ffmpeg-2.8.5

git-svn-id: svn://kolibrios.org@6147 a494cfbc-eb01-0410-851d-a64ba20cac60

contrib/sdk/sources/ffmpeg/ffmpeg-2.8/libavcodec/lagarith.c

@@ -0,0 +1,752 @@
+/*
+ * Lagarith lossless decoder
+ * Copyright (c) 2009 Nathan Caldwell <saintdev (at) gmail.com>
+ *
+ * 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
+ * Lagarith lossless decoder
+ * @author Nathan Caldwell
+ */
+
+#include <inttypes.h>
+
+#include "avcodec.h"
+#include "get_bits.h"
+#include "mathops.h"
+#include "huffyuvdsp.h"
+#include "lagarithrac.h"
+#include "thread.h"
+
+enum LagarithFrameType {
+    FRAME_RAW           = 1,    /**< uncompressed */
+    FRAME_U_RGB24       = 2,    /**< unaligned RGB24 */
+    FRAME_ARITH_YUY2    = 3,    /**< arithmetic coded YUY2 */
+    FRAME_ARITH_RGB24   = 4,    /**< arithmetic coded RGB24 */
+    FRAME_SOLID_GRAY    = 5,    /**< solid grayscale color frame */
+    FRAME_SOLID_COLOR   = 6,    /**< solid non-grayscale color frame */
+    FRAME_OLD_ARITH_RGB = 7,    /**< obsolete arithmetic coded RGB (no longer encoded by upstream since version 1.1.0) */
+    FRAME_ARITH_RGBA    = 8,    /**< arithmetic coded RGBA */
+    FRAME_SOLID_RGBA    = 9,    /**< solid RGBA color frame */
+    FRAME_ARITH_YV12    = 10,   /**< arithmetic coded YV12 */
+    FRAME_REDUCED_RES   = 11,   /**< reduced resolution YV12 frame */
+};
+
+typedef struct LagarithContext {
+    AVCodecContext *avctx;
+    HuffYUVDSPContext hdsp;
+    int zeros;                  /**< number of consecutive zero bytes encountered */
+    int zeros_rem;              /**< number of zero bytes remaining to output */
+    uint8_t *rgb_planes;
+    int      rgb_planes_allocated;
+    int rgb_stride;
+} LagarithContext;
+
+/**
+ * Compute the 52bit mantissa of 1/(double)denom.
+ * This crazy format uses floats in an entropy coder and we have to match x86
+ * rounding exactly, thus ordinary floats aren't portable enough.
+ * @param denom denominator
+ * @return 52bit mantissa
+ * @see softfloat_mul
+ */
+static uint64_t softfloat_reciprocal(uint32_t denom)
+{
+    int shift = av_log2(denom - 1) + 1;
+    uint64_t ret = (1ULL << 52) / denom;
+    uint64_t err = (1ULL << 52) - ret * denom;
+    ret <<= shift;
+    err <<= shift;
+    err +=  denom / 2;
+    return ret + err / denom;
+}
+
+/**
+ * (uint32_t)(x*f), where f has the given mantissa, and exponent 0
+ * Used in combination with softfloat_reciprocal computes x/(double)denom.
