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FFmpeg/libavcodec/hdrenc.c

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/*
* Radiance HDR image format
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/mem.h"
#include "avcodec.h"
#include "bytestream.h"
#include "codec_internal.h"
#include "encode.h"
typedef struct HDREncContext {
uint8_t *scanline;
} HDREncContext;
static av_cold int hdr_encode_init(AVCodecContext *avctx)
{
HDREncContext *s = avctx->priv_data;
s->scanline = av_calloc(avctx->width * 4, sizeof(*s->scanline));
if (!s->scanline)
return AVERROR(ENOMEM);
return 0;
}
static av_cold int hdr_encode_close(AVCodecContext *avctx)
{
HDREncContext *s = avctx->priv_data;
av_freep(&s->scanline);
return 0;
}
static void bytestream_put_str(uint8_t **buf, const char *const line)
{
bytestream_put_buffer(buf, line, strlen(line));
}
static void float2rgbe(uint8_t *rgbe, float red, float green, float blue)
{
float v;
int e;
v = FFMAX3(red, green, blue);
if (v < 1e-32f) {
rgbe[0] = rgbe[1] = rgbe[2] = rgbe[3] = 0;
} else {
v = frexpf(v, &e) * 256.f / v;
rgbe[0] = av_clip_uint8(red * v);
rgbe[1] = av_clip_uint8(green * v);
rgbe[2] = av_clip_uint8(blue * v);
rgbe[3] = av_clip_uint8(e + 128);
}
}
static void rle(uint8_t **buffer, const uint8_t *data, int width)
{
#define MIN_RLE 4
int cur = 0;
while (cur < width) {
int run_count = 0, old_run_count = 0;
int beg_run = cur;
uint8_t buf[2];
while (run_count < MIN_RLE && beg_run < width) {
beg_run += run_count;
old_run_count = run_count;
run_count = 1;
while ((beg_run + run_count < width) && (run_count < 127) &&
(data[beg_run * 4] == data[(beg_run + run_count) * 4]))
run_count++;
}
if ((old_run_count > 1) && (old_run_count == beg_run - cur)) {
buf[0] = 128 + old_run_count;
buf[1] = data[cur * 4];
bytestream_put_buffer(buffer, buf, sizeof(buf));
cur = beg_run;
}
while (cur < beg_run) {
int nonrun_count = FFMIN(128, beg_run - cur);
buf[0] = nonrun_count;
bytestream_put_byte(buffer, buf[0]);
for (int n = 0; n < nonrun_count; n++)
bytestream_put_byte(buffer, data[(cur + n) * 4]);
cur += nonrun_count;
}
if (run_count >= MIN_RLE) {
buf[0] = 128 + run_count;
buf[1] = data[beg_run * 4];
bytestream_put_buffer(buffer, buf, sizeof(buf));
cur += run_count;
}
}
}
static int hdr_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
const AVFrame *frame, int *got_packet)
{
HDREncContext *s = avctx->priv_data;
int64_t packet_size;
uint8_t *buf;
int ret;
packet_size = avctx->height * 4LL + avctx->width * avctx->height * 8LL + 1024LL;
if ((ret = ff_get_encode_buffer(avctx, pkt, packet_size, 0)) < 0)
return ret;
buf = pkt->data;
bytestream_put_str(&buf, "#?RADIANCE\n");
bytestream_put_str(&buf, "SOFTWARE=lavc\n");
ret = snprintf(buf, 32, "PIXASPECT=%f\n", av_q2d(av_inv_q(avctx->sample_aspect_ratio)));
if (ret > 0)
buf += ret;
bytestream_put_str(&buf, "FORMAT=32-bit_rle_rgbe\n\n");
ret = snprintf(buf, 32, "-Y %d +X %d\n", avctx->height, avctx->width);
if (ret > 0)
buf += ret;
for (int y = 0; y < avctx->height; y++) {
const float *red = (const float *)(frame->data[2] + y * frame->linesize[2]);
const float *green = (const float *)(frame->data[0] + y * frame->linesize[0]);
const float *blue = (const float *)(frame->data[1] + y * frame->linesize[1]);
if (avctx->width < 8 || avctx->width > 0x7fff) {
for (int x = 0; x < avctx->width; x++) {
float2rgbe(buf, red[x], green[x], blue[x]);
buf += 4;
}
} else {
bytestream_put_byte(&buf, 2);
bytestream_put_byte(&buf, 2);
bytestream_put_byte(&buf, avctx->width >> 8);
bytestream_put_byte(&buf, avctx->width & 0xFF);
for (int x = 0; x < avctx->width; x++)
float2rgbe(s->scanline + 4 * x, red[x], green[x], blue[x]);
for (int p = 0; p < 4; p++)
rle(&buf, s->scanline + p, avctx->width);
}
}
pkt->flags |= AV_PKT_FLAG_KEY;
av_shrink_packet(pkt, buf - pkt->data);
*got_packet = 1;
return 0;
}
const FFCodec ff_hdr_encoder = {
.p.name = "hdr",
CODEC_LONG_NAME("HDR (Radiance RGBE format) image"),
.priv_data_size = sizeof(HDREncContext),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_RADIANCE_HDR,
.p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS |
AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,
.init = hdr_encode_init,
FF_CODEC_ENCODE_CB(hdr_encode_frame),
.close = hdr_encode_close,
.p.pix_fmts = (const enum AVPixelFormat[]){
AV_PIX_FMT_GBRPF32,
AV_PIX_FMT_NONE
},
.caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
};