libavcodec/pcxenc.c
Go to the documentation of this file.
00001 /*
00002  * PC Paintbrush PCX (.pcx) image encoder
00003  * Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>
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 
00029 #include "avcodec.h"
00030 #include "bytestream.h"
00031 #include "libavutil/imgutils.h"
00032 
00033 typedef struct PCXContext {
00034     AVFrame picture;
00035 } PCXContext;
00036 
00037 static const uint32_t monoblack_pal[16] = { 0x000000, 0xFFFFFF };
00038 
00039 static av_cold int pcx_encode_init(AVCodecContext *avctx)
00040 {
00041     PCXContext *s = avctx->priv_data;
00042 
00043     avcodec_get_frame_defaults(&s->picture);
00044     avctx->coded_frame = &s->picture;
00045 
00046     return 0;
00047 }
00048 
00059 static int pcx_rle_encode(      uint8_t *dst, int dst_size,
00060                           const uint8_t *src, int src_plane_size, int nplanes)
00061 {
00062     int p;
00063     const uint8_t *dst_start = dst;
00064 
00065     // check worst-case upper bound on dst_size
00066     if (dst_size < 2LL * src_plane_size * nplanes || src_plane_size <= 0)
00067         return -1;
00068 
00069     for (p = 0; p < nplanes; p++) {
00070         int count = 1;
00071         const uint8_t *src_plane = src + p;
00072         const uint8_t *src_plane_end = src_plane + src_plane_size * nplanes;
00073         uint8_t prev = *src_plane;
00074         src_plane += nplanes;
00075 
00076         for (; ; src_plane += nplanes) {
00077             if (src_plane < src_plane_end && *src_plane == prev && count < 0x3F) {
00078                 // current byte is same as prev
00079                 ++count;
00080             } else {
00081                 // output prev * count
00082                 if (count != 1 || prev >= 0xC0)
00083                     *dst++ = 0xC0 | count;
00084                 *dst++ = prev;
00085 
00086                 if (src_plane == src_plane_end)
00087                     break;
00088 
00089                 // start new run
00090                 count = 1;
00091                 prev = *src_plane;
00092             }
00093         }
00094     }
00095 
00096     return dst - dst_start;
00097 }
00098 
00099 static int pcx_encode_frame(AVCodecContext *avctx,
00100                             unsigned char *buf, int buf_size, void *data)
00101 {
00102     PCXContext *s = avctx->priv_data;
00103     AVFrame *const pict = &s->picture;
00104     const uint8_t *buf_start = buf;
00105     const uint8_t *buf_end   = buf + buf_size;
00106 
00107     int bpp, nplanes, i, y, line_bytes, written;
00108     const uint32_t *pal = NULL;
00109     uint32_t palette256[256];
00110     const uint8_t *src;
00111 
00112     *pict = *(AVFrame *)data;
00113     pict->pict_type = AV_PICTURE_TYPE_I;
00114     pict->key_frame = 1;
00115 
00116     if (avctx->width > 65535 || avctx->height > 65535) {
00117         av_log(avctx, AV_LOG_ERROR, "image dimensions do not fit in 16 bits\n");
00118         return -1;
00119     }
00120 
00121     switch (avctx->pix_fmt) {
00122     case PIX_FMT_RGB24:
00123         bpp = 8;
00124         nplanes = 3;
00125         break;
00126     case PIX_FMT_RGB8:
00127     case PIX_FMT_BGR8:
00128     case PIX_FMT_RGB4_BYTE:
00129     case PIX_FMT_BGR4_BYTE:
00130     case PIX_FMT_GRAY8:
00131         bpp = 8;
00132         nplanes = 1;
00133         ff_set_systematic_pal2(palette256, avctx->pix_fmt);
00134         pal = palette256;
00135         break;
00136     case PIX_FMT_PAL8:
00137         bpp = 8;
00138         nplanes = 1;
00139         pal = (uint32_t *)pict->data[1];
00140         break;
00141     case PIX_FMT_MONOBLACK:
00142         bpp = 1;
00143         nplanes = 1;
00144         pal = monoblack_pal;
00145         break;
00146     default:
00147         av_log(avctx, AV_LOG_ERROR, "unsupported pixfmt\n");
00148         return -1;
00149     }
00150 
00151     line_bytes = (avctx->width * bpp + 7) >> 3;
00152     line_bytes = (line_bytes + 1) & ~1;
00153 
00154     bytestream_put_byte(&buf, 10);                  // manufacturer
00155     bytestream_put_byte(&buf, 5);                   // version
00156     bytestream_put_byte(&buf, 1);                   // encoding
00157     bytestream_put_byte(&buf, bpp);                 // bits per pixel per plane
00158     bytestream_put_le16(&buf, 0);                   // x min
00159     bytestream_put_le16(&buf, 0);                   // y min
00160     bytestream_put_le16(&buf, avctx->width - 1);    // x max
00161     bytestream_put_le16(&buf, avctx->height - 1);   // y max
00162     bytestream_put_le16(&buf, 0);                   // horizontal DPI
00163     bytestream_put_le16(&buf, 0);                   // vertical DPI
00164     for (i = 0; i < 16; i++)
00165         bytestream_put_be24(&buf, pal ? pal[i] : 0);// palette (<= 16 color only)
00166     bytestream_put_byte(&buf, 0);                   // reserved
00167     bytestream_put_byte(&buf, nplanes);             // number of planes
00168     bytestream_put_le16(&buf, line_bytes);          // scanline plane size in bytes
00169 
00170     while (buf - buf_start < 128)
00171         *buf++= 0;
00172 
00173     src = pict->data[0];
00174 
00175     for (y = 0; y < avctx->height; y++) {
00176         if ((written = pcx_rle_encode(buf, buf_end - buf,
00177                                       src, line_bytes, nplanes)) < 0) {
00178             av_log(avctx, AV_LOG_ERROR, "buffer too small\n");
00179             return -1;
00180         }
00181         buf += written;
00182         src += pict->linesize[0];
00183     }
00184 
00185     if (nplanes == 1 && bpp == 8) {
00186         if (buf_end - buf < 257) {
00187             av_log(avctx, AV_LOG_ERROR, "buffer too small\n");
00188             return -1;
00189         }
00190         bytestream_put_byte(&buf, 12);
00191         for (i = 0; i < 256; i++) {
00192             bytestream_put_be24(&buf, pal[i]);
00193         }
00194     }
00195 
00196     return buf - buf_start;
00197 }
00198 
00199 AVCodec ff_pcx_encoder = {
00200     .name           = "pcx",
00201     .type           = AVMEDIA_TYPE_VIDEO,
00202     .id             = CODEC_ID_PCX,
00203     .priv_data_size = sizeof(PCXContext),
00204     .init           = pcx_encode_init,
00205     .encode         = pcx_encode_frame,
00206     .pix_fmts = (const enum PixelFormat[]){
00207         PIX_FMT_RGB24,
00208         PIX_FMT_RGB8, PIX_FMT_BGR8, PIX_FMT_RGB4_BYTE, PIX_FMT_BGR4_BYTE, PIX_FMT_GRAY8, PIX_FMT_PAL8,
00209         PIX_FMT_MONOBLACK,
00210         PIX_FMT_NONE},
00211     .long_name = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),
00212 };