+ * @param x 32bit integer factor
+ * @param mantissa mantissa of f with exponent 0
+ * @return 32bit integer value (x*f)
+ * @see softfloat_reciprocal
+ */
+static uint32_t softfloat_mul(uint32_t x, uint64_t mantissa)
+{
+    uint64_t l = x * (mantissa & 0xffffffff);
+    uint64_t h = x * (mantissa >> 32);
+    h += l >> 32;
+    l &= 0xffffffff;
+    l += 1 << av_log2(h >> 21);
+    h += l >> 32;
+    return h >> 20;
+}
+
+static uint8_t lag_calc_zero_run(int8_t x)
+{
+    return (x << 1) ^ (x >> 7);
+}
+
+static int lag_decode_prob(GetBitContext *gb, uint32_t *value)
+{
+    static const uint8_t series[] = { 1, 2, 3, 5, 8, 13, 21 };
+    int i;
+    int bit     = 0;
+    int bits    = 0;
+    int prevbit = 0;
+    unsigned val;
+
+    for (i = 0; i < 7; i++) {
+        if (prevbit && bit)
+            break;
+        prevbit = bit;
+        bit = get_bits1(gb);
+        if (bit && !prevbit)
+            bits += series[i];
+    }
+    bits--;
+    if (bits < 0 || bits > 31) {
+        *value = 0;
+        return -1;
+    } else if (bits == 0) {
+        *value = 0;
+        return 0;
+    }
+
+    val  = get_bits_long(gb, bits);
+    val |= 1U << bits;
+
+    *value = val - 1;
+
+    return 0;
+}
+
+static int lag_read_prob_header(lag_rac *rac, GetBitContext *gb)
+{
+    int i, j, scale_factor;
+    unsigned prob, cumulative_target;
+    unsigned cumul_prob = 0;
+    unsigned scaled_cumul_prob = 0;
+
+    rac->prob[0] = 0;
+    rac->prob[257] = UINT_MAX;
+    /* Read probabilities from bitstream */
+    for (i = 1; i < 257; i++) {
+        if (lag_decode_prob(gb, &rac->prob[i]) < 0) {
+            av_log(rac->avctx, AV_LOG_ERROR, "Invalid probability encountered.\n");
+            return -1;
+        }
+        if ((uint64_t)cumul_prob + rac->prob[i] > UINT_MAX) {
+            av_log(rac->avctx, AV_LOG_ERROR, "Integer overflow encountered in cumulative probability calculation.\n");
+            return -1;
+        }
+        cumul_prob += rac->prob[i];
+        if (!rac->prob[i]) {
+            if (lag_decode_prob(gb, &prob)) {
+                av_log(rac->avctx, AV_LOG_ERROR, "Invalid probability run encountered.\n");
+                return -1;
+            }
+            if (prob > 256 - i)
+                prob = 256 - i;
+            for (j = 0; j < prob; j++)
+                rac->prob[++i] = 0;
+        }
+    }
+
+    if (!cumul_prob) {
+        av_log(rac->avctx, AV_LOG_ERROR, "All probabilities are 0!\n");
+        return -1;
+    }
+
+    /* Scale probabilities so cumulative probability is an even power of 2. */
+    scale_factor = av_log2(cumul_prob);
+
+    if (cumul_prob & (cumul_prob - 1)) {
+        uint64_t mul = softfloat_reciprocal(cumul_prob);
+        for (i = 1; i <= 128; i++) {
+            rac->prob[i] = softfloat_mul(rac->prob[i], mul);
+            scaled_cumul_prob += rac->prob[i];
+        }
+        if (scaled_cumul_prob <= 0) {
+            av_log(rac->avctx, AV_LOG_ERROR, "Scaled probabilities invalid\n");
+            return AVERROR_INVALIDDATA;
+        }
+        for (; i < 257; i++) {
+            rac->prob[i] = softfloat_mul(rac->prob[i], mul);
+            scaled_cumul_prob += rac->prob[i];
+        }
+
+        scale_factor++;
+        cumulative_target = 1 << scale_factor;
+
+        if (scaled_cumul_prob > cumulative_target) {
+            av_log(rac->avctx, AV_LOG_ERROR,
+                   "Scaled probabilities are larger than target!\n");
+            return -1;
+        }
+
+        scaled_cumul_prob = cumulative_target - scaled_cumul_prob;
+
+        for (i = 1; scaled_cumul_prob; i = (i & 0x7f) + 1) {
+            if (rac->prob[i]) {
+                rac->prob[i]++;
+                scaled_cumul_prob--;
+            }
+            /* Comment from reference source:
+             * if (b & 0x80 == 0) {     // order of operations is 'wrong'; it has been left this way
+             *                          // since the compression change is negligible and fixing it
+             *                          // breaks backwards compatibility
+             *      b =- (signed int)b;
+             *      b &= 0xFF;
+             * } else {
+             *      b++;
+             *      b &= 0x7f;
+             * }
+             */
+        }
+    }
+
+    rac->scale = scale_factor;
+
+    /* Fill probability array with cumulative probability for each symbol. */
+    for (i = 1; i < 257; i++)
+        rac->prob[i] += rac->prob[i - 1];
+
+    return 0;
+}
+
+static void add_lag_median_prediction(uint8_t *dst, uint8_t *src1,
+                                      uint8_t *diff, int w, int *left,
+                                      int *left_top)
+{
+    /* This is almost identical to add_hfyu_median_pred in huffyuvdsp.h.
+     * However the &0xFF on the gradient predictor yealds incorrect output
+     * for lagarith.
