libavcodec/targaenc.c

   1 /*
   2  * Targa (.tga) image encoder
   3  * Copyright (c) 2007 Bobby Bingham
   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 #include "avcodec.h"
  22 #include "rle.h"
  23
  24 typedef struct TargaContext {
  25     AVFrame picture;
  26 } TargaContext;
  27
  28 /**
  29  * RLE compress the image, with maximum size of out_size
  30  * @param outbuf Output buffer
  31  * @param out_size Maximum output size
  32  * @param pic Image to compress
  33  * @param bpp Bytes per pixel
  34  * @param w Image width
  35  * @param h Image height
  36  * @return Size of output in bytes, or -1 if larger than out_size
  37  */
  38 static int targa_encode_rle(uint8_t *outbuf, int out_size, AVFrame *pic,
  39                             int bpp, int w, int h)
  40 {
  41     int y,ret;
  42     uint8_t *out;
  43
  44     out = outbuf;
  45
  46     for(y = 0; y < h; y ++) {
  47         ret = ff_rle_encode(out, out_size, pic->data[0] + pic->linesize[0] * y, bpp, w, 0x7f, 0, -1, 0);
  48         if(ret == -1){
  49             return -1;
  50         }
  51         out+= ret;
  52         out_size -= ret;
  53     }
  54
  55     return out - outbuf;
  56 }
  57
  58 static int targa_encode_normal(uint8_t *outbuf, AVFrame *pic, int bpp, int w, int h)
  59 {
  60     int i, n = bpp * w;
  61     uint8_t *out = outbuf;
  62     uint8_t *ptr = pic->data[0];
  63
  64     for(i=0; i < h; i++) {
  65         memcpy(out, ptr, n);
  66         out += n;
  67         ptr += pic->linesize[0];
  68     }
  69
  70     return out - outbuf;
  71 }
  72
  73 static int targa_encode_frame(AVCodecContext *avctx,
  74                               unsigned char *outbuf,
  75                               int buf_size, void *data){
  76     AVFrame *p = data;
  77     int bpp, picsize, datasize;
  78     uint8_t *out;
  79
  80     if(avctx->width > 0xffff || avctx->height > 0xffff) {
  81         av_log(avctx, AV_LOG_ERROR, "image dimensions too large\n");
  82         return -1;
  83     }
  84     picsize = avpicture_get_size(avctx->pix_fmt, avctx->width, avctx->height);
  85     if(buf_size < picsize + 45) {
  86         av_log(avctx, AV_LOG_ERROR, "encoded frame too large\n");
  87         return -1;
  88     }
  89
  90     p->pict_type= FF_I_TYPE;
  91     p->key_frame= 1;
  92
  93     /* zero out the header and only set applicable fields */
  94     memset(outbuf, 0, 12);
  95     AV_WL16(outbuf+12, avctx->width);
  96     AV_WL16(outbuf+14, avctx->height);
  97     outbuf[17] = 0x20;           /* origin is top-left. no alpha */
  98
  99     /* TODO: support alpha channel */
 100     switch(avctx->pix_fmt) {
 101     case PIX_FMT_GRAY8:
 102         outbuf[2] = 3;           /* uncompressed grayscale image */
 103         outbuf[16] = 8;          /* bpp */
 104         break;
 105     case PIX_FMT_RGB555:
 106         outbuf[2] = 2;           /* uncompresses true-color image */
 107         outbuf[16] = 16;         /* bpp */
 108         break;
 109     case PIX_FMT_BGR24:
 110         outbuf[2] = 2;           /* uncompressed true-color image */
 111         outbuf[16] = 24;         /* bpp */
 112         break;
 113     default:
 114         return -1;
 115     }
 116     bpp = outbuf[16] >> 3;
 117
 118     out = outbuf + 18;  /* skip past the header we just output */
 119
 120     /* try RLE compression */
 121     datasize = targa_encode_rle(out, picsize, p, bpp, avctx->width, avctx->height);
 122
 123     /* if that worked well, mark the picture as RLE compressed */
 124     if(datasize >= 0)
 125         outbuf[2] |= 8;
 126
 127     /* if RLE didn't make it smaller, go back to no compression */
 128     else datasize = targa_encode_normal(out, p, bpp, avctx->width, avctx->height);
 129
 130     out += datasize;
 131
 132     /* The standard recommends including this section, even if we don't use
 133      * any of the features it affords. TODO: take advantage of the pixel
 134      * aspect ratio and encoder ID fields available? */
 135     memcpy(out, "\0\0\0\0\0\0\0\0TRUEVISION-XFILE.", 26);
 136
 137     return out + 26 - outbuf;
 138 }
 139
 140 static av_cold int targa_encode_init(AVCodecContext *avctx)
 141 {
 142     TargaContext *s = avctx->priv_data;
 143
 144     avcodec_get_frame_defaults(&s->picture);
 145     s->picture.key_frame= 1;
 146     avctx->coded_frame= &s->picture;
 147
 148     return 0;
 149 }
 150
 151 AVCodec targa_encoder = {
 152     .name = "targa",
 153     .type = CODEC_TYPE_VIDEO,
 154     .id = CODEC_ID_TARGA,
 155     .priv_data_size = sizeof(TargaContext),
 156     .init = targa_encode_init,
 157     .encode = targa_encode_frame,
 158     .pix_fmts= (enum PixelFormat[]){PIX_FMT_BGR24, PIX_FMT_RGB555, PIX_FMT_GRAY8, PIX_FMT_NONE},
 159     .long_name= NULL_IF_CONFIG_SMALL("Truevision Targa image"),
 160 };