libavcodec/sgirledec.c

   1 /*
   2  * Silicon Graphics RLE 8-bit video decoder
   3  * Copyright (c) 2012 Peter Ross
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file
  24  * Silicon Graphics RLE 8-bit video decoder
  25  * @note Data is packed in rbg323 with rle, contained in mv or mov.
  26  * The algorithm and pixfmt are subtly different from SGI images.
  27  */
  28
  29 #include "libavutil/common.h"
  30
  31 #include "avcodec.h"
  32 #include "codec_internal.h"
  33 #include "decode.h"
  34
  35 static av_cold int sgirle_decode_init(AVCodecContext *avctx)
  36 {
  37     avctx->pix_fmt = AV_PIX_FMT_BGR8;
  38     return 0;
  39 }
  40
  41 /**
  42  * Convert SGI RBG323 pixel into AV_PIX_FMT_BGR8
  43  * SGI RGB data is packed as 8bpp, (msb)3R 2B 3G(lsb)
  44  */
  45 #define RBG323_TO_BGR8(x) ((((x) << 3) & 0xC0) |                                \
  46                            (((x) << 3) & 0x38) |                                \
  47                            (((x) >> 5) & 7))
  48 static av_always_inline
  49 void rbg323_to_bgr8(uint8_t *dst, const uint8_t *src, int size)
  50 {
  51     int i;
  52     for (i = 0; i < size; i++)
  53         dst[i] = RBG323_TO_BGR8(src[i]);
  54 }
  55
  56 /**
  57  * @param[out] dst Destination buffer
  58  * @param[in] src  Source buffer
  59  * @param src_size Source buffer size (bytes)
  60  * @param width    Width of destination buffer (pixels)
  61  * @param height   Height of destination buffer (pixels)
  62  * @param linesize Line size of destination buffer (bytes)
  63  *
  64  * @return <0 on error
  65  */
  66 static int decode_sgirle8(AVCodecContext *avctx, uint8_t *dst,
  67                           const uint8_t *src, int src_size,
  68                           int width, int height, ptrdiff_t linesize)
  69 {
  70     const uint8_t *src_end = src + src_size;
  71     int x = 0, y = 0;
  72
  73 #define INC_XY(n)                                                             \
  74     x += n;                                                                   \
  75     if (x >= width) {                                                         \
  76         y++;                                                                  \
  77         if (y >= height)                                                      \
  78             return 0;                                                         \
  79         x = 0;                                                                \
  80     }
  81
  82     while (src_end - src >= 2) {
  83         uint8_t v = *src++;
  84         if (v > 0 && v < 0xC0) {
  85             do {
  86                 int length = FFMIN(v, width - x);
  87                 if (length <= 0)
  88                     break;
  89                 memset(dst + y * linesize + x, RBG323_TO_BGR8(*src), length);
  90                 INC_XY(length);
  91                 v -= length;
  92             } while (v > 0);
  93             src++;
  94         } else if (v >= 0xC1) {
  95             v -= 0xC0;
  96             do {
  97                 int length = FFMIN3(v, width - x, src_end - src);
  98                 if (src_end - src < length || length <= 0)
  99                     break;
 100                 rbg323_to_bgr8(dst + y * linesize + x, src, length);
 101                 INC_XY(length);
 102                 src += length;
 103                 v   -= length;
 104             } while (v > 0);
 105         } else {
 106             avpriv_request_sample(avctx, "opcode %d", v);
 107             return AVERROR_PATCHWELCOME;
 108         }
 109     }
 110     return 0;
 111 }
 112
 113 static int sgirle_decode_frame(AVCodecContext *avctx, AVFrame *frame,
 114                                int *got_frame, AVPacket *avpkt)
 115 {
 116     int ret;
 117
 118     if (avpkt->size * 192ll / 2 < avctx->width * avctx->height)
 119         return AVERROR_INVALIDDATA;
 120
 121     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
 122         return ret;
 123
 124     ret = decode_sgirle8(avctx, frame->data[0], avpkt->data, avpkt->size,
 125                          avctx->width, avctx->height, frame->linesize[0]);
 126     if (ret < 0)
 127         return ret;
 128
 129     *got_frame = 1;
 130
 131     return avpkt->size;
 132 }
 133
 134 const FFCodec ff_sgirle_decoder = {
 135     .p.name         = "sgirle",
 136     CODEC_LONG_NAME("Silicon Graphics RLE 8-bit video"),
 137     .p.type         = AVMEDIA_TYPE_VIDEO,
 138     .p.id           = AV_CODEC_ID_SGIRLE,
 139     .init           = sgirle_decode_init,
 140     FF_CODEC_DECODE_CB(sgirle_decode_frame),
 141     .p.capabilities = AV_CODEC_CAP_DR1,
 142 };