+     */
+    int i;
+    uint8_t l, lt;
+
+    l  = *left;
+    lt = *left_top;
+
+    for (i = 0; i < w; i++) {
+        l = mid_pred(l, src1[i], l + src1[i] - lt) + diff[i];
+        lt = src1[i];
+        dst[i] = l;
+    }
+
+    *left     = l;
+    *left_top = lt;
+}
+
+static void lag_pred_line(LagarithContext *l, uint8_t *buf,
+                          int width, int stride, int line)
+{
+    int L, TL;
+
+    if (!line) {
+        /* Left prediction only for first line */
+        L = l->hdsp.add_hfyu_left_pred(buf, buf, width, 0);
+    } else {
+        /* Left pixel is actually prev_row[width] */
+        L = buf[width - stride - 1];
+
+        if (line == 1) {
+            /* Second line, left predict first pixel, the rest of the line is median predicted
+             * NOTE: In the case of RGB this pixel is top predicted */
+            TL = l->avctx->pix_fmt == AV_PIX_FMT_YUV420P ? buf[-stride] : L;
+        } else {
+            /* Top left is 2 rows back, last pixel */
+            TL = buf[width - (2 * stride) - 1];
+        }
+
+        add_lag_median_prediction(buf, buf - stride, buf,
+                                  width, &L, &TL);
+    }
+}
+
+static void lag_pred_line_yuy2(LagarithContext *l, uint8_t *buf,
+                               int width, int stride, int line,
+                               int is_luma)
+{
+    int L, TL;
+
+    if (!line) {
+        L= buf[0];
+        if (is_luma)
+            buf[0] = 0;
+        l->hdsp.add_hfyu_left_pred(buf, buf, width, 0);
+        if (is_luma)
+            buf[0] = L;
+        return;
+    }
+    if (line == 1) {
+        const int HEAD = is_luma ? 4 : 2;
+        int i;
+
+        L  = buf[width - stride - 1];
+        TL = buf[HEAD  - stride - 1];
+        for (i = 0; i < HEAD; i++) {
+            L += buf[i];
+            buf[i] = L;
+        }
+        for (; i < width; i++) {
+            L      = mid_pred(L & 0xFF, buf[i - stride], (L + buf[i - stride] - TL) & 0xFF) + buf[i];
+            TL     = buf[i - stride];
+            buf[i] = L;
+        }
+    } else {
+        TL = buf[width - (2 * stride) - 1];
+        L  = buf[width - stride - 1];
+        l->hdsp.add_hfyu_median_pred(buf, buf - stride, buf, width, &L, &TL);
+    }
+}
+
+static int lag_decode_line(LagarithContext *l, lag_rac *rac,
+                           uint8_t *dst, int width, int stride,
+                           int esc_count)
+{
+    int i = 0;
+    int ret = 0;
+
+    if (!esc_count)
+        esc_count = -1;
+
+    /* Output any zeros remaining from the previous run */
+handle_zeros:
+    if (l->zeros_rem) {
+        int count = FFMIN(l->zeros_rem, width - i);
+        memset(dst + i, 0, count);
+        i += count;
+        l->zeros_rem -= count;
+    }
+
+    while (i < width) {
+        dst[i] = lag_get_rac(rac);
+        ret++;
+
+        if (dst[i])
+            l->zeros = 0;
+        else
+            l->zeros++;
+
+        i++;
+        if (l->zeros == esc_count) {
+            int index = lag_get_rac(rac);
+            ret++;
+
+            l->zeros = 0;
+
+            l->zeros_rem = lag_calc_zero_run(index);
+            goto handle_zeros;
+        }
+    }
+    return ret;
+}
+
+static int lag_decode_zero_run_line(LagarithContext *l, uint8_t *dst,
+                                    const uint8_t *src, const uint8_t *src_end,
+                                    int width, int esc_count)
+{
+    int i = 0;
+    int count;
+    uint8_t zero_run = 0;
+    const uint8_t *src_start = src;
+    uint8_t mask1 = -(esc_count < 2);
+    uint8_t mask2 = -(esc_count < 3);
+    uint8_t *end = dst + (width - 2);
+
+    avpriv_request_sample(l->avctx, "zero_run_line");
+
+    memset(dst, 0, width);
+
+output_zeros:
+    if (l->zeros_rem) {
+        count = FFMIN(l->zeros_rem, width - i);
+        if (end - dst < count) {
+            av_log(l->avctx, AV_LOG_ERROR, "Too many zeros remaining.\n");
+            return AVERROR_INVALIDDATA;
+        }
+
