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
  22 #include "libavutil/intreadwrite.h"
  23 #include "avcodec.h"
  24 #include "rle.h"
  25
  26 typedef struct TargaContext {
  27     AVFrame picture;
  28 } TargaContext;
  29
  30 /**
  31  * RLE compress the image, with maximum size of out_size
  32  * @param outbuf Output buffer
  33  * @param out_size Maximum output size
  34  * @param pic Image to compress
  35  * @param bpp Bytes per pixel
  36  * @param w Image width
  37  * @param h Image height
  38  * @return Size of output in bytes, or -1 if larger than out_size
  39  */
  40 static int targa_encode_rle(uint8_t *outbuf, int out_size, AVFrame *pic,
  41                             int bpp, int w, int h)
  42 {
  43     int y,ret;
  44     uint8_t *out;
  45
  46     out = outbuf;
  47
  48     for(y = 0; y < h; y ++) {
  49         ret = ff_rle_encode(out, out_size, pic->data[0] + pic->linesize[0] * y, bpp, w, 0x7f, 0, -1, 0);
  50         if(ret == -1){
  51             return -1;
  52         }
  53         out+= ret;
  54         out_size -= ret;
  55     }
  56
  57     return out - outbuf;
  58 }
  59
  60 static int targa_encode_normal(uint8_t *outbuf, AVFrame *pic, int bpp, int w, int h)
  61 {
  62     int i, n = bpp * w;
  63     uint8_t *out = outbuf;
  64     uint8_t *ptr = pic->data[0];
  65
  66     for(i=0; i < h; i++) {
  67         memcpy(out, ptr, n);
  68         out += n;
  69         ptr += pic->linesize[0];
  70     }
  71
  72     return out - outbuf;
  73 }
  74
  75 static int targa_encode_frame(AVCodecContext *avctx,
  76                               unsigned char *outbuf,
  77                               int buf_size, void *data){
  78     AVFrame *p = data;
  79     int bpp, picsize, datasize;
  80     uint8_t *out;
  81
  82     if(avctx->width > 0xffff || avctx->height > 0xffff) {
  83         av_log(avctx, AV_LOG_ERROR, "image dimensions too large\n");
  84         return -1;
  85     }
  86     picsize = avpicture_get_size(avctx->pix_fmt, avctx->width, avctx->height);
  87     if(buf_size < picsize + 45) {
  88         av_log(avctx, AV_LOG_ERROR, "encoded frame too large\n");
  89         return -1;
  90     }
  91
  92     p->pict_type= FF_I_TYPE;
  93     p->key_frame= 1;
  94
  95     /* zero out the header and only set applicable fields */
  96     memset(outbuf, 0, 12);
  97     AV_WL16(outbuf+12, avctx->width);
  98     AV_WL16(outbuf+14, avctx->height);
  99     outbuf[17] = 0x20;           /* origin is top-left. no alpha */
 100
 101     /* TODO: support alpha channel */
 102     switch(avctx->pix_fmt) {
 103     case PIX_FMT_GRAY8:
 104         outbuf[2] = 3;           /* uncompressed grayscale image */
 105         outbuf[16] = 8;          /* bpp */
 106         break;
 107     case PIX_FMT_RGB555:
 108         outbuf[2] = 2;           /* uncompresses true-color image */
 109         outbuf[16] = 16;         /* bpp */
 110         break;
 111     case PIX_FMT_BGR24:
 112         outbuf[2] = 2;           /* uncompressed true-color image */
 113         outbuf[16] = 24;         /* bpp */
 114         break;
 115     default:
 116         return -1;
 117     }
 118     bpp = outbuf[16] >> 3;
 119
 120     out = outbuf + 18;  /* skip past the header we just output */
 121
 122     /* try RLE compression */
 123     datasize = targa_encode_rle(out, picsize, p, bpp, avctx->width, avctx->height);
 124
 125     /* if that worked well, mark the picture as RLE compressed */
 126     if(datasize >= 0)
 127         outbuf[2] |= 8;
 128
 129     /* if RLE didn't make it smaller, go back to no compression */
 130     else datasize = targa_encode_normal(out, p, bpp, avctx->width, avctx->height);
 131
 132     out += datasize;
 133
 134     /* The standard recommends including this section, even if we don't use
 135      * any of the features it affords. TODO: take advantage of the pixel
 136      * aspect ratio and encoder ID fields available? */
 137     memcpy(out, "\0\0\0\0\0\0\0\0TRUEVISION-XFILE.", 26);
 138
 139     return out + 26 - outbuf;
 140 }
 141
 142 static av_cold int targa_encode_init(AVCodecContext *avctx)
 143 {
 144     TargaContext *s = avctx->priv_data;
 145
 146     avcodec_get_frame_defaults(&s->picture);
 147     s->picture.key_frame= 1;
 148     avctx->coded_frame= &s->picture;
 149
 150     return 0;
 151 }
 152
 153 AVCodec targa_encoder = {
 154     .name = "targa",
 155     .type = CODEC_TYPE_VIDEO,
 156     .id = CODEC_ID_TARGA,
 157     .priv_data_size = sizeof(TargaContext),
 158     .init = targa_encode_init,
 159     .encode = targa_encode_frame,
 160     .pix_fmts= (enum PixelFormat[]){PIX_FMT_BGR24, PIX_FMT_RGB555, PIX_FMT_GRAY8, PIX_FMT_NONE},
 161     .long_name= NULL_IF_CONFIG_SMALL("Truevision Targa image"),
 162 };