[FFmpeg-devel] [PATCH] avcodec: add Apple Pixlet decoder

Paul B Mahol onemda at gmail.com
Mon Dec 19 16:18:00 EET 2016


Signed-off-by: Paul B Mahol <onemda at gmail.com>
---
 doc/general.texi        |   1 +
 libavcodec/Makefile     |   1 +
 libavcodec/allcodecs.c  |   1 +
 libavcodec/avcodec.h    |   1 +
 libavcodec/codec_desc.c |   7 +
 libavcodec/pixlet.c     | 726 ++++++++++++++++++++++++++++++++++++++++++++++++
 libavformat/isom.c      |   2 +
 7 files changed, 739 insertions(+)
 create mode 100644 libavcodec/pixlet.c

diff --git a/doc/general.texi b/doc/general.texi
index 9ea3ba3..8f88b37 100644
--- a/doc/general.texi
+++ b/doc/general.texi
@@ -627,6 +627,7 @@ following image formats are supported:
 @item ANSI/ASCII art         @tab     @tab  X
 @item Apple Intermediate Codec @tab     @tab  X
 @item Apple MJPEG-B          @tab     @tab  X
+ at item Apple Pixlet           @tab     @tab  X
 @item Apple ProRes           @tab  X  @tab  X
 @item Apple QuickDraw        @tab     @tab  X
     @tab fourcc: qdrw
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 23e41dd..5e8eb67 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -452,6 +452,7 @@ OBJS-$(CONFIG_PGMYUV_DECODER)          += pnmdec.o pnm.o
 OBJS-$(CONFIG_PGMYUV_ENCODER)          += pnmenc.o
 OBJS-$(CONFIG_PGSSUB_DECODER)          += pgssubdec.o
 OBJS-$(CONFIG_PICTOR_DECODER)          += pictordec.o cga_data.o
+OBJS-$(CONFIG_PIXLET_DECODER)          += pixlet.o
 OBJS-$(CONFIG_PJS_DECODER)             += textdec.o ass.o
 OBJS-$(CONFIG_PNG_DECODER)             += png.o pngdec.o pngdsp.o
 OBJS-$(CONFIG_PNG_ENCODER)             += png.o pngenc.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index bbcecce..9df6390 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -281,6 +281,7 @@ void avcodec_register_all(void)
     REGISTER_ENCDEC (PGM,               pgm);
     REGISTER_ENCDEC (PGMYUV,            pgmyuv);
     REGISTER_DECODER(PICTOR,            pictor);
+    REGISTER_DECODER(PIXLET,            pixlet);
     REGISTER_ENCDEC (PNG,               png);
     REGISTER_ENCDEC (PPM,               ppm);
     REGISTER_ENCDEC (PRORES,            prores);
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 098debf..9699f70 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -412,6 +412,7 @@ enum AVCodecID {
     AV_CODEC_ID_SHEERVIDEO,
     AV_CODEC_ID_YLC,
     AV_CODEC_ID_PSD,
+    AV_CODEC_ID_PIXLET,
 
     /* 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 29ffcb9..f09d047 100644
--- a/libavcodec/codec_desc.c
+++ b/libavcodec/codec_desc.c
@@ -1339,6 +1339,13 @@ static const AVCodecDescriptor codec_descriptors[] = {
         .long_name = NULL_IF_CONFIG_SMALL("YUY2 Lossless Codec"),
         .props     = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSLESS,
     },
+    {
+        .id        = AV_CODEC_ID_PIXLET,
+        .type      = AVMEDIA_TYPE_VIDEO,
+        .name      = "pixlet",
+        .long_name = NULL_IF_CONFIG_SMALL("Apple Pixlet"),
+        .props     = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSY,
+    },
 
     /* image codecs */
     {
diff --git a/libavcodec/pixlet.c b/libavcodec/pixlet.c
new file mode 100644
index 0000000..3059d3b
--- /dev/null
+++ b/libavcodec/pixlet.c
@@ -0,0 +1,726 @@
+/*
+ * Apple Pixlet decoder
+ * Copyright (c) 2016 Paul B Mahol
+ * Copyright (c) 2015 Vittorio Giovara <vittorio.giovara 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
+ */
+
+#include <stdint.h>
+
+#include "libavutil/imgutils.h"
+#include "libavutil/intmath.h"
+#include "libavutil/opt.h"
+
+#include "avcodec.h"
+#include "bytestream.h"
+#include "get_bits.h"
