[FFmpeg-devel] avcodec: add RemotelyAnywhere Screen Capture decoder

Submitted by Paul B Mahol on Sept. 5, 2018, 7:22 p.m.

Details

Message ID 20180905192212.25472-1-onemda@gmail.com
State New
Headers show

Commit Message

Paul B Mahol Sept. 5, 2018, 7:22 p.m.
Signed-off-by: Paul B Mahol <onemda@gmail.com>
---
 configure               |   1 +
 libavcodec/Makefile     |   1 +
 libavcodec/allcodecs.c  |   1 +
 libavcodec/avcodec.h    |   1 +
 libavcodec/codec_desc.c |   7 +
 libavcodec/rasc.c       | 795 ++++++++++++++++++++++++++++++++++++++++
 libavformat/riff.c      |   1 +
 7 files changed, 807 insertions(+)
 create mode 100644 libavcodec/rasc.c

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diff --git a/configure b/configure
index 0d6ee0abfc..595be65f2c 100755
--- a/configure
+++ b/configure
@@ -2719,6 +2719,7 @@  qdm2_decoder_select="mdct rdft mpegaudiodsp"
 ra_144_decoder_select="audiodsp"
 ra_144_encoder_select="audio_frame_queue lpc audiodsp"
 ralf_decoder_select="golomb"
+rasc_decoder_deps="zlib"
 rawvideo_decoder_select="bswapdsp"
 rscc_decoder_deps="zlib"
 rtjpeg_decoder_select="me_cmp"
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index f8673f0121..ceec1df972 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -536,6 +536,7 @@  OBJS-$(CONFIG_RA_144_DECODER)          += ra144dec.o ra144.o celp_filters.o
 OBJS-$(CONFIG_RA_144_ENCODER)          += ra144enc.o ra144.o celp_filters.o
 OBJS-$(CONFIG_RA_288_DECODER)          += ra288.o celp_filters.o
 OBJS-$(CONFIG_RALF_DECODER)            += ralf.o
+OBJS-$(CONFIG_RASC_DECODER)            += rasc.o
 OBJS-$(CONFIG_RAWVIDEO_DECODER)        += rawdec.o
 OBJS-$(CONFIG_RAWVIDEO_ENCODER)        += rawenc.o
 OBJS-$(CONFIG_REALTEXT_DECODER)        += realtextdec.o ass.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index a461131c78..8fc1aeab79 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -248,6 +248,7 @@  extern AVCodec ff_r10k_encoder;
 extern AVCodec ff_r10k_decoder;
 extern AVCodec ff_r210_encoder;
 extern AVCodec ff_r210_decoder;
+extern AVCodec ff_rasc_decoder;
 extern AVCodec ff_rawvideo_encoder;
 extern AVCodec ff_rawvideo_decoder;
 extern AVCodec ff_rl2_decoder;
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index b6688b7af3..719c181a08 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -451,6 +451,7 @@  enum AVCodecID {
     AV_CODEC_ID_PROSUMER,
     AV_CODEC_ID_MWSC,
     AV_CODEC_ID_WCMV,
+    AV_CODEC_ID_RASC,
 
     /* various PCM "codecs" */
     AV_CODEC_ID_FIRST_AUDIO = 0x10000,     ///< A dummy id pointing at the start of audio codecs
diff --git a/libavcodec/codec_desc.c b/libavcodec/codec_desc.c
index 46dfe3f5e5..67a30542d1 100644
--- a/libavcodec/codec_desc.c
+++ b/libavcodec/codec_desc.c
@@ -1682,6 +1682,13 @@  static const AVCodecDescriptor codec_descriptors[] = {
         .long_name = NULL_IF_CONFIG_SMALL("WinCAM Motion Video"),
         .props     = AV_CODEC_PROP_LOSSLESS,
     },
+    {
+        .id        = AV_CODEC_ID_RASC,
+        .type      = AVMEDIA_TYPE_VIDEO,
+        .name      = "rasc",
+        .long_name = NULL_IF_CONFIG_SMALL("RemotelyAnywhere Screen Capture"),
+        .props     = AV_CODEC_PROP_LOSSY,
+    },
 
     /* various PCM "codecs" */
     {
diff --git a/libavcodec/rasc.c b/libavcodec/rasc.c
new file mode 100644
index 0000000000..a50075388a
--- /dev/null
+++ b/libavcodec/rasc.c
