diff --git a/Changelog b/Changelog
index 14ba8ac874..ec9de1bd85 100644
--- a/Changelog
+++ b/Changelog
@@ -17,6 +17,7 @@ version <next>:
 - APAC decoder and demuxer
 - Media 100i decoders
 - DTS to PTS reorder bsf
+- ViewQuest VQC decoder
 
 
 version 5.1:
diff --git a/doc/general_contents.texi b/doc/general_contents.texi
index b005cb6c3e..8399fcb6b7 100644
--- a/doc/general_contents.texi
+++ b/doc/general_contents.texi
@@ -1339,6 +1339,7 @@ following image formats are supported:
 @item TwinVQ (VQF flavor)    @tab     @tab  X
 @item VIMA                   @tab     @tab  X
     @tab Used in LucasArts SMUSH animations.
+@item ViewQuest VQC          @tab     @tab  X
 @item Vorbis                 @tab  E  @tab  X
     @tab A native but very primitive encoder exists.
 @item Voxware MetaSound      @tab     @tab  X
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 37b63cadc2..c7dc5da0f9 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -761,6 +761,7 @@ OBJS-$(CONFIG_VP9_QSV_ENCODER)         += qsvenc_vp9.o
 OBJS-$(CONFIG_VPLAYER_DECODER)         += textdec.o ass.o
 OBJS-$(CONFIG_VP9_V4L2M2M_DECODER)     += v4l2_m2m_dec.o
 OBJS-$(CONFIG_VQA_DECODER)             += vqavideo.o
+OBJS-$(CONFIG_VQC_DECODER)             += vqcdec.o
 OBJS-$(CONFIG_WAVPACK_DECODER)         += wavpack.o wavpackdata.o dsd.o
 OBJS-$(CONFIG_WAVPACK_ENCODER)         += wavpackdata.o wavpackenc.o
 OBJS-$(CONFIG_WBMP_DECODER)            += wbmpdec.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index cfeb01ac1c..46ad3b5a25 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -381,6 +381,7 @@ extern const FFCodec ff_vp9_decoder;
 extern const FFCodec ff_vp9_rkmpp_decoder;
 extern const FFCodec ff_vp9_v4l2m2m_decoder;
 extern const FFCodec ff_vqa_decoder;
+extern const FFCodec ff_vqc_decoder;
 extern const FFCodec ff_wbmp_decoder;
 extern const FFCodec ff_wbmp_encoder;
 extern const FFCodec ff_webp_decoder;
diff --git a/libavcodec/codec_desc.c b/libavcodec/codec_desc.c
index 93b18f9072..24a0433dba 100644
--- a/libavcodec/codec_desc.c
+++ b/libavcodec/codec_desc.c
@@ -1916,6 +1916,13 @@ static const AVCodecDescriptor codec_descriptors[] = {
         .long_name = NULL_IF_CONFIG_SMALL("Media 100i"),
         .props     = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSY,
     },
+    {
+        .id        = AV_CODEC_ID_VQC,
+        .type      = AVMEDIA_TYPE_VIDEO,
+        .name      = "vqc",
+        .long_name = NULL_IF_CONFIG_SMALL("ViewQuest VQC"),
+        .props     = AV_CODEC_PROP_LOSSY,
+    },
 
     /* various PCM "codecs" */
     {
diff --git a/libavcodec/codec_id.h b/libavcodec/codec_id.h
index 82874daaa3..f436a2b624 100644
--- a/libavcodec/codec_id.h
+++ b/libavcodec/codec_id.h
@@ -319,6 +319,7 @@ enum AVCodecID {
     AV_CODEC_ID_RADIANCE_HDR,
     AV_CODEC_ID_WBMP,
     AV_CODEC_ID_MEDIA100,
+    AV_CODEC_ID_VQC,
 
     /* various PCM "codecs" */
     AV_CODEC_ID_FIRST_AUDIO = 0x10000,     ///< A dummy id pointing at the start of audio codecs
diff --git a/libavcodec/version.h b/libavcodec/version.h
index 2206401aa8..f8abc803b6 100644
--- a/libavcodec/version.h
+++ b/libavcodec/version.h
@@ -29,8 +29,8 @@
 
 #include "version_major.h"
 
-#define LIBAVCODEC_VERSION_MINOR  50
-#define LIBAVCODEC_VERSION_MICRO 101