+#include "unary.h"
+#include "internal.h"
+#include "thread.h"
+
+#define NB_LEVELS 4
+
+#define H 0
+#define V 1
+
+typedef struct SubBand {
+    unsigned width;
+    unsigned height;
+    unsigned size;
+    int16_t *coeffs;
+} SubBand;
+
+typedef struct LowPass {
+    unsigned width;
+    unsigned height;
+    int16_t top_left;
+    int16_t *top_row;
+    int16_t *left_column;
+    int16_t *rest;
+    int16_t *prediction;
+} LowPass;
+
+typedef struct PixletContext {
+    AVClass *class;
+
+    GetByteContext gbc;
+    GetBitContext gbit;
+
+    int levels;
+    int lowres;
+    int h, w;
+
+    int16_t *filter[2];
+    float scaling[4][2][NB_LEVELS];
+    LowPass lowpass[4];
+    SubBand band[4][NB_LEVELS * 3 + 1];
+} PixletContext;
+
+static int allocate_buffers(AVCodecContext *avctx)
+{
+    PixletContext *ctx = avctx->priv_data;
+    int i, plane;
+
+    ctx->filter[0] = av_malloc_array(ctx->h, sizeof(int16_t));
+    ctx->filter[1] = av_malloc_array(FFMAX(ctx->h, ctx->w) + 16, sizeof(int16_t));
+    if (!ctx->filter[0] || !ctx->filter[1])
+        return AVERROR(ENOMEM);
+
+    for (plane = 0; plane < 3; plane++) {
+        unsigned shift = plane > 0;
+        unsigned w = ctx->w >> shift;
+        unsigned h = ctx->h >> shift;
+
+        ctx->lowpass[plane].prediction  = av_malloc_array((w >> NB_LEVELS), sizeof(int16_t));
+        ctx->lowpass[plane].top_row     = av_malloc_array((w >> NB_LEVELS) - 1, sizeof(int16_t));
+        ctx->lowpass[plane].left_column = av_malloc_array((h >> NB_LEVELS) - 1, sizeof(int16_t));
+        ctx->lowpass[plane].rest        = av_malloc_array(((h >> NB_LEVELS) - 1) * ((w >> NB_LEVELS) - 1), sizeof(int16_t));
+        ctx->lowpass[plane].width       = w >> NB_LEVELS;
+        ctx->lowpass[plane].height      = h >> NB_LEVELS;
+        if (!ctx->lowpass[plane].prediction ||
+            !ctx->lowpass[plane].top_row ||
+            !ctx->lowpass[plane].left_column ||
+            !ctx->lowpass[plane].rest)
+            return AVERROR(ENOMEM);
+
+        ctx->band[plane][0].width  = w >> NB_LEVELS;
+        ctx->band[plane][0].height = h >> NB_LEVELS;
+        ctx->band[plane][0].size = (w >> NB_LEVELS) * (h >> NB_LEVELS);
+        ctx->band[plane][0].coeffs = av_malloc_array(ctx->band[plane][0].size, sizeof(int16_t));
+        if (!ctx->band[plane][0].coeffs)
+            return AVERROR(ENOMEM);
+
+        for (i = 0; i < NB_LEVELS * 3; i++) {
+            unsigned scale = ctx->levels - (i / 3);
+
+            ctx->band[plane][i + 1].width  = w >> scale;
+            ctx->band[plane][i + 1].height = h >> scale;
+            ctx->band[plane][i + 1].size = (w >> scale) * (h >> scale);
+            ctx->band[plane][i + 1].coeffs = av_malloc_array(ctx->band[plane][i + 1].size, sizeof(int16_t));
+            if (!ctx->band[plane][i + 1].coeffs)
+                return AVERROR(ENOMEM);
+        }
+    }
+
+    return 0;
+}
+
+static void free_buffers(AVCodecContext *avctx)
+{
+    PixletContext *ctx = avctx->priv_data;
+    int i, plane;
+
+    av_freep(&ctx->filter[0]);
+    av_freep(&ctx->filter[1]);
+
+    for (plane = 0; plane < 3; plane++) {
+        av_freep(&ctx->lowpass[plane].prediction);
+        av_freep(&ctx->lowpass[plane].top_row);
+        av_freep(&ctx->lowpass[plane].left_column);
+        av_freep(&ctx->lowpass[plane].rest);
+
+        for (i = 0; i < NB_LEVELS * 3 + 1; i++) {
+            av_freep(&ctx->band[plane][i].coeffs);
+        }
+    }
+}
+
+static av_cold int pixlet_close(AVCodecContext *avctx)
+{
+    PixletContext *ctx = avctx->priv_data;
+    free_buffers(avctx);
+    ctx->w = 0;
+    ctx->h = 0;
