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