avcodec/speedhq: Rename file to speedhqdec.c, move ff_rl_speedhq out

Renaming the decoder to speedhqdec.c makes sense since
we have an encoder in speedhqenc.c. Given that ff_rl_speedhq
is also used by the encoder, it is kept in speedhq.c
and a proper header for it is created to replace the ad-hoc
declaration in speedhqenc.c. This also allows to remove
the check for CONFIG_SPEEDHQ_DECODER, as it is always true
when speedhqdec.c is compiled.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

1 files changed, 652 insertions, 0 deletions

diff --git a/libavcodec/speedhqdec.c b/libavcodec/speedhqdec.c
new file mode 100644
index 0000000000..3dea1c3605
--- /dev/null
+++ b/libavcodec/speedhqdec.c
@@ -0,0 +1,652 @@
+/*
+ * NewTek SpeedHQ codec
+ * Copyright 2017 Steinar H. Gunderson
+ *
+ * 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
+ */
+
+/**
+ * @file
+ * NewTek SpeedHQ decoder.
+ */
+
+#define BITSTREAM_READER_LE
+
+#include "libavutil/attributes.h"
+#include "libavutil/mem_internal.h"
+
+#include "avcodec.h"
+#include "blockdsp.h"
+#include "codec_internal.h"
+#include "decode.h"
+#include "get_bits.h"
+#include "idctdsp.h"
+#include "libavutil/thread.h"
+#include "mathops.h"
+#include "mpeg12data.h"
+#include "mpeg12vlc.h"
+#include "rl.h"
+#include "speedhq.h"
+
+#define MAX_INDEX (64 - 1)
+
+/*
+ * 5 bits makes for very small tables, with no more than two lookups needed
+ * for the longest (10-bit) codes.
+ */
+#define ALPHA_VLC_BITS 5
+
+typedef struct SHQContext {
+    AVCodecContext *avctx;
+    BlockDSPContext bdsp;
+    IDCTDSPContext idsp;
+    ScanTable intra_scantable;
+    int quant_matrix[64];
+    enum { SHQ_SUBSAMPLING_420, SHQ_SUBSAMPLING_422, SHQ_SUBSAMPLING_444 }
+        subsampling;
+    enum { SHQ_NO_ALPHA, SHQ_RLE_ALPHA, SHQ_DCT_ALPHA } alpha_type;
+} SHQContext;
+
+/* NOTE: The first element is always 16, unscaled. */
+static const uint8_t unscaled_quant_matrix[64] = {
+    16, 16, 19, 22, 26, 27, 29, 34,
+    16, 16, 22, 24, 27, 29, 34, 37,
+    19, 22, 26, 27, 29, 34, 34, 38,
+    22, 22, 26, 27, 29, 34, 37, 40,
+    22, 26, 27, 29, 32, 35, 40, 48,
+    26, 27, 29, 32, 35, 40, 48, 58,
+    26, 27, 29, 34, 38, 46, 56, 69,
+    27, 29, 35, 38, 46, 56, 69, 83
+};
+
+static VLC dc_lum_vlc_le;
+static VLC dc_chroma_vlc_le;
+static VLC dc_alpha_run_vlc_le;
+static VLC dc_alpha_level_vlc_le;
+
+static inline int decode_dc_le(GetBitContext *gb, int component)
+{
+    int code, diff;
+
+    if (component == 0 || component == 3) {
+        code = get_vlc2(gb, dc_lum_vlc_le.table, DC_VLC_BITS, 2);
+    } else {
+        code = get_vlc2(gb, dc_chroma_vlc_le.table, DC_VLC_BITS, 2);
+    }
+    if (!code) {
+        diff = 0;
+    } else {
+        diff = get_xbits_le(gb, code);
+    }
+    return diff;
+}
+
+static inline int decode_alpha_block(const SHQContext *s, GetBitContext *gb, uint8_t last_alpha[16], uint8_t *dest, int linesize)
+{
+    uint8_t block[128];
+    int i = 0, x, y;
+
+    memset(block, 0, sizeof(block));
+
+    {
+        OPEN_READER(re, gb);
+
+        for ( ;; ) {
+            int run, level;
+
+            UPDATE_CACHE_LE(re, gb);
+            GET_VLC(run, re, gb, dc_alpha_run_vlc_le.table, ALPHA_VLC_BITS, 2);
+
+            if (run < 0) break;
+            i += run;
+            if (i >= 128)
+                return AVERROR_INVALIDDATA;
+
+            UPDATE_CACHE_LE(re, gb);
+            GET_VLC(level, re, gb, dc_alpha_level_vlc_le.table, ALPHA_VLC_BITS, 2);
+            block[i++] = level;
+        }
+
+        CLOSE_READER(re, gb);
+    }
+
+    for (y = 0; y < 8; y++) {
+        for (x = 0; x < 16; x++) {