+#define LIBAVCODEC_VERSION_MINOR  51
+#define LIBAVCODEC_VERSION_MICRO 100
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
                                                LIBAVCODEC_VERSION_MINOR, \
diff --git a/libavcodec/vqcdec.c b/libavcodec/vqcdec.c
new file mode 100644
index 0000000000..5d1a03158c
--- /dev/null
+++ b/libavcodec/vqcdec.c
@@ -0,0 +1,430 @@
+/*
+ * ViewQuest VQC decoder
+ * Copyright (C) 2022 Peter Ross
+ *
+ * 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 "avcodec.h"
+#include "get_bits.h"
+#include "codec_internal.h"
+#include "decode.h"
+#include "libavutil/thread.h"
+
+#define VECTOR_VLC_BITS 6
+
+static const uint8_t vector_nbits[] = {
+    2, 4, 4, 4, 4, 2, 4, 4,
+    6, 6, 6, 6, 6, 6, 6, 6
+};
+
+enum {
+    SKIP_3 = 0x10,
+    SKIP_4,
+    SKIP_5,
+    SKIP_6,
+    STOP_RUN,
+    SIGNED_8BIT,
+    SIGNED_6BIT
+};
+
+/* vector symbols are signed, but returned unsigned by get_vlc2()
+   codebook indexes are cast as uint8_t in seed_codebook() to compensate */
+static const int8_t vector_symbols[] = {
+    0, SKIP_3, SKIP_4, SKIP_5, SKIP_6, STOP_RUN, 1, -1,
+    2, 3, 4, SIGNED_8BIT, -2, -3, -4, SIGNED_6BIT
+};
+
+static VLC vector_vlc;
+
+static av_cold void vqc_init_static_data(void)
+{
+    INIT_VLC_STATIC_FROM_LENGTHS(&vector_vlc, VECTOR_VLC_BITS, FF_ARRAY_ELEMS(vector_nbits),
+                             vector_nbits, 1,
+                             vector_symbols, 1, 1,
+                             0, 0, 1 << VECTOR_VLC_BITS);
+}
+
+typedef struct VqcContext {
+    AVFrame *frame;
+    uint8_t * vectors;
+    int16_t * coeff, *tmp1, *tmp2;
+    int16_t codebook[4][256];
+} VqcContext;
+
+static av_cold int vqc_decode_init(AVCodecContext * avctx)
+{
+    static AVOnce init_static_once = AV_ONCE_INIT;
+    VqcContext *s = avctx->priv_data;
+
+    s->vectors = av_malloc((avctx->width * avctx->height * 3) / 2);
+    if (!s->vectors)
+        return AVERROR(ENOMEM);
+
+    s->coeff = av_malloc_array(2 * avctx->width, sizeof(s->coeff[0]));
+    if (!s->coeff)
+        return AVERROR(ENOMEM);
+
+    s->tmp1 = av_malloc_array(avctx->width / 2, sizeof(s->tmp1[0]));
+    if (!s->tmp1)
+        return AVERROR(ENOMEM);
+
+    s->tmp2 = av_malloc_array(avctx->width / 2, sizeof(s->tmp2[0]));
+    if (!s->tmp2)
+        return AVERROR(ENOMEM);
+
+    avctx->pix_fmt = AV_PIX_FMT_YUV420P;
+    s->frame = av_frame_alloc();
+    if (!s->frame)
+        return AVERROR(ENOMEM);
+
+    ff_thread_once(&init_static_once, vqc_init_static_data);
+
+    return 0;
+}
+
+static int seed_pow1(int x)
+{
+    return x >= 1 && x <= 5 ? 1 << x : 0;
+}
+
+static int seed_pow2(int x)
+{
+    return x >= 1 && x <= 4 ? 1 << x : 1;
+}
+
+static int bias(int x, int c)
+{
+    if (x < 0)
+        return x - c;
+    else if (x > 0)
+        return x + c;
+    else
+        return 0;
+}
+
+static void seed_codebooks(VqcContext * s, const int * seed)
+{
+    int book1 = -256 * seed[3];
+    int book2 = -128 * seed[4];
+    int book3 = -128 * seed[5];
+    int book4 = -128 * seed[6];
+
+    for (int i = -128; i < 128; i++) {
+        s->codebook[0][(uint8_t)i] = book1;
+        s->codebook[1][(uint8_t)i] = bias(book2, seed[0]);
+        s->codebook[2][(uint8_t)i] = bias(book3, seed[1]);
+        s->codebook[3][(uint8_t)i] = bias(book4, seed[2]);
