Alias PIX image encoder and decoder

1 files changed, 128 insertions, 0 deletions

diff --git a/libavcodec/aliaspixdec.c b/libavcodec/aliaspixdec.c
new file mode 100644
index 0000000000..8969e1765e
--- /dev/null
+++ b/libavcodec/aliaspixdec.c
@@ -0,0 +1,128 @@
+/*
+ * Alias PIX image decoder
+ * 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 int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
+                        AVPacket *avpkt)
+{
+    AVFrame *f = data;
+    GetByteContext gb;
+    int width, height, ret, bits_pixel, pixel;
+    uint8_t *out_buf;
+    uint8_t count;
+    int x, y;
+
+    bytestream2_init(&gb, avpkt->data, avpkt->size);
+
+    if (bytestream2_get_bytes_left(&gb) < ALIAS_HEADER_SIZE) {
+        av_log(avctx, AV_LOG_ERROR, "Header too small %d.\n", avpkt->size);
+        return AVERROR_INVALIDDATA;
+    }
+
+    width  = bytestream2_get_be16u(&gb);
+    height = bytestream2_get_be16u(&gb);
+    bytestream2_skipu(&gb, 4); // obsolete X, Y offset
+    bits_pixel = bytestream2_get_be16u(&gb);
+
+    if (bits_pixel == 24)
+        avctx->pix_fmt = AV_PIX_FMT_BGR24;
+    else if (bits_pixel == 8)
+        avctx->pix_fmt = AV_PIX_FMT_GRAY8;
+    else {
+        av_log(avctx, AV_LOG_ERROR, "Invalid pixel format.\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    ret = ff_set_dimensions(avctx, width, height);
+    if (ret < 0)
+        return ret;
+
+    ret = ff_get_buffer(avctx, f, 0);
+    if (ret < 0)
+        return ret;
+
+    f->pict_type = AV_PICTURE_TYPE_I;
+    f->key_frame = 1;
+
+    x = 0;
+    y = 1;
+    out_buf = f->data[0];
+    while (bytestream2_get_bytes_left(&gb) > 0) {
+        int i;
+
+        /* set buffer at the right position at every new line */
+        if (x == avctx->width) {
+            x = 0;
+            out_buf = f->data[0] + f->linesize[0] * y++;
+            if (y > avctx->height) {
+                av_log(avctx, AV_LOG_ERROR,
+                       "Ended frame decoding with %d bytes left.\n",
+                       bytestream2_get_bytes_left(&gb));
+                return AVERROR_INVALIDDATA;
+            }
+        }
+
+        /* read packet and copy data */
+        count = bytestream2_get_byteu(&gb);
+        if (!count || x + count > avctx->width) {
+            av_log(avctx, AV_LOG_ERROR, "Invalid run length %d.\n", count);
+            return AVERROR_INVALIDDATA;
+        }
+
+        if (avctx->pix_fmt == AV_PIX_FMT_BGR24) {
+            pixel = bytestream2_get_be24(&gb);
+            for (i = 0; i < count; i++) {
+                AV_WB24(out_buf, pixel);
+                out_buf += 3;
+            }
+        } else { // AV_PIX_FMT_GRAY8
+            pixel = bytestream2_get_byte(&gb);
+            for (i = 0; i < count; i++)
+                *out_buf++ = pixel;
+        }
+
+        x += i;
+    }
+
+    if (x != width || y != height) {
+        av_log(avctx, AV_LOG_ERROR, "Picture stopped at %d,%d.\n", x, y);
+        return AVERROR_INVALIDDATA;
+    }
+
+    *got_frame = 1;
+    return avpkt->size;
+}
+
+AVCodec ff_alias_pix_decoder = {
+    .name         = "alias_pix",
+    .long_name    = NULL_IF_CONFIG_SMALL("Alias/Wavefront PIX image"),
+    .type         = AVMEDIA_TYPE_VIDEO,
+    .id           = AV_CODEC_ID_ALIAS_PIX,
+    .decode       = decode_frame,
+    .capabilities = CODEC_CAP_DR1,
+};