@@ -0,0 +1,795 @@ 
+/*
+ * RemotelyAnywhere Screen Capture decoder
+ *
+ * Copyright (c) 2018 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 "libavutil/avassert.h"
+#include "libavutil/imgutils.h"
+#include "libavutil/opt.h"
+
+#include "avcodec.h"
+#include "bytestream.h"
+#include "internal.h"
+
+#include <zlib.h>
+
+#define KBND MKTAG('K', 'B', 'N', 'D')
+#define FINT MKTAG('F', 'I', 'N', 'T')
+#define INIT MKTAG('I', 'N', 'I', 'T')
+#define BNDL MKTAG('B', 'N', 'D', 'L')
+#define KFRM MKTAG('K', 'F', 'R', 'M')
+#define DLTA MKTAG('D', 'L', 'T', 'A')
+#define MOUS MKTAG('M', 'O', 'U', 'S')
+#define MPOS MKTAG('M', 'P', 'O', 'S')
+#define MOVE MKTAG('M', 'O', 'V', 'E')
+#define EMPT MKTAG('E', 'M', 'P', 'T')
+
+typedef struct RASCContext {
+    AVClass        *class;
+    int             skip_cursor;
+    GetByteContext  gb;
+    uint8_t        *delta;
+    int             delta_size;
+    uint8_t        *cursor;
+    int             cursor_size;
+    unsigned        cursor_w;
+    unsigned        cursor_h;
+    unsigned        cursor_x;
+    unsigned        cursor_y;
+    z_stream        zstream;
+    AVFrame        *frame;
+    AVFrame        *frame1;
+    AVFrame        *frame2;
+} RASCContext;
+
+static void clear_plane(AVCodecContext *avctx, AVFrame *frame)
+{
+    uint8_t *dst = frame->data[0];
+
+    for (int y = 0; y < avctx->height; y++) {
+        memset(dst, 0, avctx->width);
+        dst += frame->linesize[0];
+    }
+}
+
+static void copy_plane(AVCodecContext *avctx, AVFrame *src, AVFrame *dst)
+{
+    uint8_t *srcp = src->data[0];
+    uint8_t *dstp = dst->data[0];
+
+    for (int y = 0; y < avctx->height; y++) {
+        memcpy(dstp, srcp, avctx->width);
+        srcp += src->linesize[0];
+        dstp += dst->linesize[0];
+    }
+}
+
+static int init_frames(AVCodecContext *avctx)
+{
+    RASCContext *s = avctx->priv_data;
+    int ret;
+
+    av_frame_unref(s->frame1);
+    if ((ret = ff_get_buffer(avctx, s->frame1, 0)) < 0)
+        return ret;
+
+    av_frame_unref(s->frame2);
+    if ((ret = ff_get_buffer(avctx, s->frame2, 0)) < 0)
+        return ret;
+
+    clear_plane(avctx, s->frame2);
+    clear_plane(avctx, s->frame1);
+
+    av_frame_unref(s->frame);
+    if ((ret = ff_get_buffer(avctx, s->frame, 0)) < 0)
+        return ret;
+
+    return 0;
+}
+
+static int decode_fint(AVCodecContext *avctx,
+                       AVPacket *avpkt, unsigned size)
+{
+    RASCContext *s = avctx->priv_data;
+    GetByteContext *gb = &s->gb;
+    unsigned w, h;
+    uint32_t *pal;
+    int ret;
+
+    if (bytestream2_peek_le32(gb) != 0x65) {
+        clear_plane(avctx, s->frame2);
+        clear_plane(avctx, s->frame1);
+        return 0;
+    }
+
+    bytestream2_skip(gb, 8);
+    w = bytestream2_get_le32(gb);
+    h = bytestream2_get_le32(gb);
+    bytestream2_skip(gb, 56);
+
+    if (w != avctx->width || h != avctx->height) {
+        ret = ff_set_dimensions(avctx, w, h);
+        if (ret < 0)
+            return ret;
+        avctx->width  = w;
+        avctx->height = h;
+
+        ret = init_frames(avctx);
+        if (ret < 0)
+            return ret;
+    }
+
+    pal = (uint32_t *)s->frame->data[1];
+    for (int i = 0; i < 256; i++) {
+        pal[i] = bytestream2_get_le32(gb) | 0xFF000000u;
+    }
+
+    return 0;
+}
+
+static int decode_zlib(AVCodecContext *avctx, AVPacket *avpkt,
