pix_fmt == AV_PIX_FMT_PAL8)
yading@10:         memcpy(s->frame.data[1], s->pal, AVPALETTE_SIZE);
yading@10: }
yading@10: 
yading@10: static void msvideo1_decode_16bit(Msvideo1Context *s)
yading@10: {
yading@10:     int block_ptr, pixel_ptr;
yading@10:     int total_blocks;
yading@10:     int pixel_x, pixel_y;  /* pixel width and height iterators */
yading@10:     int block_x, block_y;  /* block width and height iterators */
yading@10:     int blocks_wide, blocks_high;  /* width and height in 4x4 blocks */
yading@10:     int block_inc;
yading@10:     int row_dec;
yading@10: 
yading@10:     /* decoding parameters */
yading@10:     int stream_ptr;
yading@10:     unsigned char byte_a, byte_b;
yading@10:     unsigned short flags;
yading@10:     int skip_blocks;
yading@10:     unsigned short colors[8];
yading@10:     unsigned short *pixels = (unsigned short *)s->frame.data[0];
yading@10:     int stride = s->frame.linesize[0] / 2;
yading@10: 
yading@10:     stream_ptr = 0;
yading@10:     skip_blocks = 0;
yading@10:     blocks_wide = s->avctx->width / 4;
yading@10:     blocks_high = s->avctx->height / 4;
yading@10:     total_blocks = blocks_wide * blocks_high;
yading@10:     block_inc = 4;
yading@10:     row_dec = stride + 4;
yading@10: 
yading@10:     for (block_y = blocks_high; block_y > 0; block_y--) {
yading@10:         block_ptr = ((block_y * 4) - 1) * stride;
yading@10:         for (block_x = blocks_wide; block_x > 0; block_x--) {
yading@10:             /* check if this block should be skipped */
yading@10:             if (skip_blocks) {
yading@10:                 block_ptr += block_inc;
yading@10:                 skip_blocks--;
yading@10:                 total_blocks--;
yading@10:                 continue;
yading@10:             }
yading@10: 
yading@10:             pixel_ptr = block_ptr;
yading@10: 
yading@10:             /* get the next two bytes in the encoded data stream */
yading@10:             CHECK_STREAM_PTR(2);
yading@10:             byte_a = s->buf[stream_ptr++];
yading@10:             byte_b = s->buf[stream_ptr++];
yading@10: 
yading@10:             /* check if the decode is finished */
yading@10:             if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) {
yading@10:                 return;
yading@10:             } else if ((byte_b & 0xFC) == 0x84) {
yading@10:                 /* skip code, but don't count the current block */
yading@10:                 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
yading@10:             } else if (byte_b < 0x80) {
yading@10:                 /* 2- or 8-color encoding modes */
yading@10:                 flags = (byte_b << 8) | byte_a;
yading@10: 
yading@10:                 CHECK_STREAM_PTR(4);
yading@10:                 colors[0] = AV_RL16(&s->buf[stream_ptr]);
yading@10:                 stream_ptr += 2;
yading@10:                 colors[1] = AV_RL16(&s->buf[stream_ptr]);
yading@10:                 stream_ptr += 2;
yading@10: 
yading@10:                 if (colors[0] & 0x8000) {
yading@10:                     /* 8-color encoding */
yading@10:                     CHECK_STREAM_PTR(12);
yading@10:                     colors[2] = AV_RL16(&s->buf[stream_ptr]);
yading@10:                     stream_ptr += 2;
yading@10:                     colors[3] = AV_RL16(&s->buf[stream_ptr]);
yading@10:                     stream_ptr += 2;
yading@10:                     colors[4] = AV_RL16(&s->buf[stream_ptr]);
yading@10:                     stream_ptr += 2;
yading@10:                     colors[5] = AV_RL16(&s->buf[stream_ptr]);
yading@10:                     stream_ptr += 2;
yading@10:                     colors[6] = AV_RL16(&s->buf[stream_ptr]);
yading@10:                     stream_ptr += 2;
yading@10:                     colors[7] = AV_RL16(&s->buf[stream_ptr]);
yading@10:                     stream_ptr += 2;
yading@10: 
yading@10:                     for (pixel_y = 0; pixel_y < 4; pixel_y++) {
yading@10:                         for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
yading@10:                             pixels[pixel_ptr++] =
yading@10:                                 colors[((pixel_y & 0x2) << 1) +
yading@10:                                     (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
yading@10:                         pixel_ptr -= row_dec;
yading@10:                     }
yading@10:                 } else {
yading@10:                     /* 2-color encoding */
yading@10:                     for (pixel_y = 0; pixel_y < 4; pixel_y++) {
yading@10:                         for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
yading@10:                             pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
yading@10:                         pixel_ptr -= row_dec;
yading@10:                     }
yading@10:                 }
yading@10:             } else {
yading@10:                 /* otherwise, it's a 1-color block */
yading@10:                 colors[0] = (byte_b << 8) | byte_a;
yading@10: 
yading@10:                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
yading@10:                     for (pixel_x = 0; pixel_x < 4; pixel_x++)
yading@10:                         pixels[pixel_ptr++] = colors[0];
yading@10:                     pixel_ptr -= row_dec;
yading@10:                 }
yading@10:             }
yading@10: 
yading@10:             block_ptr += block_inc;
yading@10:             total_blocks--;
yading@10:         }
yading@10:     }
yading@10: }
yading@10: 
yading@10: static int msvideo1_decode_frame(AVCodecContext *avctx,
yading@10:                                 void *data, int *got_frame,
yading@10:                                 AVPacket *avpkt)
yading@10: {
yading@10:     const uint8_t *buf = avpkt->data;
yading@10:     int buf_size = avpkt->size;
yading@10:     Msvideo1Context *s = avctx->priv_data;
yading@10:     int ret;
yading@10: 
yading@10:     s->buf = buf;
yading@10:     s->size = buf_size;
yading@10: 
yading@10:     if ((ret = ff_reget_buffer(avctx, &s->frame)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     if (s->mode_8bit) {
yading@10:         const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
yading@10: 
yading@10:         if (pal) {
yading@10:             memcpy(s->pal, pal, AVPALETTE_SIZE);
yading@10:             s->frame.palette_has_changed = 1;
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     if (s->mode_8bit)
yading@10:         msvideo1_decode_8bit(s);
yading@10:     else
yading@10:         msvideo1_decode_16bit(s);
yading@10: 
yading@10:     if ((ret = av_frame_ref(data, &s->frame)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     *got_frame      = 1;
yading@10: 
yading@10:     /* report that the buffer was completely consumed */
yading@10:     return buf_size;
yading@10: }
yading@10: 
yading@10: static av_cold int msvideo1_decode_end(AVCodecContext *avctx)
yading@10: {
yading@10:     Msvideo1Context *s = avctx->priv_data;
yading@10: 
yading@10:     av_frame_unref(&s->frame);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: AVCodec ff_msvideo1_decoder = {
yading@10:     .name           = "msvideo1",
yading@10:     .type           = AVMEDIA_TYPE_VIDEO,
yading@10:     .id             = AV_CODEC_ID_MSVIDEO1,
yading@10:     .priv_data_size = sizeof(Msvideo1Context),
yading@10:     .init           = msvideo1_decode_init,
yading@10:     .close          = msvideo1_decode_end,
yading@10:     .decode         = msvideo1_decode_frame,
yading@10:     .capabilities   = CODEC_CAP_DR1,
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("Microsoft Video 1"),
yading@10: };