avcodec: add Mandsoft Screen Capture Codec decoder

Signed-off-by: Paul B Mahol <onemda@gmail.com>

1 files changed, 231 insertions, 0 deletions

diff --git a/libavcodec/mscc.c b/libavcodec/mscc.c
new file mode 100644
index 0000000000..c42889ae73
--- /dev/null
+++ b/libavcodec/mscc.c
@@ -0,0 +1,231 @@
+/*
+ * Mandsoft Screen Capture Codec decoder
+ *
+ * Copyright (c) 2017 Paul B Mahol
+ *
+ * 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 <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "avcodec.h"
+#include "bytestream.h"
+#include "internal.h"
+
+#include <zlib.h>
+
+typedef struct MSCCContext {
+    unsigned          bpp;
+    unsigned int      decomp_size;
+    uint8_t          *decomp_buf;
+    unsigned int      uncomp_size;
+    uint8_t          *uncomp_buf;
+    z_stream          zstream;
+} MSCCContext;
+
+static int rle_uncompress(AVCodecContext *avctx, GetByteContext *gb, PutByteContext *pb, int bpp)
+{
+    while (bytestream2_get_bytes_left(gb) > 0) {
+        uint32_t fill;
+        int j;
+        unsigned run = bytestream2_get_byte(gb);
+
+        if (run) {
+            switch (avctx->bits_per_coded_sample) {
+            case 8:
+                fill = bytestream2_get_byte(gb);
+                break;
+            case 16:
+                fill = bytestream2_get_le16(gb);
+                break;
+            case 24:
+                fill = bytestream2_get_le24(gb);
+                break;
+            case 32:
+                fill = bytestream2_get_le32(gb);
+                break;
+            }
+
+            for (j = 0; j < run; j++) {
+                switch (avctx->bits_per_coded_sample) {
+                case 8:
+                    bytestream2_put_byte(pb, fill);
+                    break;
+                case 16:
+                    bytestream2_put_le16(pb, fill);
+                    break;
+                case 24:
+                    bytestream2_put_le24(pb, fill);
+                    break;
+                case 32:
+                    bytestream2_put_le32(pb, fill);
+                    break;
+                }
+            }
+        } else {
+            unsigned copy = bytestream2_get_byte(gb);
+
+            if (copy == 1) {
+                return 0;
+            } else if (copy == 2) {
+                unsigned x, y;
+
+                x = bytestream2_get_byte(gb);
+                y = bytestream2_get_byte(gb);
+
+                bytestream2_skip_p(pb, x * bpp);
+                bytestream2_skip_p(pb, y * bpp * avctx->width);
+            } else {
+                for (j = 0; j < copy; j++) {
+                    switch (avctx->bits_per_coded_sample) {
+                    case 8:
+                        bytestream2_put_byte(pb, bytestream2_get_byte(gb));
+                        break;
+                    case 16:
+                        bytestream2_put_le16(pb, bytestream2_get_le16(gb));
+                        break;
+                    case 24:
+                        bytestream2_put_le24(pb, bytestream2_get_le24(gb));
+                        break;
+                    case 32:
+                        bytestream2_put_le32(pb, bytestream2_get_le32(gb));
+                        break;
+                    }
+                }
+            }
+        }
+    }
+
+    return AVERROR_INVALIDDATA;
+}
+
+static int decode_frame(AVCodecContext *avctx,
+                        void *data, int *got_frame,
+                        AVPacket *avpkt)