+
+        book1 += 2 * seed[3];
+        book2 += seed[4];
+        book3 += seed[5];
+        book4 += seed[6];
+    }
+}
+
+static void decode_vectors(VqcContext * s, const uint8_t * buf, int size, int width, int height)
+{
+    GetBitContext gb;
+    uint8_t * vectors = s->vectors;
+    uint8_t * vectors_end = s->vectors + (width * height * 3) / 2;
+
+    memset(vectors, 0, 3 * width * height / 2);
+
+    init_get_bits8(&gb, buf, size);
+
+    for (int i = 0; i < 3 * width * height / 2 / 32; i++) {
+        uint8_t * dst = vectors;
+        int symbol;
+
+        *dst++ = get_bits(&gb, 8);
+        *dst++ = get_bits(&gb, 8);
+
+        while (show_bits(&gb, 2) != 2) {
+
+            if (dst >= vectors_end - 1)
+                return;
+
+            if (!show_bits(&gb, 4)) {
+                *dst++ = 0;
+                *dst++ = 0;
+                skip_bits(&gb, 4);
+                continue;
+            }
+
+            symbol = get_vlc2(&gb, vector_vlc.table, VECTOR_VLC_BITS, 1);
+            switch(symbol) {
+            case SKIP_3: dst += 3; break;
+            case SKIP_4: dst += 4; break;
+            case SKIP_5: dst += 5; break;
+            case SKIP_6: dst += 6; break;
+            case SIGNED_8BIT: *dst++ = get_sbits(&gb, 8); break;
+            case SIGNED_6BIT: *dst++ = get_sbits(&gb, 6); break;
+            default:
+                *dst++ = symbol;
+            }
+        }
+
+        skip_bits(&gb, 2);
+        vectors += 32;
+    }
+}
+
+static void load_coeffs(VqcContext * s, const uint8_t * v, int width, int coeff_width)
+{
+    int16_t * c0     = s->coeff;
+    int16_t * c1     = s->coeff + coeff_width;
+    int16_t * c0_125 = s->coeff + (coeff_width >> 3);
+    int16_t * c1_125 = s->coeff + coeff_width + (coeff_width >> 3);
+    int16_t * c0_25  = s->coeff + (coeff_width >> 2);
+    int16_t * c1_25 =  s->coeff + coeff_width + (coeff_width >> 2);
+    int16_t * c0_5  =  s->coeff + (coeff_width >> 1);
+    int16_t * c1_5  =  s->coeff + coeff_width + (coeff_width >> 1);
+
+    for (int i = 0; i < width; i++) {
+        c0[0] = s->codebook[0][v[0]];
+        c0[1] = s->codebook[0][v[1]];
+        c0 += 2;
+
+        c1[0] = s->codebook[0][v[2]];
+        c1[1] = s->codebook[0][v[3]];
+        c1 += 2;
+
+        c0_125[0] = s->codebook[1][v[4]];
+        c0_125[1] = s->codebook[1][v[5]];
+        c0_125 += 2;
+
+        c1_125[0] = s->codebook[1][v[6]];
+        c1_125[1] = s->codebook[1][v[7]];
+        c1_125 += 2;
+
+        c0_25[0] = s->codebook[2][v[8]];
+        c0_25[1] = s->codebook[2][v[9]];
+        c0_25[2] = s->codebook[2][v[10]];
+        c0_25[3] = s->codebook[2][v[11]];
+        c0_25 += 4;
+
+        c1_25[0] = s->codebook[2][v[12]];
+        c1_25[1] = s->codebook[2][v[13]];
+        c1_25[2] = s->codebook[2][v[14]];
+        c1_25[3] = s->codebook[2][v[15]];
+        c1_25 += 4;
+
+        if (v[16] | v[17] | v[18] | v[19]) {
+            c0_5[0] = s->codebook[3][v[16]];
+            c0_5[1] = s->codebook[3][v[17]];
+            c0_5[2] = s->codebook[3][v[18]];
+            c0_5[3] = s->codebook[3][v[19]];
+        } else {
+            c0_5[0] = c0_5[1] = c0_5[2] = c0_5[3] = 0;
+        }
+
+        if (v[20] | v[21] | v[22] | v[23]) {
+            c0_5[4] = s->codebook[3][v[20]];
