avcodec: add Radiance HDR image format support

1 files changed, 189 insertions, 0 deletions

diff --git a/libavcodec/hdrenc.c b/libavcodec/hdrenc.c
new file mode 100644
index 0000000000..5860030e0d
--- /dev/null
+++ b/libavcodec/hdrenc.c
@@ -0,0 +1,189 @@
+/*
+ * 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/imgutils.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->width * avctx->height * 4LL + 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",
+    .p.long_name    = NULL_IF_CONFIG_SMALL("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,
+    .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_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
+};