+            last_alpha[x] -= block[y * 16 + x];
+        }
+        memcpy(dest, last_alpha, 16);
+        dest += linesize;
+    }
+
+    return 0;
+}
+
+static inline int decode_dct_block(const SHQContext *s, GetBitContext *gb, int last_dc[4], int component, uint8_t *dest, int linesize)
+{
+    const int *quant_matrix = s->quant_matrix;
+    const uint8_t *scantable = s->intra_scantable.permutated;
+    LOCAL_ALIGNED_32(int16_t, block, [64]);
+    int dc_offset;
+
+    s->bdsp.clear_block(block);
+
+    dc_offset = decode_dc_le(gb, component);
+    last_dc[component] -= dc_offset;  /* Note: Opposite of most codecs. */
+    block[scantable[0]] = last_dc[component];  /* quant_matrix[0] is always 16. */
+
+    /* Read AC coefficients. */
+    {
+        int i = 0;
+        OPEN_READER(re, gb);
+        for ( ;; ) {
+            int level, run;
+            UPDATE_CACHE_LE(re, gb);
+            GET_RL_VLC(level, run, re, gb, ff_rl_speedhq.rl_vlc[0],
+                       TEX_VLC_BITS, 2, 0);
+            if (level == 127) {
+                break;
+            } else if (level) {
+                i += run;
+                if (i > MAX_INDEX)
+                    return AVERROR_INVALIDDATA;
+                /* If next bit is 1, level = -level */
+                level = (level ^ SHOW_SBITS(re, gb, 1)) -
+                        SHOW_SBITS(re, gb, 1);
+                LAST_SKIP_BITS(re, gb, 1);
+            } else {
+                /* Escape. */
+#if MIN_CACHE_BITS < 6 + 6 + 12
+#error MIN_CACHE_BITS is too small for the escape code, add UPDATE_CACHE
+#endif
+                run = SHOW_UBITS(re, gb, 6) + 1;
+                SKIP_BITS(re, gb, 6);
+                level = SHOW_UBITS(re, gb, 12) - 2048;
+                LAST_SKIP_BITS(re, gb, 12);
+
+                i += run;
+                if (i > MAX_INDEX)
+                    return AVERROR_INVALIDDATA;
+            }
+
+            block[scantable[i]] = (level * quant_matrix[i]) >> 4;
+        }
+        CLOSE_READER(re, gb);
+    }
+
+    s->idsp.idct_put(dest, linesize, block);
+
+    return 0;
+}
+
+static int decode_speedhq_border(const SHQContext *s, GetBitContext *gb, AVFrame *frame, int field_number, int line_stride)
+{
+    int linesize_y  = frame->linesize[0] * line_stride;
+    int linesize_cb = frame->linesize[1] * line_stride;
+    int linesize_cr = frame->linesize[2] * line_stride;
+    int linesize_a;
+    int ret;
+
+    if (s->alpha_type != SHQ_NO_ALPHA)
+        linesize_a = frame->linesize[3] * line_stride;
+
+    for (int y = 0; y < frame->height; y += 16 * line_stride) {
+        int last_dc[4] = { 1024, 1024, 1024, 1024 };
+        uint8_t *dest_y, *dest_cb, *dest_cr, *dest_a;
+        uint8_t last_alpha[16];
+        int x = frame->width - 8;
+
+        dest_y = frame->data[0] + frame->linesize[0] * (y + field_number) + x;
+        if (s->subsampling == SHQ_SUBSAMPLING_420) {
+            dest_cb = frame->data[1] + frame->linesize[1] * (y/2 + field_number) + x / 2;
+            dest_cr = frame->data[2] + frame->linesize[2] * (y/2 + field_number) + x / 2;
+        } else {
+            av_assert2(s->subsampling == SHQ_SUBSAMPLING_422);
+            dest_cb = frame->data[1] + frame->linesize[1] * (y + field_number) + x / 2;
+            dest_cr = frame->data[2] + frame->linesize[2] * (y + field_number) + x / 2;
+        }
+        if (s->alpha_type != SHQ_NO_ALPHA) {
+            memset(last_alpha, 255, sizeof(last_alpha));
+            dest_a = frame->data[3] + frame->linesize[3] * (y + field_number) + x;
+        }
+
