yading@10: /*
yading@10:  * Wing Commander/Xan Video Decoder
yading@10:  * Copyright (C) 2011 Konstantin Shishkov
yading@10:  * based on work by Mike Melanson
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: #include "avcodec.h"
yading@10: #include "libavutil/intreadwrite.h"
yading@10: #include "libavutil/mem.h"
yading@10: #include "bytestream.h"
yading@10: #define BITSTREAM_READER_LE
yading@10: #include "get_bits.h"
yading@10: #include "internal.h"
yading@10: 
yading@10: typedef struct XanContext {
yading@10:     AVCodecContext *avctx;
yading@10:     AVFrame *pic;
yading@10: 
yading@10:     uint8_t *y_buffer;
yading@10:     uint8_t *scratch_buffer;
yading@10:     int     buffer_size;
yading@10:     GetByteContext gb;
yading@10: } XanContext;
yading@10: 
yading@10: static av_cold int xan_decode_end(AVCodecContext *avctx);
yading@10: 
yading@10: static av_cold int xan_decode_init(AVCodecContext *avctx)
yading@10: {
yading@10:     XanContext *s = avctx->priv_data;
yading@10: 
yading@10:     s->avctx = avctx;
yading@10: 
yading@10:     avctx->pix_fmt = AV_PIX_FMT_YUV420P;
yading@10: 
yading@10:     if (avctx->height < 8) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "Invalid frame height: %d.\n", avctx->height);
yading@10:         return AVERROR(EINVAL);
yading@10:     }
yading@10: 
yading@10:     s->buffer_size = avctx->width * avctx->height;
yading@10:     s->y_buffer = av_malloc(s->buffer_size);
yading@10:     if (!s->y_buffer)
yading@10:         return AVERROR(ENOMEM);
yading@10:     s->scratch_buffer = av_malloc(s->buffer_size + 130);
yading@10:     if (!s->scratch_buffer) {
yading@10:         xan_decode_end(avctx);
yading@10:         return AVERROR(ENOMEM);
yading@10:     }
yading@10: 
yading@10:     s->pic = av_frame_alloc();
yading@10:     if (!s->pic) {
yading@10:         xan_decode_end(avctx);
yading@10:         return AVERROR(ENOMEM);
yading@10:     }
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int xan_unpack_luma(XanContext *s,
yading@10:                            uint8_t *dst, const int dst_size)
yading@10: {
yading@10:     int tree_size, eof;
yading@10:     int bits, mask;
yading@10:     int tree_root, node;
yading@10:     const uint8_t *dst_end = dst + dst_size;
yading@10:     GetByteContext tree = s->gb;
yading@10:     int start_off = bytestream2_tell(&tree);
yading@10: 
yading@10:     tree_size = bytestream2_get_byte(&s->gb);
yading@10:     eof       = bytestream2_get_byte(&s->gb);
yading@10:     tree_root = eof + tree_size;
yading@10:     bytestream2_skip(&s->gb, tree_size * 2);
yading@10: 
yading@10:     node = tree_root;
yading@10:     bits = bytestream2_get_byte(&s->gb);
yading@10:     mask = 0x80;
yading@10:     for (;;) {
yading@10:         int bit = !!(bits & mask);
yading@10:         mask >>= 1;
yading@10:         bytestream2_seek(&tree, start_off + node*2 + bit - eof * 2, SEEK_SET);
yading@10:         node = bytestream2_get_byte(&tree);
yading@10:         if (node == eof)
yading@10:             break;
yading@10:         if (node < eof) {
yading@10:             *dst++ = node;
yading@10:             if (dst > dst_end)
yading@10:                 break;
yading@10:             node = tree_root;
yading@10:         }
yading@10:         if (!mask) {
yading@10:             if (bytestream2_get_bytes_left(&s->gb) <= 0)
yading@10:                 break;
yading@10:             bits = bytestream2_get_byteu(&s->gb);
yading@10:             mask = 0x80;
yading@10:         }
yading@10:     }
