libavcodec/hdrenc.c

   1 /*
   2  * Radiance HDR image format
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include "libavutil/mem.h"
  22 #include "avcodec.h"
  23 #include "bytestream.h"
  24 #include "codec_internal.h"
  25 #include "encode.h"
  26
  27 typedef struct HDREncContext {
  28     uint8_t *scanline;
  29 } HDREncContext;
  30
  31 static av_cold int hdr_encode_init(AVCodecContext *avctx)
  32 {
  33     HDREncContext *s = avctx->priv_data;
  34
  35     s->scanline = av_calloc(avctx->width * 4, sizeof(*s->scanline));
  36     if (!s->scanline)
  37         return AVERROR(ENOMEM);
  38
  39     return 0;
  40 }
  41
  42 static av_cold int hdr_encode_close(AVCodecContext *avctx)
  43 {
  44     HDREncContext *s = avctx->priv_data;
  45
  46     av_freep(&s->scanline);
  47
  48     return 0;
  49 }
  50
  51 static void bytestream_put_str(uint8_t **buf, const char *const line)
  52 {
  53     bytestream_put_buffer(buf, line, strlen(line));
  54 }
  55
  56 static void float2rgbe(uint8_t *rgbe, float red, float green, float blue)
  57 {
  58     float v;
  59     int e;
  60
  61     v = FFMAX3(red, green, blue);
  62
  63     if (v < 1e-32f) {
  64         rgbe[0] = rgbe[1] = rgbe[2] = rgbe[3] = 0;
  65     } else {
  66         v = frexpf(v, &e) * 256.f / v;
  67
  68         rgbe[0] = av_clip_uint8(red * v);
  69         rgbe[1] = av_clip_uint8(green * v);
  70         rgbe[2] = av_clip_uint8(blue * v);
  71         rgbe[3] = av_clip_uint8(e + 128);
  72     }
  73 }
  74
  75 static void rle(uint8_t **buffer, const uint8_t *data, int width)
  76 {
  77 #define MIN_RLE 4
  78     int cur = 0;
  79
  80     while (cur < width) {
  81         int run_count = 0, old_run_count = 0;
  82         int beg_run = cur;
  83         uint8_t buf[2];
  84
  85         while (run_count < MIN_RLE && beg_run < width) {
  86             beg_run += run_count;
  87             old_run_count = run_count;
  88             run_count = 1;
  89             while ((beg_run + run_count < width) && (run_count < 127) &&
  90                    (data[beg_run * 4] == data[(beg_run + run_count) * 4]))
  91                 run_count++;
  92         }
  93
  94         if ((old_run_count > 1) && (old_run_count == beg_run - cur)) {
  95             buf[0] = 128 + old_run_count;
  96             buf[1] = data[cur * 4];
  97             bytestream_put_buffer(buffer, buf, sizeof(buf));
  98             cur = beg_run;
  99         }
 100
 101         while (cur < beg_run) {
 102             int nonrun_count = FFMIN(128, beg_run - cur);
 103             buf[0] = nonrun_count;
 104             bytestream_put_byte(buffer, buf[0]);
 105             for (int n = 0; n < nonrun_count; n++)
 106                 bytestream_put_byte(buffer, data[(cur + n) * 4]);
 107             cur += nonrun_count;
 108         }
 109
 110         if (run_count >= MIN_RLE) {
 111             buf[0] = 128 + run_count;
 112             buf[1] = data[beg_run * 4];
 113             bytestream_put_buffer(buffer, buf, sizeof(buf));
 114             cur += run_count;
 115         }
 116     }
 117 }
 118
 119 static int hdr_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
 120                             const AVFrame *frame, int *got_packet)
 121 {
 122     HDREncContext *s = avctx->priv_data;
 123     int64_t packet_size;
 124     uint8_t *buf;
 125     int ret;
 126
 127     packet_size = avctx->height * 4LL + avctx->width * avctx->height * 8LL + 1024LL;
 128     if ((ret = ff_get_encode_buffer(avctx, pkt, packet_size, 0)) < 0)
 129         return ret;
 130
 131     buf = pkt->data;
 132     bytestream_put_str(&buf, "#?RADIANCE\n");
 133     bytestream_put_str(&buf, "SOFTWARE=lavc\n");
 134     ret = snprintf(buf, 32, "PIXASPECT=%f\n", av_q2d(av_inv_q(avctx->sample_aspect_ratio)));
 135     if (ret > 0)
 136         buf += ret;
 137     bytestream_put_str(&buf, "FORMAT=32-bit_rle_rgbe\n\n");
 138     ret = snprintf(buf, 32, "-Y %d +X %d\n", avctx->height, avctx->width);
 139     if (ret > 0)
 140         buf += ret;
 141
 142     for (int y = 0; y < avctx->height; y++) {
 143         const float *red   = (const float *)(frame->data[2] + y * frame->linesize[2]);
 144         const float *green = (const float *)(frame->data[0] + y * frame->linesize[0]);
 145         const float *blue  = (const float *)(frame->data[1] + y * frame->linesize[1]);
 146
 147         if (avctx->width < 8 || avctx->width > 0x7fff) {
 148             for (int x = 0; x < avctx->width; x++) {
 149                 float2rgbe(buf, red[x], green[x], blue[x]);
 150                 buf += 4;
 151             }
 152         } else {
 153             bytestream_put_byte(&buf, 2);
 154             bytestream_put_byte(&buf, 2);
 155             bytestream_put_byte(&buf, avctx->width >> 8);
 156             bytestream_put_byte(&buf, avctx->width & 0xFF);
 157
 158             for (int x = 0; x < avctx->width; x++)
 159                 float2rgbe(s->scanline + 4 * x, red[x], green[x], blue[x]);
 160             for (int p = 0; p < 4; p++)
 161                 rle(&buf, s->scanline + p, avctx->width);
 162         }
 163     }
 164
 165     pkt->flags |= AV_PKT_FLAG_KEY;
 166
 167     av_shrink_packet(pkt, buf - pkt->data);
 168
 169     *got_packet = 1;
 170
 171     return 0;
 172 }
 173
 174 const FFCodec ff_hdr_encoder = {
 175     .p.name         = "hdr",
 176     CODEC_LONG_NAME("HDR (Radiance RGBE format) image"),
 177     .priv_data_size = sizeof(HDREncContext),
 178     .p.type         = AVMEDIA_TYPE_VIDEO,
 179     .p.id           = AV_CODEC_ID_RADIANCE_HDR,
 180     .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS |
 181                       AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,
 182     .init           = hdr_encode_init,
 183     FF_CODEC_ENCODE_CB(hdr_encode_frame),
 184     .close          = hdr_encode_close,
 185     .p.pix_fmts     = (const enum AVPixelFormat[]){
 186         AV_PIX_FMT_GBRPF32,
 187         AV_PIX_FMT_NONE
 188     },
 189     .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,
 190 };