+                       unsigned size, unsigned uncompressed_size)
+{
+    RASCContext *s = avctx->priv_data;
+    GetByteContext *gb = &s->gb;
+    int zret;
+
+    zret = inflateReset(&s->zstream);
+    if (zret != Z_OK) {
+        av_log(avctx, AV_LOG_ERROR, "Inflate reset error: %d\n", zret);
+        return AVERROR_EXTERNAL;
+    }
+
+    av_fast_padded_malloc(&s->delta, &s->delta_size, uncompressed_size);
+    if (!s->delta)
+        return AVERROR(ENOMEM);
+
+    s->zstream.next_in  = avpkt->data + bytestream2_tell(gb);
+    s->zstream.avail_in = FFMIN(size, bytestream2_get_bytes_left(gb));
+
+    s->zstream.next_out  = s->delta;
+    s->zstream.avail_out = s->delta_size;
+
+    zret = inflate(&s->zstream, Z_FINISH);
+    if (zret != Z_STREAM_END) {
+        av_log(avctx, AV_LOG_ERROR,
+               "Inflate failed with return code: %d.\n", zret);
+        return AVERROR_INVALIDDATA;
+    }
+
+    return 0;
+}
+
+static int decode_move(AVCodecContext *avctx,
+                       AVPacket *avpkt, unsigned size)
+{
+    RASCContext *s = avctx->priv_data;
+    GetByteContext *gb = &s->gb;
+    GetByteContext mc;
+    unsigned pos, compression, nb_moves;
+    unsigned uncompressed_size;
+    int ret;
+
+    pos = bytestream2_tell(gb);
+    bytestream2_skip(gb, 8);
+    nb_moves = bytestream2_get_le32(gb);
+    bytestream2_skip(gb, 8);
+    compression = bytestream2_get_le32(gb);
+
+    if (nb_moves > INT32_MAX / 16)
+        return AVERROR_INVALIDDATA;
+
+    uncompressed_size = 16 * nb_moves;
+
+    if (compression == 1) {
+        ret = decode_zlib(avctx, avpkt,
+                          size - (bytestream2_tell(gb) - pos),
+                          uncompressed_size);
+        if (ret < 0)
+            return ret;
+        bytestream2_init(&mc, s->delta, uncompressed_size);
+    } else if (compression == 0) {
+        bytestream2_init(&mc, avpkt->data + bytestream2_tell(gb),
+                         bytestream2_get_bytes_left(gb));
+    } else if (compression == 2) {
+        avpriv_request_sample(avctx, "compression %d", compression);
+        return AVERROR_PATCHWELCOME;
+    } else {
+        return AVERROR_INVALIDDATA;
+    }
+
+    if (bytestream2_get_bytes_left(&mc) < uncompressed_size)
+        return AVERROR_INVALIDDATA;
+
+    for (int i = 0; i < nb_moves; i++) {
+        int type, start_x, start_y, end_x, end_y, mov_x, mov_y;
+        uint8_t *e2, *b0, *b1, *b2;
+        int w, h;
+
+        type = bytestream2_get_le16(&mc);
+        start_x = bytestream2_get_le16(&mc);
+        start_y = bytestream2_get_le16(&mc);
+        end_x = bytestream2_get_le16(&mc);
+        end_y = bytestream2_get_le16(&mc);
+        mov_x = bytestream2_get_le16(&mc);
+        mov_y = bytestream2_get_le16(&mc);
+        bytestream2_skip(&mc, 2);
+
+        if (start_x >= avctx->width || start_y >= avctx->height ||
+            end_x >= avctx->width || end_y >= avctx->height ||
+            mov_x >= avctx->width || mov_y >= avctx->height) {
+            continue;
+        }
+
+        if (start_x >= end_x || start_y >= end_y)
+            continue;
+
+        w = end_x - start_x;
+        h = end_y - start_y;
+
+        if (mov_x + w > avctx->width || mov_y + h > avctx->height)
+            continue;
+
+        b0 = s->frame->data[0] + s->frame->linesize[0] * (start_y + h) + start_x;