+        memset(dst, 0, count);
+        l->zeros_rem -= count;
+        dst += count;
+    }
+
+    while (dst < end) {
+        i = 0;
+        while (!zero_run && dst + i < end) {
+            i++;
+            if (i+2 >= src_end - src)
+                return AVERROR_INVALIDDATA;
+            zero_run =
+                !(src[i] | (src[i + 1] & mask1) | (src[i + 2] & mask2));
+        }
+        if (zero_run) {
+            zero_run = 0;
+            i += esc_count;
+            memcpy(dst, src, i);
+            dst += i;
+            l->zeros_rem = lag_calc_zero_run(src[i]);
+
+            src += i + 1;
+            goto output_zeros;
+        } else {
+            memcpy(dst, src, i);
+            src += i;
+            dst += i;
+        }
+    }
+    return  src - src_start;
+}
+
+
+
+static int lag_decode_arith_plane(LagarithContext *l, uint8_t *dst,
+                                  int width, int height, int stride,
+                                  const uint8_t *src, int src_size)
+{
+    int i = 0;
+    int read = 0;
+    uint32_t length;
+    uint32_t offset = 1;
+    int esc_count;
+    GetBitContext gb;
+    lag_rac rac;
+    const uint8_t *src_end = src + src_size;
+    int ret;
+
+    rac.avctx = l->avctx;
+    l->zeros = 0;
+
+    if(src_size < 2)
+        return AVERROR_INVALIDDATA;
+
+    esc_count = src[0];
+    if (esc_count < 4) {
+        length = width * height;
+        if(src_size < 5)
+            return AVERROR_INVALIDDATA;
+        if (esc_count && AV_RL32(src + 1) < length) {
+            length = AV_RL32(src + 1);
+            offset += 4;
+        }
+
+        if ((ret = init_get_bits8(&gb, src + offset, src_size - offset)) < 0)
+            return ret;
+
+        if (lag_read_prob_header(&rac, &gb) < 0)
+            return -1;
+
+        ff_lag_rac_init(&rac, &gb, length - stride);
+
+        for (i = 0; i < height; i++)
+            read += lag_decode_line(l, &rac, dst + (i * stride), width,
+                                    stride, esc_count);
+
+        if (read > length)
+            av_log(l->avctx, AV_LOG_WARNING,
+                   "Output more bytes than length (%d of %"PRIu32")\n", read,
+                   length);
+    } else if (esc_count < 8) {
+        esc_count -= 4;
+        src ++;
+        src_size --;
+        if (esc_count > 0) {
+            /* Zero run coding only, no range coding. */
+            for (i = 0; i < height; i++) {
+                int res = lag_decode_zero_run_line(l, dst + (i * stride), src,
+                                                   src_end, width, esc_count);
+                if (res < 0)
+                    return res;
+                src += res;
+            }
+        } else {
+            if (src_size < width * height)
+                return AVERROR_INVALIDDATA; // buffer not big enough
+            /* Plane is stored uncompressed */
+            for (i = 0; i < height; i++) {
+                memcpy(dst + (i * stride), src, width);
+                src += width;
+            }
+        }
+    } else if (esc_count == 0xff) {
+        /* Plane is a solid run of given value */
+        for (i = 0; i < height; i++)
+            memset(dst + i * stride, src[1], width);
+        /* Do not apply prediction.
+           Note: memset to 0 above, setting first value to src[1]
+           and applying prediction gives the same result. */
+        return 0;
+    } else {
+        av_log(l->avctx, AV_LOG_ERROR,
+               "Invalid zero run escape code! (%#x)\n", esc_count);
+        return -1;
+    }
+
+    if (l->avctx->pix_fmt != AV_PIX_FMT_YUV422P) {
+        for (i = 0; i < height; i++) {
+            lag_pred_line(l, dst, width, stride, i);
+            dst += stride;
+        }
+    } else {
+        for (i = 0; i < height; i++) {
+            lag_pred_line_yuy2(l, dst, width, stride, i,
+                               width == l->avctx->width);
+            dst += stride;
+        }
+    }
+
+    return 0;
+}
+
+/**
+ * Decode a frame.