+    return 0;
+}
+
+static av_cold int pixlet_init(AVCodecContext *avctx)
+{
+    avctx->pix_fmt = AV_PIX_FMT_YUV420P16;
+    return 0;
+}
+
+static int read_low_coeffs(AVCodecContext *avctx, int16_t *dst, int size)
+{
+    PixletContext *ctx = avctx->priv_data;
+    GetBitContext *b = &ctx->gbit;
+    unsigned value, cnt1, nbits, j, i = 0;
+    int rlen, flag = 0, escape;
+    int64_t rparam = 3;
+
+    while (i < size) {
+        nbits = FFMIN(ff_clz((rparam >> 8) + 3) ^ 0x1F, 14);
+
+        cnt1 = get_unary(b, 0, 8);
+        if (cnt1 < 8) {
+            value = show_bits(b, nbits);
+            if (value <= 1) {
+                skip_bits(b, nbits - 1);
+                escape = ((1 << nbits) - 1) * cnt1;
+            } else {
+                skip_bits(b, nbits);
+                escape = value + ((1 << nbits) - 1) * cnt1 - 1;
+            }
+        } else {
+            escape = get_bits(b, 16);
+        }
+
+        rlen = -((escape + flag) & 1) | 1;
+        dst[i++] = rlen * ((escape + flag + 1) >> 1);
+        rparam += 120 * (escape + flag) - (120 * rparam >> 8);
+        flag = 0;
+
+        if (rparam * 4 > 0xFF || i >= size)
+            continue;
+
+        nbits = ((rparam + 8) >> 5) + (rparam ? ff_clz(rparam) : 32) - 24;
+        escape = 16383 & ((1 << nbits) - 1);
+        cnt1 = get_unary(b, 0, 8);
+        if (cnt1 > 7) {
+            rlen = get_bits(b, 16);
+        } else {
+            value = show_bits(b, nbits);
+            if (value > 1) {
+                skip_bits(b, nbits);
+                rlen = value + escape * cnt1 - 1;
+            } else {
+                if (nbits - 1 > 0)
+                    skip_bits(b, nbits - 1);
+                rlen = escape * cnt1;
+            }
+        }
+
+        if (i + rlen > size)
+            return AVERROR_INVALIDDATA;
+
+        for (j = 0; j < rlen; j++)
+            dst[i++] = 0;
+
+        rparam = 0;
+        flag = rlen < 0xFFFF ? 1 : 0;
+    }
+
+    align_get_bits(b);
+    return get_bits_count(b) >> 3;
+}
+
+static int read_high_coeffs(AVCodecContext *avctx, uint8_t *src, int16_t *dst, int size,
+                            int c, int a, int d)
+{
+    PixletContext *ctx = avctx->priv_data;
+    GetBitContext *b = &ctx->gbit;
+    unsigned cnt1, shbits, rlen, nbits, length, i = 0, j;
+    int ret, escape, pfx, xflag, yflag, flag = 0, value;
+    int64_t rparam = 3, tmp;
+
+    if ((ret = init_get_bits8(b, src, bytestream2_get_bytes_left(&ctx->gbc))) < 0)
+      return ret;
+
+    if ((a >= 0) + (a ^ (a >> 31)) - (a >> 31) != 1) {
+        nbits = 33 - ff_clz((a >= 0) + (a ^ (a >> 31)) - (a >> 31) - 1);
+        if (nbits > 16)
+            return AVERROR_INVALIDDATA;
+    } else {
+        nbits = 1;
+    }
+
+    length = 25 - nbits;
+
+    while (i < size) {
+        if (rparam >> 8 != -3) {
+            value = ff_clz((rparam >> 8) + 3) ^ 0x1F;
+        } else {
+            value = -1;
+        }
+
+        cnt1 = get_unary(b, 0, length);
+
+        if (cnt1 >= length) {
+            cnt1 = get_bits(b, nbits);
+        } else {
+            pfx = 14 + ((((int64_t)value - 14) >> 32) & (value - 14));
+            cnt1 *= (1 << pfx) - 1;
+            shbits = show_bits(b, pfx);
+            if (shbits <= 1) {
+                if (pfx - 1 > 0)
+                    skip_bits(b, pfx - 1);
+            } else {
+                skip_bits(b, pfx);
+                cnt1 += shbits - 1;
+            }
+        }
+
+        xflag = flag + cnt1;
+        yflag = xflag;
+
+        if (flag + cnt1 == 0) {
+            value = 0;
+        } else {
+            xflag &= 1u;