+        b1 = s->frame1->data[0] + s->frame1->linesize[0] * (start_y + h) + start_x;
+        b2 = s->frame2->data[0] + s->frame2->linesize[0] * (start_y + h) + start_x;
+        e2 = s->frame2->data[0] + s->frame2->linesize[0] * (mov_y + h) + mov_x;
+
+        if (type == 2) {
+            for (int j = 0; j < h; j++) {
+                memcpy(b1, b2, w);
+                b1 -= s->frame1->linesize[0];
+                b2 -= s->frame2->linesize[0];
+            }
+        } else if (type == 1) {
+            for (int j = 0; j < h; j++) {
+                memset(b0, 0, w);
+                memset(b2, 0, w);
+                b0 -= s->frame1->linesize[0];
+                b2 -= s->frame2->linesize[0];
+            }
+        } else if (type == 0) {
+            uint8_t *buffer;
+
+            av_fast_padded_malloc(&s->delta, &s->delta_size, w * h);
+            buffer = s->delta;
+            if (!buffer)
+                return AVERROR(ENOMEM);
+
+            for (int j = 0; j < h; j++) {
+                memcpy(buffer + j * w, e2, w);
+                e2 -= s->frame2->linesize[0];
+            }
+
+            for (int j = 0; j < h; j++) {
+                memcpy(b0, buffer + j * w, w);
+                memcpy(b2, buffer + j * w, w);
+                b0 -= s->frame->linesize[0];
+                b2 -= s->frame2->linesize[0];
+            }
+        } else {
+            return AVERROR_INVALIDDATA;
+        }
+    }
+
+    bytestream2_skip(gb, size - (bytestream2_tell(gb) - pos));
+
+    return 0;
+}
+
+#define NEXT_LINE                        \
+    if (cx >= w) {                       \
+        cx = 0;                          \
+        cy--;                            \
+        dst -= s->frame->linesize[0];    \
+        b1 -= s->frame1->linesize[0];    \
+        b2 -= s->frame2->linesize[0];    \
+    }                                    \
+    len--;
+
+static int decode_dlta(AVCodecContext *avctx,
+                       AVPacket *avpkt, unsigned size)
+{
+    RASCContext *s = avctx->priv_data;
+    GetByteContext *gb = &s->gb;
+    GetByteContext dc;
+    unsigned uncompressed_size, pos;
+    unsigned x, y, w, h;
+    int ret, cx, cy, compression;
+    uint8_t *dst, *b1, *b2;
+
+    if (!s->frame || !s->frame->data[0])
+        return AVERROR_INVALIDDATA;
+
+    pos = bytestream2_tell(gb);
+    bytestream2_skip(gb, 12);
+    uncompressed_size = bytestream2_get_le32(gb);
+    x = bytestream2_get_le32(gb);
+    y = bytestream2_get_le32(gb);
+    w = bytestream2_get_le32(gb);
+    h = bytestream2_get_le32(gb);
+
+    if (x >= avctx->width || y >= avctx->height ||
+        w > avctx->width || h > avctx->height)
+        return AVERROR_INVALIDDATA;
+
+    if (x + w > avctx->width || y + h > avctx->height)
+        return AVERROR_INVALIDDATA;
+
+    bytestream2_skip(gb, 4);
+    compression = bytestream2_get_le32(gb);
+
+    if (compression == 1) {
+        ret = decode_zlib(avctx, avpkt, size, uncompressed_size);
+        if (ret < 0)
+            return ret;
+        bytestream2_init(&dc, s->delta, uncompressed_size);
+    } else if (compression == 0) {
+        if (bytestream2_get_bytes_left(gb) < uncompressed_size)
+            return AVERROR_INVALIDDATA;
+        bytestream2_init(&dc, avpkt->data + bytestream2_tell(gb),
+                         uncompressed_size);
+    } else if (compression == 2) {
+        avpriv_request_sample(avctx, "compression %d", compression);