+            c0_5[5] = s->codebook[3][v[21]];
+            c0_5[6] = s->codebook[3][v[22]];
+            c0_5[7] = s->codebook[3][v[23]];
+        } else {
+            c0_5[4] = c0_5[5] = c0_5[6] = c0_5[7] = 0;
+        }
+        c0_5 += 8;
+
+        if (v[24] | v[25] | v[26] | v[27]) {
+            c1_5[0] = s->codebook[3][v[24]];
+            c1_5[1] = s->codebook[3][v[25]];
+            c1_5[2] = s->codebook[3][v[26]];
+            c1_5[3] = s->codebook[3][v[27]];
+        } else {
+            c1_5[0] = c1_5[1] = c1_5[2] = c1_5[3] = 0;
+        }
+
+        if (v[28] | v[29] | v[30] | v[31]) {
+            c1_5[4] = s->codebook[3][v[28]];
+            c1_5[5] = s->codebook[3][v[29]];
+            c1_5[6] = s->codebook[3][v[30]];
+            c1_5[7] = s->codebook[3][v[31]];
+        } else {
+            c1_5[4] = c1_5[5] = c1_5[6] = c1_5[7] = 0;
+        }
+        c1_5 += 8;
+
+        v += 32;
+    }
+}
+
+static void transform1(const int16_t * a, const int16_t * b, int16_t * dst, int width)
+{
+    int s0 = a[0] + (b[0] >> 1);
+
+    for (int i = 0; i < width / 2 - 1; i++) {
+        dst[i * 2] = s0;
+        s0 = a[i + 1] + ((b[i] + b[i + 1]) >> 1);
+        dst[i * 2 + 1] = ((dst[i * 2] + s0) >> 1) - 2 * b[i];
+    }
+
+    dst[width - 2] = s0;
+    dst[width - 1] = a[width / 2 - 1] + ((b[width / 2 - 2] - 2 * b[width / 2 - 1]) >> 2) - b[width / 2 - 1];
+}
+
+static uint8_t clip(int x)
+{
+    return x >= -128 ? x <= 127 ? x + 0x80 : 0x00 : 0xFF;
+}
+
+static void transform2(const int16_t * a, const int16_t * b, uint8_t * dst, int width)
+{
+    int s0 = a[0] + (b[0] >> 1);
+    int tmp;
+
+    for (int i = 0; i < width / 2 - 1; i++) {
+        dst[i * 2] = av_clip_uint8(s0 + 0x80);
+        tmp = a[i + 1] + ((b[i] + b[i + 1]) >> 1);
+        dst[i * 2 + 1] = av_clip_uint8(((tmp + s0) >> 1) - 2 * b[i] + 0x80);
+        s0 = tmp;
+    }
+
+    dst[width - 2] = clip(s0);
+    dst[width - 1] = clip(a[width / 2 - 1] + ((b[width / 2 - 2] - 2 * b[width / 2 - 1]) >> 2) - b[width / 2 - 1]);
+}
+
+static void decode_strip(VqcContext * s, uint8_t * dst, int stride, int width)
+{
+    const int16_t * coeff;
+
+    for (int i = 0; i < width; i++) {
+        int v0 = s->coeff[i];
+        int v1 = s->coeff[width + i];
+        s->coeff[i] = v0 - v1;
+        s->coeff[width + i] = v0 + v1;
+    }
+
+    coeff = s->coeff;
+
+    transform1(coeff, coeff + width / 8, s->tmp1, width / 4);
+    transform1(s->tmp1, coeff + width / 4, s->tmp2, width / 2);
+    transform2(s->tmp2, coeff + width / 2, dst, width);
+
+    coeff += width;
+    dst += stride;
+
+    transform1(coeff, coeff + width / 8, s->tmp1, width / 4);
+    transform1(s->tmp1, coeff + width / 4, s->tmp2, width / 2);
+    transform2(s->tmp2, coeff + width / 2, dst, width);
+}
+
+static void decode_frame(VqcContext * s, int width, int height)
+{
+    uint8_t * vectors = s->vectors;
+    uint8_t * y = s->frame->data[0];
+    uint8_t * u = s->frame->data[1];
+    uint8_t * v = s->frame->data[2];
+
+    for (int j = 0; j < height / 4; j++) {
+        load_coeffs(s, vectors, width / 16, width);
+        decode_strip(s, y, s->frame->linesize[0], width);
+        vectors += 2 * width;
+        y += 2 * s->frame->linesize[0];
+
