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libavcodec/targaenc.c

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00001 /*
00002  * Targa (.tga) image encoder
00003  * Copyright (c) 2007 Bobby Bingham
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include "libavutil/intreadwrite.h"
00023 #include "avcodec.h"
00024 #include "rle.h"
00025 
00026 typedef struct TargaContext {
00027     AVFrame picture;
00028 } TargaContext;
00029 
00040 static int targa_encode_rle(uint8_t *outbuf, int out_size, AVFrame *pic,
00041                             int bpp, int w, int h)
00042 {
00043     int y,ret;
00044     uint8_t *out;
00045 
00046     out = outbuf;
00047 
00048     for(y = 0; y < h; y ++) {
00049         ret = ff_rle_encode(out, out_size, pic->data[0] + pic->linesize[0] * y, bpp, w, 0x7f, 0, -1, 0);
00050         if(ret == -1){
00051             return -1;
00052         }
00053         out+= ret;
00054         out_size -= ret;
00055     }
00056 
00057     return out - outbuf;
00058 }
00059 
00060 static int targa_encode_normal(uint8_t *outbuf, AVFrame *pic, int bpp, int w, int h)
00061 {
00062     int i, n = bpp * w;
00063     uint8_t *out = outbuf;
00064     uint8_t *ptr = pic->data[0];
00065 
00066     for(i=0; i < h; i++) {
00067         memcpy(out, ptr, n);
00068         out += n;
00069         ptr += pic->linesize[0];
00070     }
00071 
00072     return out - outbuf;
00073 }
00074 
00075 static int targa_encode_frame(AVCodecContext *avctx,
00076                               unsigned char *outbuf,
00077                               int buf_size, void *data){
00078     AVFrame *p = data;
00079     int bpp, picsize, datasize = -1;
00080     uint8_t *out;
00081 
00082     if(avctx->width > 0xffff || avctx->height > 0xffff) {
00083         av_log(avctx, AV_LOG_ERROR, "image dimensions too large\n");
00084         return -1;
00085     }
00086     picsize = avpicture_get_size(avctx->pix_fmt, avctx->width, avctx->height);
00087     if(buf_size < picsize + 45) {
00088         av_log(avctx, AV_LOG_ERROR, "encoded frame too large\n");
00089         return -1;
00090     }
00091 
00092     p->pict_type= FF_I_TYPE;
00093     p->key_frame= 1;
00094 
00095     /* zero out the header and only set applicable fields */
00096     memset(outbuf, 0, 12);
00097     AV_WL16(outbuf+12, avctx->width);
00098     AV_WL16(outbuf+14, avctx->height);
00099     outbuf[17] = 0x20;           /* origin is top-left. no alpha */
00100 
00101     /* TODO: support alpha channel */
00102     switch(avctx->pix_fmt) {
00103     case PIX_FMT_GRAY8:
00104         outbuf[2] = 3;           /* uncompressed grayscale image */
00105         outbuf[16] = 8;          /* bpp */
00106         break;
00107     case PIX_FMT_RGB555LE:
00108         outbuf[2] = 2;           /* uncompresses true-color image */
00109         outbuf[16] = 16;         /* bpp */
00110         break;
00111     case PIX_FMT_BGR24:
00112         outbuf[2] = 2;           /* uncompressed true-color image */
00113         outbuf[16] = 24;         /* bpp */
00114         break;
00115     default:
00116         return -1;
00117     }
00118     bpp = outbuf[16] >> 3;
00119 
00120     out = outbuf + 18;  /* skip past the header we just output */
00121 
00122     /* try RLE compression */
00123     if (avctx->coder_type != FF_CODER_TYPE_RAW)
00124         datasize = targa_encode_rle(out, picsize, p, bpp, avctx->width, avctx->height);
00125 
00126     /* if that worked well, mark the picture as RLE compressed */
00127     if(datasize >= 0)
00128         outbuf[2] |= 8;
00129 
00130     /* if RLE didn't make it smaller, go back to no compression */
00131     else datasize = targa_encode_normal(out, p, bpp, avctx->width, avctx->height);
00132 
00133     out += datasize;
00134 
00135     /* The standard recommends including this section, even if we don't use
00136      * any of the features it affords. TODO: take advantage of the pixel
00137      * aspect ratio and encoder ID fields available? */
00138     memcpy(out, "\0\0\0\0\0\0\0\0TRUEVISION-XFILE.", 26);
00139 
00140     return out + 26 - outbuf;
00141 }
00142 
00143 static av_cold int targa_encode_init(AVCodecContext *avctx)
00144 {
00145     TargaContext *s = avctx->priv_data;
00146 
00147     avcodec_get_frame_defaults(&s->picture);
00148     s->picture.key_frame= 1;
00149     avctx->coded_frame= &s->picture;
00150 
00151     return 0;
00152 }
00153 
00154 AVCodec targa_encoder = {
00155     .name = "targa",
00156     .type = AVMEDIA_TYPE_VIDEO,
00157     .id = CODEC_ID_TARGA,
00158     .priv_data_size = sizeof(TargaContext),
00159     .init = targa_encode_init,
00160     .encode = targa_encode_frame,
00161     .pix_fmts= (const enum PixelFormat[]){PIX_FMT_BGR24, PIX_FMT_RGB555LE, PIX_FMT_GRAY8, PIX_FMT_NONE},
00162     .long_name= NULL_IF_CONFIG_SMALL("Truevision Targa image"),
00163 };

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