+ * @param avctx codec context
+ * @param data output AVFrame
+ * @param data_size size of output data or 0 if no picture is returned
+ * @param avpkt input packet
+ * @return number of consumed bytes on success or negative if decode fails
+ */
+static int lag_decode_frame(AVCodecContext *avctx,
+                            void *data, int *got_frame, AVPacket *avpkt)
+{
+    const uint8_t *buf = avpkt->data;
+    unsigned int buf_size = avpkt->size;
+    LagarithContext *l = avctx->priv_data;
+    ThreadFrame frame = { .f = data };
+    AVFrame *const p  = data;
+    uint8_t frametype = 0;
+    uint32_t offset_gu = 0, offset_bv = 0, offset_ry = 9;
+    uint32_t offs[4];
+    uint8_t *srcs[4], *dst;
+    int i, j, planes = 3;
+    int ret;
+
+    p->key_frame = 1;
+
+    frametype = buf[0];
+
+    offset_gu = AV_RL32(buf + 1);
+    offset_bv = AV_RL32(buf + 5);
+
+    switch (frametype) {
+    case FRAME_SOLID_RGBA:
+        avctx->pix_fmt = AV_PIX_FMT_RGB32;
+    case FRAME_SOLID_GRAY:
+        if (frametype == FRAME_SOLID_GRAY)
+            if (avctx->bits_per_coded_sample == 24) {
+                avctx->pix_fmt = AV_PIX_FMT_RGB24;
+            } else {
+                avctx->pix_fmt = AV_PIX_FMT_0RGB32;
+                planes = 4;
+            }
+
+        if ((ret = ff_thread_get_buffer(avctx, &frame, 0)) < 0)
+            return ret;
+
+        dst = p->data[0];
+        if (frametype == FRAME_SOLID_RGBA) {
+        for (j = 0; j < avctx->height; j++) {
+            for (i = 0; i < avctx->width; i++)
+                AV_WN32(dst + i * 4, offset_gu);
+            dst += p->linesize[0];
+        }
+        } else {
+            for (j = 0; j < avctx->height; j++) {
+                memset(dst, buf[1], avctx->width * planes);
+                dst += p->linesize[0];
+            }
+        }
+        break;
+    case FRAME_SOLID_COLOR:
+        if (avctx->bits_per_coded_sample == 24) {
+            avctx->pix_fmt = AV_PIX_FMT_RGB24;
+        } else {
+            avctx->pix_fmt = AV_PIX_FMT_RGB32;
+            offset_gu |= 0xFFU << 24;
+        }
+
+        if ((ret = ff_thread_get_buffer(avctx, &frame,0)) < 0)
+            return ret;
+
+        dst = p->data[0];
+        for (j = 0; j < avctx->height; j++) {
+            for (i = 0; i < avctx->width; i++)
+                if (avctx->bits_per_coded_sample == 24) {
+                    AV_WB24(dst + i * 3, offset_gu);
+                } else {
+                    AV_WN32(dst + i * 4, offset_gu);
+                }
+            dst += p->linesize[0];
+        }
+        break;
+    case FRAME_ARITH_RGBA:
+        avctx->pix_fmt = AV_PIX_FMT_RGB32;
+        planes = 4;
+        offset_ry += 4;
+        offs[3] = AV_RL32(buf + 9);
+    case FRAME_ARITH_RGB24:
+    case FRAME_U_RGB24:
+        if (frametype == FRAME_ARITH_RGB24 || frametype == FRAME_U_RGB24)
+            avctx->pix_fmt = AV_PIX_FMT_RGB24;
+
+        if ((ret = ff_thread_get_buffer(avctx, &frame, 0)) < 0)
+            return ret;
+
+        offs[0] = offset_bv;
+        offs[1] = offset_gu;
+        offs[2] = offset_ry;
+
+        l->rgb_stride = FFALIGN(avctx->width, 16);
+        av_fast_malloc(&l->rgb_planes, &l->rgb_planes_allocated,
+                       l->rgb_stride * avctx->height * planes + 1);
+        if (!l->rgb_planes) {
+            av_log(avctx, AV_LOG_ERROR, "cannot allocate temporary buffer\n");
+            return AVERROR(ENOMEM);
+        }
+        for (i = 0; i < planes; i++)
+            srcs[i] = l->rgb_planes + (i + 1) * l->rgb_stride * avctx->height - l->rgb_stride;
+        for (i = 0; i < planes; i++)
+            if (buf_size <= offs[i]) {
+                av_log(avctx, AV_LOG_ERROR,
+                        "Invalid frame offsets\n");
+                return AVERROR_INVALIDDATA;
+            }
+
+        for (i = 0; i < planes; i++)
+            lag_decode_arith_plane(l, srcs[i],
+                                   avctx->width, avctx->height,
+                                   -l->rgb_stride, buf + offs[i],
+                                   buf_size - offs[i]);
+        dst = p->data[0];
+        for (i = 0; i < planes; i++)