+            tmp = c * ((yflag + 1) >> 1) + (c >> 1);
+            value = xflag + (tmp ^ -xflag);
+        }
+
+        dst[i++] = value;
+        rparam += d * yflag - (d * rparam >> 8);
+
+        flag = 0;
+
+        if (rparam * 4 > 0xFF || i >= size)
+            continue;
+
+        pfx = ((rparam + 8) >> 5) + (rparam ? ff_clz(rparam): 32) - 24;
+        escape = 16383 & ((1 << pfx) - 1);
+        cnt1 = get_unary(b, 0, 8);
+        if (cnt1 < 8) {
+            value = show_bits(b, pfx);
+            if (value > 1) {
+                skip_bits(b, pfx);
+                rlen = value + escape * cnt1 - 1;
+            } else {
+                if (pfx - 1 > 0)
+                    skip_bits(b, pfx - 1);
+                rlen = escape * cnt1;
+            }
+        } else {
+            if (get_bits1(b))
+                value = get_bits(b, 16);
+            else
+                value = get_bits(b, 8);
+
+            rlen = value + 8 * escape;
+        }
+
+        if (rlen > 0xFFFF || i + rlen > size)
+            return AVERROR_INVALIDDATA;
+
+        for (j = 0; j < rlen; j++)
+            dst[i++] = 0;
+
+        rparam = 0;
+        flag = rlen < 0xFFFF ? 1 : 0;
+    }
+
+    align_get_bits(b);
+    return get_bits_count(b) >> 3;
+}
+
+static int read_highpass(AVCodecContext *avctx, uint8_t *ptr, int plane)
+{
+    PixletContext *ctx = avctx->priv_data;
+    int i, ret;
+
+    for (i = 0; i < ctx->levels * 3; i++) {
+        int32_t a = bytestream2_get_be32(&ctx->gbc);
+        int32_t b = bytestream2_get_be32(&ctx->gbc);
+        int32_t c = bytestream2_get_be32(&ctx->gbc);
+        int32_t d = bytestream2_get_be32(&ctx->gbc);
+        int16_t *dest = ctx->band[plane][i + 1].coeffs;
+        unsigned size = ctx->band[plane][i + 1].size;
+        uint32_t magic;
+
+        magic = bytestream2_get_be32(&ctx->gbc);
+        if (magic != 0xDEADBEEF) {
+            av_log(avctx, AV_LOG_ERROR, "wrong magic number: 0x%04x for plane %d, level %d\n", magic, plane, i);
+            return AVERROR_INVALIDDATA;
+        }
+
+        ret = read_high_coeffs(avctx, ptr + bytestream2_tell(&ctx->gbc), dest, size,
+                               c, (b >= FFABS(a)) ? b : a, d);
+        if (ret < 0) {
+            av_log(avctx, AV_LOG_ERROR, "error in highpass coefficients for plane %d, level %d\n", plane, i);
+            return ret;
+        }
+        bytestream2_skip(&ctx->gbc, ret);
+    }
+
+    return 0;
+}
+
+static void lowpass_prediction(int16_t *dst, int16_t *pred, int width, int height)
+{
+    int val, i, j;
+    int16_t *next;
+
+    memset(pred, 0, width * sizeof(*pred));
+
+    for (i = 0; i < height; i++) {
+        val = *pred + *dst;
+        *dst = val;
+        *pred = val;
+        next = dst + 2;
+        for (j = 1; j < width; j++, next++) {
+            val = pred[j] + next[-1];
+            *(next - 1) = val;
+            pred[j] = val;
+            *(next - 1) += next[-2];
+        }
+        dst = next - 1;
+    }
+}
+
+static void filter(int16_t *dest, int16_t *tmp, unsigned size, float SCALE)
+{
+    int16_t *low, *high, *ll, *lh, *hl, *hh;
+    int hsize, i, j;
+    float value;
+
+    hsize = size >> 1;
+    low = tmp + 4;
+    high = &low[hsize + 8];
+
+    if (hsize / 2 > 0) {
+        for (i = 0; i < hsize; i++) {
+            low[i]  = dest[i];
+            high[i] = dest[i + hsize];
+        }
+    }
+
+    ll = &low[hsize];
+    lh = &low[hsize];
+    hl = &high[hsize];
+    hh = hl;
+    for (i = 4, j = 2; i; i--, j++, ll--, hh++, lh++, hl--) {
+        low[i - 5] = low[j - 1];
+        lh[0] = ll[-1];
+        high[i - 5] = high[j - 2];