+        return AVERROR_PATCHWELCOME;
+    } else {
+        return AVERROR_INVALIDDATA;
+    }
+
+
+    dst = s->frame->data[0] + s->frame->linesize[0] * (y + h - 1) + x;
+    b1  = s->frame1->data[0] + s->frame1->linesize[0] * (y + h - 1) + x;
+    b2  = s->frame2->data[0] + s->frame2->linesize[0] * (y + h - 1) + x;
+    cx = 0, cy = h;
+    while (bytestream2_get_bytes_left(&dc) > 0) {
+        int type = bytestream2_get_byte(&dc);
+        int len = bytestream2_get_byte(&dc);
+        unsigned fill;
+
+        switch (type) {
+        case 1:
+            while (len > 0 && cy > 0) {
+                dst[cx] = b2[cx];
+                cx++;
+                NEXT_LINE
+            }
+            break;
+        case 2:
+            while (len > 0 && cy > 0) {
+                int v0 = b1[cx];
+                int v1 = b2[cx];
+
+                b2[cx] = v0;
+                dst[cx] = v0;
+                b1[cx] = v1;
+                cx++;
+                NEXT_LINE
+            }
+            break;
+        case 3:
+            while (len > 0 && cy > 0) {
+                fill = bytestream2_get_byte(&dc);
+                b1[cx] = b2[cx];
+                b2[cx] = fill;
+                dst[cx] = fill;
+                cx++;
+                NEXT_LINE
+            }
+            break;
+        case 4:
+            fill = bytestream2_get_byte(&dc);
+            while (len > 0 && cy > 0) {
+                AV_WL32(b1 + cx, AV_RL32(b2 + cx));
+                AV_WL32(dst + cx, fill);
+                AV_WL32(b2 + cx, fill);
+                cx++;
+                NEXT_LINE
+            }
+            break;
+        case 5:
+            fill = bytestream2_get_le16(&dc);
+            while (len > 0 && cy > 0) {
+                AV_WL16(dst + cx, fill);
+                cx += 2;
+                NEXT_LINE
+            }
+            break;
+        case 6:
+            fill = bytestream2_get_le24(&dc);
+            while (len > 0 && cy > 0) {
+                AV_WL24(dst + cx, fill);
+                cx += 3;
+                NEXT_LINE
+            }
+            break;
+        case 7:
+            fill = bytestream2_get_le32(&dc);
+            while (len > 0 && cy > 0) {
+                AV_WL32(dst + cx, fill);
+                AV_WL32(b1 + cx, AV_RL32(b2 + cx));
+                AV_WL32(b2 + cx, fill);
+                cx += 4;
+                NEXT_LINE
+            }
+            break;
+        case 10:
+            while (len > 0 && cy > 0) {
+                AV_WL32(dst + cx, AV_RL32(b2 + cx));
+                cx += 4;
+                NEXT_LINE
+            }
+            break;
+        case 12:
+            while (len > 0 && cy > 0) {
+                unsigned v0, v1;
+
+                v0 = AV_RL32(b2 + cx);
+                v1 = AV_RL32(b1 + cx);
+                AV_WL32(b2 + cx, v1);
+                AV_WL32(dst + cx, v1);
+                AV_WL32(b1 + cx, v0);
+                cx += 4;
+                NEXT_LINE
+            }
+            break;
+        case 13:
+            while (len > 0 && cy > 0) {
+                fill = bytestream2_get_le32(&dc);
+                AV_WL32(dst + cx, fill);
+                AV_WL32(b1 + cx, AV_RL32(b2 + cx));
+                AV_WL32(b2 + cx, fill);
+                cx += 4;
+                NEXT_LINE
+            }
+            break;