+        load_coeffs(s, vectors, width / 32, width / 2);
+        decode_strip(s, u, s->frame->linesize[1], width / 2);
+        vectors += width;
+        u += 2 * s->frame->linesize[1];
+
+        load_coeffs(s, vectors, width / 16, width);
+        decode_strip(s, y, s->frame->linesize[0], width);
+        vectors += 2 * width;
+        y += 2 * s->frame->linesize[0];
+
+        load_coeffs(s, vectors, width / 32, width / 2);
+        decode_strip(s, v, s->frame->linesize[2], width / 2);
+        vectors += width;
+        v += 2 * s->frame->linesize[2];
+    }
+}
+
+static int vqc_decode_frame(AVCodecContext *avctx, AVFrame * rframe,
+                            int * got_frame, AVPacket * avpkt)
+{
+    VqcContext *s = avctx->priv_data;
+    int ret;
+    const uint8_t * buf = avpkt->data;
+    int cache, seed[7], gamma, contrast;
+
+    if (avpkt->size < 7)
+        return AVERROR_INVALIDDATA;
+
+    if ((ret = ff_reget_buffer(avctx, s->frame, 0)) < 0)
+        return ret;
+
+    av_log(avctx, AV_LOG_DEBUG, "VQC%d format\n", (buf[2] & 1) + 1);
+
+    if (((buf[0] >> 1) & 7) != 5) {
+        avpriv_request_sample(avctx, "subversion != 5\n");
+        return AVERROR_PATCHWELCOME;
+    }
+
+    cache = AV_RL24(buf + 4);
+    seed[2] = seed_pow1((cache >> 1) & 7);
+    seed[1] = seed_pow1((cache >> 4) & 7);
+    seed[0] = seed_pow1((cache >> 7) & 7);
+    seed[6] = seed_pow2((cache >> 10) & 7);
+    seed[5] = seed_pow2((cache >> 13) & 7);
+    seed[4] = seed_pow2((cache >> 16) & 7);
+    seed[3] = seed_pow2((cache >> 19) & 7);
+
+    gamma = buf[0] >> 4;
+    contrast = AV_RL16(buf + 2) >> 1;
+    if (gamma || contrast)
+        avpriv_request_sample(avctx, "gamma=0x%x, contrast=0x%x\n", gamma, contrast);
+
+    seed_codebooks(s, seed);
+    decode_vectors(s, buf + 7, avpkt->size - 7, avctx->width, avctx->height);
+    decode_frame(s, avctx->width, avctx->height);
+
+    if ((ret = av_frame_ref(rframe, s->frame)) < 0)
+        return ret;
+
+    *got_frame = 1;
+
+    return avpkt->size;
+}
+
+static av_cold int vqc_decode_end(AVCodecContext * avctx)
+{
+    VqcContext *s = avctx->priv_data;
+
+    av_freep(&s->vectors);
+    av_freep(&s->coeff);
+    av_freep(&s->tmp1);
+    av_freep(&s->tmp2);
+    av_frame_free(&s->frame);
+
+    return 0;
+}
+
+const FFCodec ff_vqc_decoder = {
+    .p.name         = "vqc",
+    CODEC_LONG_NAME("ViewQuest VQC"),
+    .p.type         = AVMEDIA_TYPE_VIDEO,
+    .p.id           = AV_CODEC_ID_VQC,
+    .priv_data_size = sizeof(VqcContext),
+    .init           = vqc_decode_init,
+    .close          = vqc_decode_end,
+    FF_CODEC_DECODE_CB(vqc_decode_frame),
+    .p.capabilities = AV_CODEC_CAP_DR1,
+    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,
+};
diff --git a/libavformat/riff.c b/libavformat/riff.c
index 0d3f322545..7319406b39 100644
--- a/libavformat/riff.c
+++ b/libavformat/riff.c
@@ -499,6 +499,8 @@ const AVCodecTag ff_codec_bmp_tags[] = {
     { AV_CODEC_ID_MVHA,         MKTAG('M', 'V', 'H', 'A') },
     { AV_CODEC_ID_MV30,         MKTAG('M', 'V', '3', '0') },
     { AV_CODEC_ID_NOTCHLC,      MKTAG('n', 'l', 'c', '1') },
+    { AV_CODEC_ID_VQC,          MKTAG('V', 'Q', 'C', '1') },
+    { AV_CODEC_ID_VQC,          MKTAG('V', 'Q', 'C', '2') },
     { AV_CODEC_ID_NONE,         0 }
 };