+        *hh = *(hl - 2);
+    }
+
+    for (i = 0; i < hsize; i++) {
+        value = low [i+1] * -0.07576144003329376f +
+                low [i  ] *  0.8586296626673486f  +
+                low [i-1] * -0.07576144003329376f +
+                high[i  ] *  0.3535533905932737f  +
+                high[i-1] *  0.3535533905932737f;
+        dest[i * 2] = av_clip_int16(value * SCALE);
+    }
+
+    for (i = 0; i < hsize; i++) {
+        value = low [i+1] * -0.01515228715813062f +
+                low [i+1] *  0.3687056777514043f  +
+                low [i  ] *  0.3687056777514043f  +
+                low [i-1] * -0.01515228715813062f +
+                high[i+1] *  0.07071067811865475f +
+                high[i  ] * -0.8485281374238569f  +
+                high[i-1] *  0.07071067811865475f;
+        dest[i * 2 + 1] = av_clip_int16(value * SCALE);
+    }
+}
+
+static void reconstruction(AVCodecContext *avctx,
+                           int16_t *dest, unsigned width, unsigned height, size_t stride, int nb_levels,
+                           float *scaling_H, float *scaling_V, int lowres)
+{
+    PixletContext *ctx = avctx->priv_data;
+    unsigned scaled_width, scaled_height;
+    float scale_H, scale_V;
+    int16_t *ptr, *tmp;
+    int i, j, k;
+
+    scaled_height = height >> nb_levels;
+    scaled_width  = width  >> nb_levels;
+    tmp = ctx->filter[0];
+
+    for (i = 0; i < nb_levels; i++) {
+        scaled_width  <<= 1;
+        scaled_height <<= 1;
+        scale_H = scaling_H[i + lowres];
+        scale_V = scaling_V[i + lowres];
+
+        ptr = dest;
+        for (j = 0; j < scaled_height; j++) {
+            filter(ptr, ctx->filter[1], scaled_width, scale_V);
+            ptr += stride;
+        }
+
+        for (j = 0; j < scaled_width; j++) {
+            ptr = dest + j;
+            for (k = 0; k < scaled_height; k++) {
+                tmp[k] = *ptr;
+                ptr += stride;
+            }
+
+            filter(tmp, ctx->filter[1], scaled_height, scale_H);
+
+            ptr = dest + j;
+            for (k = 0; k < scaled_height; k++) {
+                *ptr = tmp[k];
+                ptr += stride;
+            }
+        }
+    }
+}
+
+static void postprocess(AVFrame *frame, int plane, int w, int h, int add)
+{
+    uint16_t *dst = (uint16_t *)frame->data[plane];
+    int16_t *src  = (int16_t *)frame->data[plane];
+    int i, j;
+
+    for (j = 0; j < h; j++) {
+        for (i = 0; i < w; i++)
+            dst[i] = add + src[i];
+        dst += frame->linesize[plane] / 2;
+        src += frame->linesize[plane] / 2;
+    }
+}
+
+static int decode_plane(AVCodecContext *avctx, int plane, AVPacket *avpkt, AVFrame *frame)
+{
+    PixletContext *ctx = avctx->priv_data;
+    unsigned shift = plane > 0;
+    int16_t *ptr;
+    int i, j, ret;
+
+    for (i = ctx->levels - 1; i >= 0; i--) {
+        ctx->scaling[plane][H][i] = 1000000. / bytestream2_get_be32(&ctx->gbc);
+        ctx->scaling[plane][V][i] = 1000000. / bytestream2_get_be32(&ctx->gbc);
+    }
+
+    bytestream2_skip(&ctx->gbc, 4);
+
+    ctx->lowpass[plane].top_left = bytestream2_get_be16(&ctx->gbc);
+
+    if ((ret = init_get_bits8(&ctx->gbit, avpkt->data + bytestream2_tell(&ctx->gbc), bytestream2_get_bytes_left(&ctx->gbc))) < 0)
+        return ret;
+
+    ret = read_low_coeffs(avctx, ctx->lowpass[plane].top_row, ctx->lowpass[plane].width - 1);
+    if (ret < 0) {
+        av_log(avctx, AV_LOG_ERROR, "error in lowpass coefficients for plane %d, top row\n", plane);
+        return ret;
+    }
+
+    ret = read_low_coeffs(avctx, ctx->lowpass[plane].left_column, ctx->lowpass[plane].height - 1);