+            srcs[i] = l->rgb_planes + i * l->rgb_stride * avctx->height;
+        for (j = 0; j < avctx->height; j++) {
+            for (i = 0; i < avctx->width; i++) {
+                uint8_t r, g, b, a;
+                r = srcs[0][i];
+                g = srcs[1][i];
+                b = srcs[2][i];
+                r += g;
+                b += g;
+                if (frametype == FRAME_ARITH_RGBA) {
+                    a = srcs[3][i];
+                    AV_WN32(dst + i * 4, MKBETAG(a, r, g, b));
+                } else {
+                    dst[i * 3 + 0] = r;
+                    dst[i * 3 + 1] = g;
+                    dst[i * 3 + 2] = b;
+                }
+            }
+            dst += p->linesize[0];
+            for (i = 0; i < planes; i++)
+                srcs[i] += l->rgb_stride;
+        }
+        break;
+    case FRAME_ARITH_YUY2:
+        avctx->pix_fmt = AV_PIX_FMT_YUV422P;
+
+        if ((ret = ff_thread_get_buffer(avctx, &frame, 0)) < 0)
+            return ret;
+
+        if (offset_ry >= buf_size ||
+            offset_gu >= buf_size ||
+            offset_bv >= buf_size) {
+            av_log(avctx, AV_LOG_ERROR,
+                   "Invalid frame offsets\n");
+            return AVERROR_INVALIDDATA;
+        }
+
+        lag_decode_arith_plane(l, p->data[0], avctx->width, avctx->height,
+                               p->linesize[0], buf + offset_ry,
+                               buf_size - offset_ry);
+        lag_decode_arith_plane(l, p->data[1], (avctx->width + 1) / 2,
+                               avctx->height, p->linesize[1],
+                               buf + offset_gu, buf_size - offset_gu);
+        lag_decode_arith_plane(l, p->data[2], (avctx->width + 1) / 2,
+                               avctx->height, p->linesize[2],
+                               buf + offset_bv, buf_size - offset_bv);
+        break;
+    case FRAME_ARITH_YV12:
+        avctx->pix_fmt = AV_PIX_FMT_YUV420P;
+
+        if ((ret = ff_thread_get_buffer(avctx, &frame, 0)) < 0)
+            return ret;
+        if (buf_size <= offset_ry || buf_size <= offset_gu || buf_size <= offset_bv) {
+            return AVERROR_INVALIDDATA;
+        }
+
+        if (offset_ry >= buf_size ||
+            offset_gu >= buf_size ||
+            offset_bv >= buf_size) {
+            av_log(avctx, AV_LOG_ERROR,
+                   "Invalid frame offsets\n");
+            return AVERROR_INVALIDDATA;
+        }
+
+        lag_decode_arith_plane(l, p->data[0], avctx->width, avctx->height,
+                               p->linesize[0], buf + offset_ry,
+                               buf_size - offset_ry);
+        lag_decode_arith_plane(l, p->data[2], (avctx->width + 1) / 2,
+                               (avctx->height + 1) / 2, p->linesize[2],
+                               buf + offset_gu, buf_size - offset_gu);
+        lag_decode_arith_plane(l, p->data[1], (avctx->width + 1) / 2,
+                               (avctx->height + 1) / 2, p->linesize[1],
+                               buf + offset_bv, buf_size - offset_bv);
+        break;
+    default:
+        av_log(avctx, AV_LOG_ERROR,
+               "Unsupported Lagarith frame type: %#"PRIx8"\n", frametype);
+        return AVERROR_PATCHWELCOME;
+    }
+
+    *got_frame = 1;
+
+    return buf_size;
+}
+
+static av_cold int lag_decode_init(AVCodecContext *avctx)
+{
+    LagarithContext *l = avctx->priv_data;
+    l->avctx = avctx;
+
+    ff_huffyuvdsp_init(&l->hdsp);
+
+    return 0;
+}
+
+static av_cold int lag_decode_end(AVCodecContext *avctx)
+{
+    LagarithContext *l = avctx->priv_data;
+
+    av_freep(&l->rgb_planes);
+
+    return 0;
+}
+
+AVCodec ff_lagarith_decoder = {
+    .name           = "lagarith",
+    .long_name      = NULL_IF_CONFIG_SMALL("Lagarith lossless"),
+    .type           = AVMEDIA_TYPE_VIDEO,
+    .id             = AV_CODEC_ID_LAGARITH,
+    .priv_data_size = sizeof(LagarithContext),
+    .init           = lag_decode_init,
+    .close          = lag_decode_end,
+    .decode         = lag_decode_frame,
+    .capabilities   = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS,
+};