+        if ((ret = decode_dct_block(s, gb, last_dc, 0, dest_y, linesize_y)) < 0)
+            return ret;
+        if ((ret = decode_dct_block(s, gb, last_dc, 0, dest_y + 8, linesize_y)) < 0)
+            return ret;
+        if ((ret = decode_dct_block(s, gb, last_dc, 0, dest_y + 8 * linesize_y, linesize_y)) < 0)
+            return ret;
+        if ((ret = decode_dct_block(s, gb, last_dc, 0, dest_y + 8 * linesize_y + 8, linesize_y)) < 0)
+            return ret;
+        if ((ret = decode_dct_block(s, gb, last_dc, 1, dest_cb, linesize_cb)) < 0)
+            return ret;
+        if ((ret = decode_dct_block(s, gb, last_dc, 2, dest_cr, linesize_cr)) < 0)
+            return ret;
+
+        if (s->subsampling != SHQ_SUBSAMPLING_420) {
+            if ((ret = decode_dct_block(s, gb, last_dc, 1, dest_cb + 8 * linesize_cb, linesize_cb)) < 0)
+                return ret;
+            if ((ret = decode_dct_block(s, gb, last_dc, 2, dest_cr + 8 * linesize_cr, linesize_cr)) < 0)
+                return ret;
+        }
+
+        if (s->alpha_type == SHQ_RLE_ALPHA) {
+            /* Alpha coded using 16x8 RLE blocks. */
+            if ((ret = decode_alpha_block(s, gb, last_alpha, dest_a, linesize_a)) < 0)
+                return ret;
+            if ((ret = decode_alpha_block(s, gb, last_alpha, dest_a + 8 * linesize_a, linesize_a)) < 0)
+                return ret;
+        } else if (s->alpha_type == SHQ_DCT_ALPHA) {
+            /* Alpha encoded exactly like luma. */
+            if ((ret = decode_dct_block(s, gb, last_dc, 3, dest_a, linesize_a)) < 0)
+                return ret;
+            if ((ret = decode_dct_block(s, gb, last_dc, 3, dest_a + 8, linesize_a)) < 0)
+                return ret;
+            if ((ret = decode_dct_block(s, gb, last_dc, 3, dest_a + 8 * linesize_a, linesize_a)) < 0)
+                return ret;
+            if ((ret = decode_dct_block(s, gb, last_dc, 3, dest_a + 8 * linesize_a + 8, linesize_a)) < 0)
+                return ret;
+        }
+    }
+
+    return 0;
+}
+
+static int decode_speedhq_field(const SHQContext *s, const uint8_t *buf, int buf_size, AVFrame *frame, int field_number, int start, int end, int line_stride)
+{
+    int ret, slice_number, slice_offsets[5];
+    int linesize_y  = frame->linesize[0] * line_stride;
+    int linesize_cb = frame->linesize[1] * line_stride;
+    int linesize_cr = frame->linesize[2] * line_stride;
+    int linesize_a;
+    GetBitContext gb;
+
+    if (s->alpha_type != SHQ_NO_ALPHA)
+        linesize_a = frame->linesize[3] * line_stride;
+
+    if (end < start || end - start < 3 || end > buf_size)
+        return AVERROR_INVALIDDATA;
+
+    slice_offsets[0] = start;
+    slice_offsets[4] = end;
+    for (slice_number = 1; slice_number < 4; slice_number++) {
+        uint32_t last_offset, slice_len;
+
+        last_offset = slice_offsets[slice_number - 1];
+        slice_len = AV_RL24(buf + last_offset);
+        slice_offsets[slice_number] = last_offset + slice_len;
+
+        if (slice_len < 3 || slice_offsets[slice_number] > end - 3)
+            return AVERROR_INVALIDDATA;
+    }
+
+    for (slice_number = 0; slice_number < 4; slice_number++) {
+        uint32_t slice_begin, slice_end;
+        int x, y;
+
+        slice_begin = slice_offsets[slice_number];
+        slice_end = slice_offsets[slice_number + 1];
+
+        if ((ret = init_get_bits8(&gb, buf + slice_begin + 3, slice_end - slice_begin - 3)) < 0)
+            return ret;
+
+        for (y = slice_number * 16 * line_stride; y < frame->height; y += line_stride * 64) {
+            uint8_t *dest_y, *dest_cb, *dest_cr, *dest_a;