+        default:
+            printf("%d %d\n", type, bytestream2_tell(&dc));
+            bytestream2_seek(&dc, 0, SEEK_SET);
+            for (int i = 0; bytestream2_get_bytes_left(&dc) > 0; i++)
+                printf("%02X ", bytestream2_get_byte(&dc));
+            printf("\n");
+            return AVERROR_INVALIDDATA;
+        }
+    }
+
+    bytestream2_skip(gb, size - (bytestream2_tell(gb) - pos));
+
+    return 0;
+}
+
+static int decode_kfrm(AVCodecContext *avctx,
+                       AVPacket *avpkt, unsigned size)
+{
+    RASCContext *s = avctx->priv_data;
+    GetByteContext *gb = &s->gb;
+    uint8_t *dst, *cptr;
+    unsigned pos;
+    int zret, ret;
+
+    pos = bytestream2_tell(gb);
+    if (bytestream2_peek_le32(gb) == 0x65) {
+        ret = decode_fint(avctx, avpkt, size);
+        if (ret < 0)
+            return ret;
+    }
+
+    if (!s->frame || !s->frame->data[0])
+        return AVERROR_INVALIDDATA;
+
+    zret = inflateReset(&s->zstream);
+    if (zret != Z_OK) {
+        av_log(avctx, AV_LOG_ERROR, "Inflate reset error: %d\n", zret);
+        return AVERROR_EXTERNAL;
+    }
+
+    s->zstream.next_in  = avpkt->data + bytestream2_tell(gb);
+    s->zstream.avail_in = bytestream2_get_bytes_left(gb);
+
+    dst = s->frame->data[0] + (avctx->height - 1) * s->frame->linesize[0];
+    cptr = s->frame2->data[0] + (avctx->height - 1) * s->frame2->linesize[0];
+    for (int i = 0; i < avctx->height; i++) {
+        s->zstream.next_out  = dst;
+        s->zstream.avail_out = FFALIGN(avctx->width, 4);
+
+        zret = inflate(&s->zstream, Z_SYNC_FLUSH);
+        if (zret != Z_OK && zret != Z_STREAM_END) {
+            av_log(avctx, AV_LOG_ERROR,
+                   "Inflate failed with return code: %d.\n", zret);
+            return AVERROR_INVALIDDATA;
+        }
+
+        memcpy(cptr, dst, FFALIGN(avctx->width, 4));
+        dst -= s->frame->linesize[0];
+        cptr -= s->frame2->linesize[0];
+    }
+
+    dst = s->frame1->data[0] + (avctx->height - 1) * s->frame1->linesize[0];
+    for (int i = 0; i < avctx->height; i++) {
+        s->zstream.next_out  = dst;
+        s->zstream.avail_out = FFALIGN(avctx->width, 4);
+
+        zret = inflate(&s->zstream, Z_SYNC_FLUSH);
+        if (zret != Z_OK && zret != Z_STREAM_END) {
+            av_log(avctx, AV_LOG_ERROR,
+                   "Inflate failed with return code: %d.\n", zret);
+            return AVERROR_INVALIDDATA;
+        }
+
+        dst -= s->frame1->linesize[0];
+    }
+
+    bytestream2_skip(gb, size - (bytestream2_tell(gb) - pos));
+
+    return 0;
+}
+
+static int decode_mous(AVCodecContext *avctx,
+                       AVPacket *avpkt, unsigned size)
+{
+    RASCContext *s = avctx->priv_data;
+    GetByteContext *gb = &s->gb;
+    unsigned pos, uncompressed_size;
+    int ret;
+
+    pos = bytestream2_tell(gb);
+    bytestream2_skip(gb, 8);
+    s->cursor_w = bytestream2_get_le32(gb);
+    s->cursor_h = bytestream2_get_le32(gb);
+    bytestream2_skip(gb, 12);
+    uncompressed_size = bytestream2_get_le32(gb);
+
+    if (s->cursor_w > avctx->width ||
+        s->cursor_h > avctx->height)
+        return AVERROR_INVALIDDATA;
+
+    if (uncompressed_size < 3 * s->cursor_w * s->cursor_h)
+        return AVERROR_INVALIDDATA;
+
+    av_fast_padded_malloc(&s->cursor, &s->cursor_size, uncompressed_size);
+    if (!s->cursor)