+{
+    MSCCContext *s = avctx->priv_data;
+    AVFrame *frame = data;
+    GetByteContext gb;
+    PutByteContext pb;
+    int ret, j;
+
+    if (avpkt->size < 3)
+        return AVERROR_INVALIDDATA;
+    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
+        return ret;
+
+    avpkt->data[2] ^= avpkt->data[0];
+
+    ret = inflateReset(&s->zstream);
+    if (ret != Z_OK) {
+        av_log(avctx, AV_LOG_ERROR, "Inflate reset error: %d\n", ret);
+        return AVERROR_UNKNOWN;
+    }
+    s->zstream.next_in   = avpkt->data + 2;
+    s->zstream.avail_in  = avpkt->size - 2;
+    s->zstream.next_out  = s->decomp_buf;
+    s->zstream.avail_out = s->decomp_size;
+    ret = inflate(&s->zstream, Z_FINISH);
+    if (ret != Z_STREAM_END) {
+        av_log(avctx, AV_LOG_ERROR, "Inflate error: %d\n", ret);
+        return AVERROR_UNKNOWN;
+    }
+
+    bytestream2_init(&gb, s->decomp_buf, s->zstream.total_out);
+    bytestream2_init_writer(&pb, s->uncomp_buf, s->uncomp_size);
+
+    ret = rle_uncompress(avctx, &gb, &pb, s->bpp);
+    if (ret)
+        return ret;
+
+    for (j = 0; j < avctx->height; j++) {
+        memcpy(frame->data[0] + (avctx->height - j - 1) * frame->linesize[0],
+               s->uncomp_buf + s->bpp * j * avctx->width, s->bpp * avctx->width);
+    }
+
+    frame->key_frame = 1;
+    frame->pict_type = AV_PICTURE_TYPE_I;
+
+    *got_frame = 1;
+
+    return avpkt->size;
+}
+
+static av_cold int decode_init(AVCodecContext *avctx)
+{
+    MSCCContext *s = avctx->priv_data;
+    int zret;
+
+    switch (avctx->bits_per_coded_sample) {
+    case  8: avctx->pix_fmt = AV_PIX_FMT_GRAY8;  break;
+    case 16: avctx->pix_fmt = AV_PIX_FMT_RGB555; break;
+    case 24: avctx->pix_fmt = AV_PIX_FMT_BGR24;  break;
+    case 32: avctx->pix_fmt = AV_PIX_FMT_BGRA;   break;
+    default:
+        av_log(avctx, AV_LOG_ERROR, "Unsupported bitdepth %i\n", avctx->bits_per_coded_sample);
+        return AVERROR_INVALIDDATA;
+    }
+
+    s->bpp = avctx->bits_per_coded_sample >> 3;
+    memset(&s->zstream, 0, sizeof(z_stream));
+
+    s->decomp_size = 4 * avctx->height * ((avctx->width * avctx->bits_per_coded_sample + 31) / 32);
+    if (!(s->decomp_buf = av_malloc(s->decomp_size)))
+        return AVERROR(ENOMEM);
+
+    s->uncomp_size = 4 * avctx->height * ((avctx->width * avctx->bits_per_coded_sample + 31) / 32);
+    if (!(s->uncomp_buf = av_malloc(s->uncomp_size)))
+        return AVERROR(ENOMEM);
+
+    s->zstream.zalloc = Z_NULL;
+    s->zstream.zfree = Z_NULL;
+    s->zstream.opaque = Z_NULL;
+    zret = inflateInit(&s->zstream);
+    if (zret != Z_OK) {
+        av_log(avctx, AV_LOG_ERROR, "Inflate init error: %d\n", zret);
+        return AVERROR_UNKNOWN;
+    }
+
+    return 0;
+}
+
+static av_cold int decode_close(AVCodecContext *avctx)
+{
+    MSCCContext *s = avctx->priv_data;
+
+    av_freep(&s->decomp_buf);
+    s->decomp_size = 0;
+    av_freep(&s->uncomp_buf);
+    s->uncomp_size = 0;
+    inflateEnd(&s->zstream);
+
+    return 0;
+}
+
+AVCodec ff_mscc_decoder = {
+    .name             = "mscc",
+    .long_name        = NULL_IF_CONFIG_SMALL("Mandsoft Screen Capture Codec"),
+    .type             = AVMEDIA_TYPE_VIDEO,
+    .id               = AV_CODEC_ID_MSCC,
+    .priv_data_size   = sizeof(MSCCContext),
+    .init             = decode_init,
+    .close            = decode_close,
+    .decode           = decode_frame,
+    .capabilities     = AV_CODEC_CAP_DR1,
+};