+            int last_dc[4] = { 1024, 1024, 1024, 1024 };
+            uint8_t last_alpha[16];
+
+            memset(last_alpha, 255, sizeof(last_alpha));
+
+            dest_y = frame->data[0] + frame->linesize[0] * (y + field_number);
+            if (s->subsampling == SHQ_SUBSAMPLING_420) {
+                dest_cb = frame->data[1] + frame->linesize[1] * (y/2 + field_number);
+                dest_cr = frame->data[2] + frame->linesize[2] * (y/2 + field_number);
+            } else {
+                dest_cb = frame->data[1] + frame->linesize[1] * (y + field_number);
+                dest_cr = frame->data[2] + frame->linesize[2] * (y + field_number);
+            }
+            if (s->alpha_type != SHQ_NO_ALPHA) {
+                dest_a = frame->data[3] + frame->linesize[3] * (y + field_number);
+            }
+
+            for (x = 0; x < frame->width - 8 * (s->subsampling != SHQ_SUBSAMPLING_444); x += 16) {
+                /* Decode the four luma blocks. */
+                if ((ret = decode_dct_block(s, &gb, last_dc, 0, dest_y, linesize_y)) < 0)
+                    return ret;
+                if ((ret = decode_dct_block(s, &gb, last_dc, 0, dest_y + 8, linesize_y)) < 0)
+                    return ret;
+                if ((ret = decode_dct_block(s, &gb, last_dc, 0, dest_y + 8 * linesize_y, linesize_y)) < 0)
+                    return ret;
+                if ((ret = decode_dct_block(s, &gb, last_dc, 0, dest_y + 8 * linesize_y + 8, linesize_y)) < 0)
+                    return ret;
+
+                /*
+                 * Decode the first chroma block. For 4:2:0, this is the only one;
+                 * for 4:2:2, it's the top block; for 4:4:4, it's the top-left block.
+                 */
+                if ((ret = decode_dct_block(s, &gb, last_dc, 1, dest_cb, linesize_cb)) < 0)
+                    return ret;
+                if ((ret = decode_dct_block(s, &gb, last_dc, 2, dest_cr, linesize_cr)) < 0)
+                    return ret;
+
+                if (s->subsampling != SHQ_SUBSAMPLING_420) {
+                    /* For 4:2:2, this is the bottom block; for 4:4:4, it's the bottom-left block. */
+                    if ((ret = decode_dct_block(s, &gb, last_dc, 1, dest_cb + 8 * linesize_cb, linesize_cb)) < 0)
+                        return ret;
+                    if ((ret = decode_dct_block(s, &gb, last_dc, 2, dest_cr + 8 * linesize_cr, linesize_cr)) < 0)
+                        return ret;
+
+                    if (s->subsampling == SHQ_SUBSAMPLING_444) {
+                        /* Top-right and bottom-right blocks. */
+                        if ((ret = decode_dct_block(s, &gb, last_dc, 1, dest_cb + 8, linesize_cb)) < 0)
+                            return ret;
+                        if ((ret = decode_dct_block(s, &gb, last_dc, 2, dest_cr + 8, linesize_cr)) < 0)
+                            return ret;
+                        if ((ret = decode_dct_block(s, &gb, last_dc, 1, dest_cb + 8 * linesize_cb + 8, linesize_cb)) < 0)
+                            return ret;
+                        if ((ret = decode_dct_block(s, &gb, last_dc, 2, dest_cr + 8 * linesize_cr + 8, linesize_cr)) < 0)
+                            return ret;
+
+                        dest_cb += 8;
+                        dest_cr += 8;
+                    }
+                }
+                dest_y += 16;
+                dest_cb += 8;
+                dest_cr += 8;
+
+                if (s->alpha_type == SHQ_RLE_ALPHA) {
+                    /* Alpha coded using 16x8 RLE blocks. */
+                    if ((ret = decode_alpha_block(s, &gb, last_alpha, dest_a, linesize_a)) < 0)