yading@10:     return dst != dst_end ? AVERROR_INVALIDDATA : 0;
yading@10: }
yading@10: 
yading@10: /* almost the same as in xan_wc3 decoder */
yading@10: static int xan_unpack(XanContext *s,
yading@10:                       uint8_t *dest, const int dest_len)
yading@10: {
yading@10:     uint8_t opcode;
yading@10:     int size;
yading@10:     uint8_t *orig_dest = dest;
yading@10:     const uint8_t *dest_end = dest + dest_len;
yading@10: 
yading@10:     while (dest < dest_end) {
yading@10:         if (bytestream2_get_bytes_left(&s->gb) <= 0)
yading@10:             return AVERROR_INVALIDDATA;
yading@10: 
yading@10:         opcode = bytestream2_get_byteu(&s->gb);
yading@10: 
yading@10:         if (opcode < 0xe0) {
yading@10:             int size2, back;
yading@10:             if ((opcode & 0x80) == 0) {
yading@10:                 size  = opcode & 3;
yading@10:                 back  = ((opcode & 0x60) << 3) + bytestream2_get_byte(&s->gb) + 1;
yading@10:                 size2 = ((opcode & 0x1c) >> 2) + 3;
yading@10:             } else if ((opcode & 0x40) == 0) {
yading@10:                 size  = bytestream2_peek_byte(&s->gb) >> 6;
yading@10:                 back  = (bytestream2_get_be16(&s->gb) & 0x3fff) + 1;
yading@10:                 size2 = (opcode & 0x3f) + 4;
yading@10:             } else {
yading@10:                 size  = opcode & 3;
yading@10:                 back  = ((opcode & 0x10) << 12) + bytestream2_get_be16(&s->gb) + 1;
yading@10:                 size2 = ((opcode & 0x0c) <<  6) + bytestream2_get_byte(&s->gb) + 5;
yading@10:                 if (size + size2 > dest_end - dest)
yading@10:                     break;
yading@10:             }
yading@10:             if (dest + size + size2 > dest_end ||
yading@10:                 dest - orig_dest + size < back)
yading@10:                 return AVERROR_INVALIDDATA;
yading@10:             bytestream2_get_buffer(&s->gb, dest, size);
yading@10:             dest += size;
yading@10:             av_memcpy_backptr(dest, back, size2);
yading@10:             dest += size2;
yading@10:         } else {
yading@10:             int finish = opcode >= 0xfc;
yading@10: 
yading@10:             size = finish ? opcode & 3 : ((opcode & 0x1f) << 2) + 4;
yading@10:             if (dest_end - dest < size)
yading@10:                 return AVERROR_INVALIDDATA;
yading@10:             bytestream2_get_buffer(&s->gb, dest, size);
yading@10:             dest += size;
yading@10:             if (finish)
yading@10:                 break;
yading@10:         }
yading@10:     }
yading@10:     return dest - orig_dest;
yading@10: }
yading@10: 
yading@10: static int xan_decode_chroma(AVCodecContext *avctx, unsigned chroma_off)
yading@10: {
yading@10:     XanContext *s = avctx->priv_data;
yading@10:     uint8_t *U, *V;
yading@10:     int val, uval, vval;
yading@10:     int i, j;
yading@10:     const uint8_t *src, *src_end;
yading@10:     const uint8_t *table;
yading@10:     int mode, offset, dec_size, table_size;
yading@10: 
yading@10:     if (!chroma_off)
yading@10:         return 0;
yading@10:     if (chroma_off + 4 >= bytestream2_get_bytes_left(&s->gb)) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "Invalid chroma block position\n");
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10:     bytestream2_seek(&s->gb, chroma_off + 4, SEEK_SET);
yading@10:     mode        = bytestream2_get_le16(&s->gb);
yading@10:     table       = s->gb.buffer;
yading@10:     table_size  = bytestream2_get_le16(&s->gb);