+        return AVERROR(ENOMEM);
+
+    ret = decode_zlib(avctx, avpkt,
+                      size - (bytestream2_tell(gb) - pos),
+                      uncompressed_size);
+    if (ret < 0)
+        return ret;
+    memcpy(s->cursor, s->delta, uncompressed_size);
+
+    bytestream2_skip(gb, size - (bytestream2_tell(gb) - pos));
+
+    return 0;
+}
+
+static int decode_mpos(AVCodecContext *avctx,
+                       AVPacket *avpkt, unsigned size)
+{
+    RASCContext *s = avctx->priv_data;
+    GetByteContext *gb = &s->gb;
+    unsigned pos;
+
+    pos = bytestream2_tell(gb);
+    bytestream2_skip(gb, 8);
+    s->cursor_x = bytestream2_get_le32(gb);
+    s->cursor_y = bytestream2_get_le32(gb);
+
+    bytestream2_skip(gb, size - (bytestream2_tell(gb) - pos));
+
+    return 0;
+}
+
+static void draw_cursor(AVCodecContext *avctx)
+{
+    RASCContext *s = avctx->priv_data;
+    uint8_t *dst, *pal;
+
+    if (s->cursor_x >= avctx->width || s->cursor_y >= avctx->height)
+        return;
+
+    if (s->cursor_x + s->cursor_w > avctx->width ||
+        s->cursor_y + s->cursor_h > avctx->height)
+        return;
+
+    pal = s->frame->data[1];
+    for (int i = 0; i < s->cursor_h; i++) {
+        for (int j = 0; j < s->cursor_w; j++) {
+            int cr = s->cursor[3 * s->cursor_w * (s->cursor_h - i - 1) + 3 * j + 0];
+            int cg = s->cursor[3 * s->cursor_w * (s->cursor_h - i - 1) + 3 * j + 1];
+            int cb = s->cursor[3 * s->cursor_w * (s->cursor_h - i - 1) + 3 * j + 2];
+            int best = INT_MAX;
+            int index = 0;
+            int dist;
+
+            if (cr == s->cursor[0] && cg == s->cursor[1] && cb == s->cursor[2])
+                continue;
+
+            dst = s->frame->data[0] + s->frame->linesize[0] * (s->cursor_y + i) + (s->cursor_x + j);
+            for (int k = 0; k < 256; k++) {
+                int pr = pal[k * 4 + 0];
+                int pg = pal[k * 4 + 1];
+                int pb = pal[k * 4 + 2];
+
+                dist = FFABS(cr - pr) + FFABS(cg - pg) + FFABS(cb - pb);
+                if (dist < best) {
+                    best = dist;
+                    index = k;
+                }
+            }
+            dst[0] = index;
+        }
+    }
+}
+
+static int decode_frame(AVCodecContext *avctx,
+                        void *data, int *got_frame,
+                        AVPacket *avpkt)
+{
+    RASCContext *s = avctx->priv_data;
+    GetByteContext *gb = &s->gb;
+    int ret, intra = 0;
+    AVFrame *frame = data;
+
+    bytestream2_init(gb, avpkt->data, avpkt->size);
+
+    if (bytestream2_peek_le32(gb) == EMPT)
+        return avpkt->size;
+
+    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
+        return ret;
+    s->frame = frame;
+
+    while (bytestream2_get_bytes_left(gb) > 0) {
+        unsigned type, size = 0;
+
+        type = bytestream2_get_le32(gb);
+        if (type == KBND || type == BNDL) {
+            intra = type == KBND;
+            type = bytestream2_get_le32(gb);
+        }
+
+        size = bytestream2_get_le32(gb);
+        if (bytestream2_get_bytes_left(gb) < size)
+            return AVERROR_INVALIDDATA;
+
+        switch (type) {
+        case FINT:
+        case INIT:
+            ret = decode_fint(avctx, avpkt, size);
+            break;
+        case KFRM:
+            ret = decode_kfrm(avctx, avpkt, size);
