Alias PIX image encoder and decoder

1 files changed, 134 insertions, 0 deletions

diff --git a/libavcodec/aliaspixenc.c b/libavcodec/aliaspixenc.c
new file mode 100644
index 0000000000..47e06129d5
--- /dev/null
+++ b/libavcodec/aliaspixenc.c
@@ -0,0 +1,134 @@
+/*
+ * Alias PIX image encoder
+ * Copyright (C) 2014 Vittorio Giovara <vittorio.giovara@gmail.com>
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/intreadwrite.h"
+
+#include "avcodec.h"
+#include "bytestream.h"
+#include "internal.h"
+
+#define ALIAS_HEADER_SIZE 10
+
+static av_cold int encode_init(AVCodecContext *avctx)
+{
+    avctx->coded_frame = av_frame_alloc();
+    if (!avctx->coded_frame)
+        return AVERROR(ENOMEM);
+    return 0;
+}
+
+static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
+                        const AVFrame *frame, int *got_packet)
+{
+    int width, height, bits_pixel, i, j, length, ret;
+    uint8_t *in_buf, *buf;
+
+    avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;
+    avctx->coded_frame->key_frame = 1;
+
+    width  = avctx->width;
+    height = avctx->height;
+
+    if (width > 65535 || height > 65535 ||
+        width * height >= INT_MAX / 4 - ALIAS_HEADER_SIZE) {
+        av_log(avctx, AV_LOG_ERROR, "Invalid image size %dx%d.\n", width, height);
+        return AVERROR_INVALIDDATA;
+    }
+
+    switch (avctx->pix_fmt) {
+    case AV_PIX_FMT_GRAY8:
+        bits_pixel = 8;
+        break;
+    case AV_PIX_FMT_BGR24:
+        bits_pixel = 24;
+        break;
+    default:
+        return AVERROR(EINVAL);
+    }
+
+    length = ALIAS_HEADER_SIZE + 4 * width * height; // max possible
+    if ((ret = ff_alloc_packet(pkt, length)) < 0) {
+        av_log(avctx, AV_LOG_ERROR, "Error getting output packet of size %d.\n", length);
+        return ret;
+    }
+
+    buf = pkt->data;
+
+    /* Encode header. */
+    bytestream_put_be16(&buf, width);
+    bytestream_put_be16(&buf, height);
+    bytestream_put_be32(&buf, 0); /* X, Y offset */
+    bytestream_put_be16(&buf, bits_pixel);
+
+    for (j = 0; j < height; j++) {
+        in_buf = frame->data[0] + frame->linesize[0] * j;
+        for (i = 0; i < width; ) {
+            int count = 0;
+            int pixel;
+
+            if (avctx->pix_fmt == AV_PIX_FMT_GRAY8) {
+                pixel = *in_buf;
+                while (count < 255 && count + i < width && pixel == *in_buf) {
+                    count++;
+                    in_buf++;
+                }
+                bytestream_put_byte(&buf, count);
+                bytestream_put_byte(&buf, pixel);
+            } else { /* AV_PIX_FMT_BGR24 */
+                pixel = AV_RB24(in_buf);
+                while (count < 255 && count + i < width &&
+                       pixel == AV_RB24(in_buf)) {
+                    count++;
+                    in_buf += 3;
+                }
+                bytestream_put_byte(&buf, count);
+                bytestream_put_be24(&buf, pixel);
+            }
+            i += count;
+        }
+    }
+
+    /* Total length */
+    av_shrink_packet(pkt, buf - pkt->data);
+    pkt->flags |= AV_PKT_FLAG_KEY;
+    *got_packet = 1;
+
+    return 0;
+}
+
+static av_cold int encode_close(AVCodecContext *avctx)
+{
+    av_frame_free(&avctx->coded_frame);
+    return 0;
+}
+
+AVCodec ff_alias_pix_encoder = {
+    .name      = "alias_pix",
+    .long_name = NULL_IF_CONFIG_SMALL("Alias/Wavefront PIX image"),
+    .type      = AVMEDIA_TYPE_VIDEO,
+    .id        = AV_CODEC_ID_ALIAS_PIX,
+    .init      = encode_init,
+    .encode2   = encode_frame,
+    .close     = encode_close,
+    .pix_fmts  = (const enum AVPixelFormat[]) {
+        AV_PIX_FMT_BGR24, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE
+    },
+};