yading@10:     offset      = table_size * 2;
yading@10:     table_size += 1;
yading@10: 
yading@10:     if (offset >= bytestream2_get_bytes_left(&s->gb)) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "Invalid chroma block offset\n");
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     bytestream2_skip(&s->gb, offset);
yading@10:     memset(s->scratch_buffer, 0, s->buffer_size);
yading@10:     dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size);
yading@10:     if (dec_size < 0) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "Chroma unpacking failed\n");
yading@10:         return dec_size;
yading@10:     }
yading@10: 
yading@10:     U = s->pic->data[1];
yading@10:     V = s->pic->data[2];
yading@10:     src     = s->scratch_buffer;
yading@10:     src_end = src + dec_size;
yading@10:     if (mode) {
yading@10:         for (j = 0; j < avctx->height >> 1; j++) {
yading@10:             for (i = 0; i < avctx->width >> 1; i++) {
yading@10:                 if (src_end - src < 1)
yading@10:                     return 0;
yading@10:                 val = *src++;
yading@10:                 if (val) {
yading@10:                     if (val >= table_size)
yading@10:                         return AVERROR_INVALIDDATA;
yading@10:                     val  = AV_RL16(table + (val << 1));
yading@10:                     uval = (val >> 3) & 0xF8;
yading@10:                     vval = (val >> 8) & 0xF8;
yading@10:                     U[i] = uval | (uval >> 5);
yading@10:                     V[i] = vval | (vval >> 5);
yading@10:                 }
yading@10:             }
yading@10:             U += s->pic->linesize[1];
yading@10:             V += s->pic->linesize[2];
yading@10:         }
yading@10:         if (avctx->height & 1) {
yading@10:             memcpy(U, U - s->pic->linesize[1], avctx->width >> 1);
yading@10:             memcpy(V, V - s->pic->linesize[2], avctx->width >> 1);
yading@10:         }
yading@10:     } else {
yading@10:         uint8_t *U2 = U + s->pic->linesize[1];
yading@10:         uint8_t *V2 = V + s->pic->linesize[2];
yading@10: 
yading@10:         for (j = 0; j < avctx->height >> 2; j++) {
yading@10:             for (i = 0; i < avctx->width >> 1; i += 2) {
yading@10:                 if (src_end - src < 1)
yading@10:                     return 0;
yading@10:                 val = *src++;
yading@10:                 if (val) {
yading@10:                     if (val >= table_size)
yading@10:                         return AVERROR_INVALIDDATA;
yading@10:                     val  = AV_RL16(table + (val << 1));
yading@10:                     uval = (val >> 3) & 0xF8;
yading@10:                     vval = (val >> 8) & 0xF8;
yading@10:                     U[i] = U[i+1] = U2[i] = U2[i+1] = uval | (uval >> 5);
yading@10:                     V[i] = V[i+1] = V2[i] = V2[i+1] = vval | (vval >> 5);
yading@10:                 }
yading@10:             }
yading@10:             U  += s->pic->linesize[1] * 2;
yading@10:             V  += s->pic->linesize[2] * 2;
yading@10:             U2 += s->pic->linesize[1] * 2;
yading@10:             V2 += s->pic->linesize[2] * 2;
yading@10:         }
yading@10:         if (avctx->height & 3) {
yading@10:             int lines = ((avctx->height + 1) >> 1) - (avctx->height >> 2) * 2;
yading@10: 
yading@10:             memcpy(U, U - lines * s->pic->linesize[1], lines * s->pic->linesize[1]);
yading@10:             memcpy(V, V - lines * s->pic->linesize[2], lines * s->pic->linesize[2]);