+                        return ret;
+                    if ((ret = decode_alpha_block(s, &gb, last_alpha, dest_a + 8 * linesize_a, linesize_a)) < 0)
+                        return ret;
+                    dest_a += 16;
+                } else if (s->alpha_type == SHQ_DCT_ALPHA) {
+                    /* Alpha encoded exactly like luma. */
+                    if ((ret = decode_dct_block(s, &gb, last_dc, 3, dest_a, linesize_a)) < 0)
+                        return ret;
+                    if ((ret = decode_dct_block(s, &gb, last_dc, 3, dest_a + 8, linesize_a)) < 0)
+                        return ret;
+                    if ((ret = decode_dct_block(s, &gb, last_dc, 3, dest_a + 8 * linesize_a, linesize_a)) < 0)
+                        return ret;
+                    if ((ret = decode_dct_block(s, &gb, last_dc, 3, dest_a + 8 * linesize_a + 8, linesize_a)) < 0)
+                        return ret;
+                    dest_a += 16;
+                }
+            }
+        }
+    }
+
+    if (s->subsampling != SHQ_SUBSAMPLING_444 && (frame->width & 15))
+        return decode_speedhq_border(s, &gb, frame, field_number, line_stride);
+
+    return 0;
+}
+
+static void compute_quant_matrix(int *output, int qscale)
+{
+    int i;
+    for (i = 0; i < 64; i++) output[i] = unscaled_quant_matrix[ff_zigzag_direct[i]] * qscale;
+}
+
+static int speedhq_decode_frame(AVCodecContext *avctx, AVFrame *frame,
+                                int *got_frame, AVPacket *avpkt)
+{
+    SHQContext * const s = avctx->priv_data;
+    const uint8_t *buf   = avpkt->data;
+    int buf_size         = avpkt->size;
+    uint8_t quality;
+    uint32_t second_field_offset;
+    int ret;
+
+    if (buf_size < 4 || avctx->width < 8 || avctx->width % 8 != 0)
+        return AVERROR_INVALIDDATA;
+    if (buf_size < avctx->width*avctx->height / 64 / 4)
+        return AVERROR_INVALIDDATA;
+
+    quality = buf[0];
+    if (quality >= 100) {
+        return AVERROR_INVALIDDATA;
+    }
+
+    compute_quant_matrix(s->quant_matrix, 100 - quality);
+
+    second_field_offset = AV_RL24(buf + 1);
+    if (second_field_offset >= buf_size - 3) {
+        return AVERROR_INVALIDDATA;
+    }
+
+    avctx->coded_width = FFALIGN(avctx->width, 16);
+    avctx->coded_height = FFALIGN(avctx->height, 16);
+
+    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) {
+        return ret;
+    }
+    frame->key_frame = 1;
+
+    if (second_field_offset == 4 || second_field_offset == (buf_size-4)) {
+        /*
+         * Overlapping first and second fields is used to signal
+         * encoding only a single field. In this case, "height"
+         * is ambiguous; it could mean either the height of the
+         * frame as a whole, or of the field. The former would make
+         * more sense for compatibility with legacy decoders,
+         * but this matches the convention used in NDI, which is
+         * the primary user of this trick.
+         */
+        if ((ret = decode_speedhq_field(s, buf, buf_size, frame, 0, 4, buf_size, 1)) < 0)
+            return ret;
+    } else {
+        if ((ret = decode_speedhq_field(s, buf, buf_size, frame, 0, 4, second_field_offset, 2)) < 0)
+            return ret;
+        if ((ret = decode_speedhq_field(s, buf, buf_size, frame, 1, second_field_offset, buf_size, 2)) < 0)
+            return ret;
+    }
+
+    *got_frame = 1;
+    return buf_size;
+}
+
+/*
+ * Alpha VLC. Run and level are independently coded, and would be
+ * outside the default limits for MAX_RUN/MAX_LEVEL, so we don't
+ * bother with combining them into one table.