+            break;
+        case DLTA:
+            ret = decode_dlta(avctx, avpkt, size);
+            break;
+        case MOVE:
+            ret = decode_move(avctx, avpkt, size);
+            break;
+        case MOUS:
+            ret = decode_mous(avctx, avpkt, size);
+            break;
+        case MPOS:
+            ret = decode_mpos(avctx, avpkt, size);
+            break;
+        default:
+            bytestream2_skip(gb, size);
+        }
+
+        if (ret < 0)
+            return ret;
+    }
+
+    copy_plane(avctx, s->frame2, s->frame);
+    if (!s->skip_cursor)
+        draw_cursor(avctx);
+
+    s->frame->key_frame = intra;
+    s->frame->pict_type = intra ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
+
+    *got_frame = 1;
+
+    return avpkt->size;
+}
+
+static av_cold int decode_init(AVCodecContext *avctx)
+{
+    RASCContext *s = avctx->priv_data;
+    int ret, zret;
+
+    avctx->pix_fmt = AV_PIX_FMT_PAL8;
+
+    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_EXTERNAL;
+    }
+
+    s->frame1 = av_frame_alloc();
+    s->frame2 = av_frame_alloc();
+    if (!s->frame1 || !s->frame2)
+        return AVERROR(ENOMEM);
+
+    if ((ret = ff_get_buffer(avctx, s->frame1, 0)) < 0)
+        return ret;
+
+    if ((ret = ff_get_buffer(avctx, s->frame2, 0)) < 0)
+        return ret;
+
+    clear_plane(avctx, s->frame1);
+    clear_plane(avctx, s->frame2);
+
+    return 0;
+}
+
+static av_cold int decode_close(AVCodecContext *avctx)
+{
+    RASCContext *s = avctx->priv_data;
+
+    av_freep(&s->delta);
+    s->delta_size = 0;
+    av_frame_free(&s->frame1);
+    av_frame_free(&s->frame2);
+    inflateEnd(&s->zstream);
+
+    return 0;
+}
+
+static void decode_flush(AVCodecContext *avctx)
+{
+    RASCContext *s = avctx->priv_data;
+
+    clear_plane(avctx, s->frame1);
+    clear_plane(avctx, s->frame2);
+}
+
+static const AVOption options[] = {
+{ "skip_cursor", "skip the cursor", offsetof(RASCContext, skip_cursor), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_VIDEO_PARAM },
+{ NULL },
+};
+
+static const AVClass rasc_decoder_class = {
+    .class_name = "rasc decoder",
+    .item_name  = av_default_item_name,
+    .option     = options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+AVCodec ff_rasc_decoder = {
+    .name             = "rasc",
+    .long_name        = NULL_IF_CONFIG_SMALL("RemotelyAnywhere Screen Capture"),
+    .type             = AVMEDIA_TYPE_VIDEO,
+    .id               = AV_CODEC_ID_RASC,
+    .priv_data_size   = sizeof(RASCContext),
+    .init             = decode_init,
+    .close            = decode_close,
+    .decode           = decode_frame,
+    .flush            = decode_flush,
+    .capabilities     = AV_CODEC_CAP_DR1,
+    .caps_internal    = FF_CODEC_CAP_INIT_THREADSAFE |
+                        FF_CODEC_CAP_INIT_CLEANUP,
+    .priv_class       = &rasc_decoder_class,
+};
diff --git a/libavformat/riff.c b/libavformat/riff.c
index 5f1aafe514..3907e1a9f3 100644
--- a/libavformat/riff.c
+++ b/libavformat/riff.c
@@ -474,6 +474,7 @@  const AVCodecTag ff_codec_bmp_tags[] = {
     { AV_CODEC_ID_PROSUMER,     MKTAG('B', 'T', '2', '0') },
     { AV_CODEC_ID_MWSC,         MKTAG('M', 'W', 'S', 'C') },
     { AV_CODEC_ID_WCMV,         MKTAG('W', 'C', 'M', 'V') },
+    { AV_CODEC_ID_RASC,         MKTAG('R', 'A', 'S', 'C') },
     { AV_CODEC_ID_NONE,         0 }
 };