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int xan_decode_frame_type0(AVCodecContext *avctx)
yading@10: {
yading@10:     XanContext *s = avctx->priv_data;
yading@10:     uint8_t *ybuf, *prev_buf, *src = s->scratch_buffer;
yading@10:     unsigned  chroma_off, corr_off;
yading@10:     int cur, last;
yading@10:     int i, j;
yading@10:     int ret;
yading@10: 
yading@10:     chroma_off = bytestream2_get_le32(&s->gb);
yading@10:     corr_off   = bytestream2_get_le32(&s->gb);
yading@10: 
yading@10:     if ((ret = xan_decode_chroma(avctx, chroma_off)) != 0)
yading@10:         return ret;
yading@10: 
yading@10:     if (corr_off >= bytestream2_size(&s->gb)) {
yading@10:         av_log(avctx, AV_LOG_WARNING, "Ignoring invalid correction block position\n");
yading@10:         corr_off = 0;
yading@10:     }
yading@10:     bytestream2_seek(&s->gb, 12, SEEK_SET);
yading@10:     ret = xan_unpack_luma(s, src, s->buffer_size >> 1);
yading@10:     if (ret) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
yading@10:         return ret;
yading@10:     }
yading@10: 
yading@10:     ybuf = s->y_buffer;
yading@10:     last = *src++;
yading@10:     ybuf[0] = last << 1;
yading@10:     for (j = 1; j < avctx->width - 1; j += 2) {
yading@10:         cur = (last + *src++) & 0x1F;
yading@10:         ybuf[j]   = last + cur;
yading@10:         ybuf[j+1] = cur << 1;
yading@10:         last = cur;
yading@10:     }
yading@10:     if(j < avctx->width)
yading@10:         ybuf[j]  = last << 1;
yading@10:     prev_buf = ybuf;
yading@10:     ybuf += avctx->width;
yading@10: 
yading@10:     for (i = 1; i < avctx->height; i++) {
yading@10:         last = ((prev_buf[0] >> 1) + *src++) & 0x1F;
yading@10:         ybuf[0] = last << 1;
yading@10:         for (j = 1; j < avctx->width - 1; j += 2) {
yading@10:             cur = ((prev_buf[j + 1] >> 1) + *src++) & 0x1F;
yading@10:             ybuf[j]   = last + cur;
yading@10:             ybuf[j+1] = cur << 1;
yading@10:             last = cur;
yading@10:         }
yading@10:         if(j < avctx->width)
yading@10:             ybuf[j] = last << 1;
yading@10:         prev_buf = ybuf;
yading@10:         ybuf += avctx->width;
yading@10:     }
yading@10: 
yading@10:     if (corr_off) {
yading@10:         int dec_size;
yading@10: 
yading@10:         bytestream2_seek(&s->gb, 8 + corr_off, SEEK_SET);
yading@10:         dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size / 2);
yading@10:         if (dec_size < 0)
yading@10:             dec_size = 0;
yading@10:         else
yading@10:             dec_size = FFMIN(dec_size, s->buffer_size/2 - 1);
yading@10: 
yading@10:         for (i = 0; i < dec_size; i++)
yading@10:             s->y_buffer[i*2+1] = (s->y_buffer[i*2+1] + (s->scratch_buffer[i] << 1)) & 0x3F;
yading@10:     }
yading@10: 
yading@10:     src  = s->y_buffer;
yading@10:     ybuf = s->pic->data[0];
yading@10:     for (j = 0; j < avctx->height; j++) {
yading@10:         for (i = 0; i < avctx->width; i++)
yading@10:             ybuf[i] = (src[i] << 2) | (src[i] >> 3);
yading@10:         src  += avctx->width;
yading@10:         ybuf += s->pic->linesize[0];
yading@10:     }
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int xan_decode_frame_type1(AVCodecContext *avctx)
yading@10: {
yading@10:     XanContext *s = avctx->priv_data;
yading@10:     uint8_t *ybuf, *src = s->scratch_buffer;
yading@10:     int cur, last;
yading@10:     int i, j;
yading@10:     int ret;