+ */
+static av_cold void compute_alpha_vlcs(void)
+{
+    uint16_t run_code[134], level_code[266];
+    uint8_t run_bits[134], level_bits[266];
+    int16_t run_symbols[134], level_symbols[266];
+    int entry, i, sign;
+
+    /* Initialize VLC for alpha run. */
+    entry = 0;
+
+    /* 0 -> 0. */
+    run_code[entry] = 0;
+    run_bits[entry] = 1;
+    run_symbols[entry] = 0;
+    ++entry;
+
+    /* 10xx -> xx plus 1. */
+    for (i = 0; i < 4; ++i) {
+        run_code[entry] = (i << 2) | 1;
+        run_bits[entry] = 4;
+        run_symbols[entry] = i + 1;
+        ++entry;
+    }
+
+    /* 111xxxxxxx -> xxxxxxx. */
+    for (i = 0; i < 128; ++i) {
+        run_code[entry] = (i << 3) | 7;
+        run_bits[entry] = 10;
+        run_symbols[entry] = i;
+        ++entry;
+    }
+
+    /* 110 -> EOB. */
+    run_code[entry] = 3;
+    run_bits[entry] = 3;
+    run_symbols[entry] = -1;
+    ++entry;
+
+    av_assert0(entry == FF_ARRAY_ELEMS(run_code));
+
+    INIT_LE_VLC_SPARSE_STATIC(&dc_alpha_run_vlc_le, ALPHA_VLC_BITS,
+                              FF_ARRAY_ELEMS(run_code),
+                              run_bits, 1, 1,
+                              run_code, 2, 2,
+                              run_symbols, 2, 2, 160);
+
+    /* Initialize VLC for alpha level. */
+    entry = 0;
+
+    for (sign = 0; sign <= 1; ++sign) {
+        /* 1s -> -1 or +1 (depending on sign bit). */
+        level_code[entry] = (sign << 1) | 1;
+        level_bits[entry] = 2;
+        level_symbols[entry] = sign ? -1 : 1;
+        ++entry;
+
+        /* 01sxx -> xx plus 2 (2..5 or -2..-5, depending on sign bit). */
+        for (i = 0; i < 4; ++i) {
+            level_code[entry] = (i << 3) | (sign << 2) | 2;
+            level_bits[entry] = 5;
+            level_symbols[entry] = sign ? -(i + 2) : (i + 2);
+            ++entry;
+        }
+    }
+
+    /*
+     * 00xxxxxxxx -> xxxxxxxx, in two's complement. There are many codes
+     * here that would better be encoded in other ways (e.g. 0 would be
+     * encoded by increasing run, and +/- 1 would be encoded with a
+     * shorter code), but it doesn't hurt to allow everything.
+     */
+    for (i = 0; i < 256; ++i) {
+        level_code[entry] = i << 2;
+        level_bits[entry] = 10;
+        level_symbols[entry] = i;
+        ++entry;
+    }
+
+    av_assert0(entry == FF_ARRAY_ELEMS(level_code));
+
+    INIT_LE_VLC_SPARSE_STATIC(&dc_alpha_level_vlc_le, ALPHA_VLC_BITS,
+                              FF_ARRAY_ELEMS(level_code),
+                              level_bits, 1, 1,
+                              level_code, 2, 2,
+                              level_symbols, 2, 2, 288);
+}
+
+static av_cold void speedhq_static_init(void)
+{
+    /* Exactly the same as MPEG-2, except for a little-endian reader. */
+    INIT_CUSTOM_VLC_STATIC(&dc_lum_vlc_le, DC_VLC_BITS, 12,
+                           ff_mpeg12_vlc_dc_lum_bits, 1, 1,
+                           ff_mpeg12_vlc_dc_lum_code, 2, 2,
+                           INIT_VLC_OUTPUT_LE, 512);
