ffmpeg/libavcodec/aliaspixenc.c

   1 /*
   2  * Alias PIX image encoder
   3  * Copyright (C) 2014 Vittorio Giovara <vittorio.giovara@gmail.com>
   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
  24 #include "avcodec.h"
  25 #include "bytestream.h"
  26 #include "internal.h"
  27
  28 #define ALIAS_HEADER_SIZE 10
  29
  30 static av_cold int encode_init(AVCodecContext *avctx)
  31 {
  32     avctx->coded_frame = av_frame_alloc();
  33     if (!avctx->coded_frame)
  34         return AVERROR(ENOMEM);
  35     return 0;
  36 }
  37
  38 static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
  39                         const AVFrame *frame, int *got_packet)
  40 {
  41     int width, height, bits_pixel, i, j, length, ret;
  42     uint8_t *in_buf, *buf;
  43
  44     avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;
  45     avctx->coded_frame->key_frame = 1;
  46
  47     width  = avctx->width;
  48     height = avctx->height;
  49
  50     if (width > 65535 || height > 65535 ||
  51         width * height >= INT_MAX / 4 - ALIAS_HEADER_SIZE) {
  52         av_log(avctx, AV_LOG_ERROR, "Invalid image size %dx%d.\n", width, height);
  53         return AVERROR_INVALIDDATA;
  54     }
  55
  56     switch (avctx->pix_fmt) {
  57     case AV_PIX_FMT_GRAY8:
  58         bits_pixel = 8;
  59         break;
  60     case AV_PIX_FMT_BGR24:
  61         bits_pixel = 24;
  62         break;
  63     default:
  64         return AVERROR(EINVAL);
  65     }
  66
  67     length = ALIAS_HEADER_SIZE + 4 * width * height; // max possible
  68     if ((ret = ff_alloc_packet(pkt, length)) < 0) {
  69         av_log(avctx, AV_LOG_ERROR, "Error getting output packet of size %d.\n", length);
  70         return ret;
  71     }
  72
  73     buf = pkt->data;
  74
  75     /* Encode header. */
  76     bytestream_put_be16(&buf, width);
  77     bytestream_put_be16(&buf, height);
  78     bytestream_put_be32(&buf, 0); /* X, Y offset */
  79     bytestream_put_be16(&buf, bits_pixel);
  80
  81     for (j = 0; j < height; j++) {
  82         in_buf = frame->data[0] + frame->linesize[0] * j;
  83         for (i = 0; i < width; ) {
  84             int count = 0;
  85             int pixel;
  86
  87             if (avctx->pix_fmt == AV_PIX_FMT_GRAY8) {
  88                 pixel = *in_buf;
  89                 while (count < 255 && count + i < width && pixel == *in_buf) {
  90                     count++;
  91                     in_buf++;
  92                 }
  93                 bytestream_put_byte(&buf, count);
  94                 bytestream_put_byte(&buf, pixel);
  95             } else { /* AV_PIX_FMT_BGR24 */
  96                 pixel = AV_RB24(in_buf);
  97                 while (count < 255 && count + i < width &&
  98                        pixel == AV_RB24(in_buf)) {
  99                     count++;
 100                     in_buf += 3;
 101                 }
 102                 bytestream_put_byte(&buf, count);
 103                 bytestream_put_be24(&buf, pixel);
 104             }
 105             i += count;
 106         }
 107     }
 108
 109     /* Total length */
 110     av_shrink_packet(pkt, buf - pkt->data);
 111     pkt->flags |= AV_PKT_FLAG_KEY;
 112     *got_packet = 1;
 113
 114     return 0;
 115 }
 116
 117 static av_cold int encode_close(AVCodecContext *avctx)
 118 {
 119     av_frame_free(&avctx->coded_frame);
 120     return 0;
 121 }
 122
 123 AVCodec ff_alias_pix_encoder = {
 124     .name      = "alias_pix",
 125     .long_name = NULL_IF_CONFIG_SMALL("Alias/Wavefront PIX image"),
 126     .type      = AVMEDIA_TYPE_VIDEO,
 127     .id        = AV_CODEC_ID_ALIAS_PIX,
 128     .init      = encode_init,
 129     .encode2   = encode_frame,
 130     .close     = encode_close,
 131     .pix_fmts  = (const enum AVPixelFormat[]) {
 132         AV_PIX_FMT_BGR24, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE
 133     },
 134 };