yading@10: 
yading@10:     if ((ret = xan_decode_chroma(avctx, bytestream2_get_le32(&s->gb))) != 0)
yading@10:         return ret;
yading@10: 
yading@10:     bytestream2_seek(&s->gb, 16, SEEK_SET);
yading@10:     ret = xan_unpack_luma(s, src,
yading@10:                           s->buffer_size >> 1);
yading@10:     if (ret) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
yading@10:         return ret;
yading@10:     }
yading@10: 
yading@10:     ybuf = s->y_buffer;
yading@10:     for (i = 0; i < avctx->height; i++) {
yading@10:         last = (ybuf[0] + (*src++ << 1)) & 0x3F;
yading@10:         ybuf[0] = last;
yading@10:         for (j = 1; j < avctx->width - 1; j += 2) {
yading@10:             cur = (ybuf[j + 1] + (*src++ << 1)) & 0x3F;
yading@10:             ybuf[j]   = (last + cur) >> 1;
yading@10:             ybuf[j+1] = cur;
yading@10:             last = cur;
yading@10:         }
yading@10:         if(j < avctx->width)
yading@10:             ybuf[j] = last;
yading@10:         ybuf += avctx->width;
yading@10:     }
yading@10: 
yading@10:     src = s->y_buffer;
yading@10:     ybuf = s->pic->data[0];
yading@10:     for (j = 0; j < avctx->height; j++) {
yading@10:         for (i = 0; i < avctx->width; i++)
yading@10:             ybuf[i] = (src[i] << 2) | (src[i] >> 3);
yading@10:         src  += avctx->width;
yading@10:         ybuf += s->pic->linesize[0];
yading@10:     }
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int xan_decode_frame(AVCodecContext *avctx,
yading@10:                             void *data, int *got_frame,
yading@10:                             AVPacket *avpkt)
yading@10: {
yading@10:     XanContext *s = avctx->priv_data;
yading@10:     int ftype;
yading@10:     int ret;
yading@10: 
yading@10:     if ((ret = ff_reget_buffer(avctx, s->pic)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     bytestream2_init(&s->gb, avpkt->data, avpkt->size);
yading@10:     ftype = bytestream2_get_le32(&s->gb);
yading@10:     switch (ftype) {
yading@10:     case 0:
yading@10:         ret = xan_decode_frame_type0(avctx);
yading@10:         break;
yading@10:     case 1:
yading@10:         ret = xan_decode_frame_type1(avctx);
yading@10:         break;
yading@10:     default:
yading@10:         av_log(avctx, AV_LOG_ERROR, "Unknown frame type %d\n", ftype);
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10:     if (ret)
yading@10:         return ret;
yading@10: 
yading@10:     if ((ret = av_frame_ref(data, s->pic)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     *got_frame = 1;
yading@10: 
yading@10:     return avpkt->size;
yading@10: }
yading@10: 
yading@10: static av_cold int xan_decode_end(AVCodecContext *avctx)
yading@10: {
yading@10:     XanContext *s = avctx->priv_data;
yading@10: 
yading@10:     av_frame_free(&s->pic);
yading@10: 
yading@10:     av_freep(&s->y_buffer);
yading@10:     av_freep(&s->scratch_buffer);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: AVCodec ff_xan_wc4_decoder = {
yading@10:     .name           = "xan_wc4",
yading@10:     .type           = AVMEDIA_TYPE_VIDEO,
yading@10:     .id             = AV_CODEC_ID_XAN_WC4,
yading@10:     .priv_data_size = sizeof(XanContext),
yading@10:     .init           = xan_decode_init,
yading@10:     .close          = xan_decode_end,
yading@10:     .decode         = xan_decode_frame,
yading@10:     .capabilities   = CODEC_CAP_DR1,
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("Wing Commander IV / Xxan"),
yading@10: };