+    INIT_CUSTOM_VLC_STATIC(&dc_chroma_vlc_le, DC_VLC_BITS, 12,
+                           ff_mpeg12_vlc_dc_chroma_bits, 1, 1,
+                           ff_mpeg12_vlc_dc_chroma_code, 2, 2,
+                           INIT_VLC_OUTPUT_LE, 514);
+
+    INIT_2D_VLC_RL(ff_rl_speedhq, 674, INIT_VLC_LE);
+
+    compute_alpha_vlcs();
+}
+
+static av_cold int speedhq_decode_init(AVCodecContext *avctx)
+{
+    int ret;
+    static AVOnce init_once = AV_ONCE_INIT;
+    SHQContext * const s = avctx->priv_data;
+
+    s->avctx = avctx;
+
+    ret = ff_thread_once(&init_once, speedhq_static_init);
+    if (ret)
+        return AVERROR_UNKNOWN;
+
+    ff_blockdsp_init(&s->bdsp);
+    ff_idctdsp_init(&s->idsp, avctx);
+    ff_init_scantable(s->idsp.idct_permutation, &s->intra_scantable, ff_zigzag_direct);
+
+    switch (avctx->codec_tag) {
+    case MKTAG('S', 'H', 'Q', '0'):
+        s->subsampling = SHQ_SUBSAMPLING_420;
+        s->alpha_type = SHQ_NO_ALPHA;
+        avctx->pix_fmt = AV_PIX_FMT_YUV420P;
+        break;
+    case MKTAG('S', 'H', 'Q', '1'):
+        s->subsampling = SHQ_SUBSAMPLING_420;
+        s->alpha_type = SHQ_RLE_ALPHA;
+        avctx->pix_fmt = AV_PIX_FMT_YUVA420P;
+        break;
+    case MKTAG('S', 'H', 'Q', '2'):
+        s->subsampling = SHQ_SUBSAMPLING_422;
+        s->alpha_type = SHQ_NO_ALPHA;
+        avctx->pix_fmt = AV_PIX_FMT_YUV422P;
+        break;
+    case MKTAG('S', 'H', 'Q', '3'):
+        s->subsampling = SHQ_SUBSAMPLING_422;
+        s->alpha_type = SHQ_RLE_ALPHA;
+        avctx->pix_fmt = AV_PIX_FMT_YUVA422P;
+        break;
+    case MKTAG('S', 'H', 'Q', '4'):
+        s->subsampling = SHQ_SUBSAMPLING_444;
+        s->alpha_type = SHQ_NO_ALPHA;
+        avctx->pix_fmt = AV_PIX_FMT_YUV444P;
+        break;
+    case MKTAG('S', 'H', 'Q', '5'):
+        s->subsampling = SHQ_SUBSAMPLING_444;
+        s->alpha_type = SHQ_RLE_ALPHA;
+        avctx->pix_fmt = AV_PIX_FMT_YUVA444P;
+        break;
+    case MKTAG('S', 'H', 'Q', '7'):
+        s->subsampling = SHQ_SUBSAMPLING_422;
+        s->alpha_type = SHQ_DCT_ALPHA;
+        avctx->pix_fmt = AV_PIX_FMT_YUVA422P;
+        break;
+    case MKTAG('S', 'H', 'Q', '9'):
+        s->subsampling = SHQ_SUBSAMPLING_444;
+        s->alpha_type = SHQ_DCT_ALPHA;
+        avctx->pix_fmt = AV_PIX_FMT_YUVA444P;
+        break;
+    default:
+        av_log(avctx, AV_LOG_ERROR, "Unknown NewTek SpeedHQ FOURCC provided (%08X)\n",
+               avctx->codec_tag);
+        return AVERROR_INVALIDDATA;
+    }
+
+    /* This matches what NDI's RGB -> Y'CbCr 4:2:2 converter uses. */
+    avctx->colorspace = AVCOL_SPC_BT470BG;
+    avctx->chroma_sample_location = AVCHROMA_LOC_CENTER;
+
+    return 0;
+}
+
+const FFCodec ff_speedhq_decoder = {
+    .p.name         = "speedhq",
+    CODEC_LONG_NAME("NewTek SpeedHQ"),
+    .p.type         = AVMEDIA_TYPE_VIDEO,
+    .p.id           = AV_CODEC_ID_SPEEDHQ,
+    .priv_data_size = sizeof(SHQContext),
+    .init           = speedhq_decode_init,
+    FF_CODEC_DECODE_CB(speedhq_decode_frame),
+    .p.capabilities = AV_CODEC_CAP_DR1,
+};