+    if (ret < 0) {
+        av_log(avctx, AV_LOG_ERROR, "error in lowpass coefficients for plane %d, left column\n", plane);
+        return ret;
+    }
+
+    ret = read_low_coeffs(avctx, ctx->lowpass[plane].rest,
+                          (ctx->lowpass[plane].width - 1) * (ctx->lowpass[plane].height - 1));
+    if (ret < 0) {
+        av_log(avctx, AV_LOG_ERROR, "error in lowpass coefficients for plane %d, rest\n", plane);
+        return ret;
+    }
+
+    bytestream2_skip(&ctx->gbc, ret);
+    if (bytestream2_get_bytes_left(&ctx->gbc) <= 0) {
+        av_log(avctx, AV_LOG_ERROR, "no bytes left\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    ret = read_highpass(avctx, avpkt->data, plane);
+    if (ret < 0)
+        return ret;
+
+    ptr = ctx->band[plane][0].coeffs;
+    ptr[0] = ctx->lowpass[plane].top_left;
+    memcpy(ptr + 1, ctx->lowpass[plane].top_row, (ctx->lowpass[plane].width - 1) * 2);
+    ptr += ctx->lowpass[plane].width;
+    for (i = 0; i < ctx->lowpass[plane].height - 1; i++) {
+        ptr[0] = ctx->lowpass[plane].left_column[i];
+        memcpy(ptr + 1, ctx->lowpass[plane].rest + i * (ctx->lowpass[plane].width - 1), (ctx->lowpass[plane].width - 1) * 2);
+        ptr += ctx->lowpass[plane].width;
+    }
+
+    lowpass_prediction(ctx->band[plane][0].coeffs, ctx->lowpass[plane].prediction,
+                       ctx->band[plane][0].width, ctx->band[plane][0].height);
+
+    for (i = 0; i < ctx->band[plane][0].height; i++) {
+        memcpy(frame->data[plane] + i * frame->linesize[plane], ctx->band[plane][0].coeffs + i * ctx->band[plane][0].width, ctx->band[plane][0].width * 2);
+        memcpy(frame->data[plane] + i * frame->linesize[plane] + ctx->band[plane][1].width * 2, ctx->band[plane][1].coeffs + i * ctx->band[plane][1].width, ctx->band[plane][1].width * 2);
+        memcpy(frame->data[plane] + (i+ctx->band[plane][2].height) * frame->linesize[plane], ctx->band[plane][2].coeffs + i * ctx->band[plane][2].width, ctx->band[plane][2].width * 2);
+        memcpy(frame->data[plane] + (i+ctx->band[plane][3].height) * frame->linesize[plane] + ctx->band[plane][3].width * 2, ctx->band[plane][3].coeffs + i * ctx->band[plane][3].width, ctx->band[plane][3].width * 2);
+    }
+
+    if (ctx->lowres < 3) {
+        for (i = 0; i < ctx->band[plane][4].height; i++) {
+            memcpy(frame->data[plane] + i * frame->linesize[plane] + ctx->band[plane][4].width * 2, ctx->band[plane][4].coeffs + i * ctx->band[plane][4].width, ctx->band[plane][4].width * 2);
+        }
+        for (i = ctx->band[plane][6].height, j = 0; i < ctx->band[plane][7].height; i++, j++) {
+            memcpy(frame->data[plane] + i * frame->linesize[plane], ctx->band[plane][5].coeffs + j * ctx->band[plane][5].width, ctx->band[plane][5].width * 2);
+            memcpy(frame->data[plane] + i * frame->linesize[plane] + ctx->band[plane][6].width * 2, ctx->band[plane][6].coeffs + j * ctx->band[plane][6].width, ctx->band[plane][6].width * 2);
+        }
+    }
+
+    if (ctx->lowres < 2) {
+        for (i = 0; i < ctx->band[plane][7].height; i++) {
+            memcpy(frame->data[plane] + i * frame->linesize[plane] + ctx->band[plane][7].width * 2, ctx->band[plane][7].coeffs + i * ctx->band[plane][7].width, ctx->band[plane][7].width * 2);
+        }
+        for (i = ctx->band[plane][9].height, j = 0; i < ctx->band[plane][10].height; i++, j++) {
+            memcpy(frame->data[plane] + i * frame->linesize[plane], ctx->band[plane][8].coeffs + j * ctx->band[plane][8].width, ctx->band[plane][8].width * 2);
+            memcpy(frame->data[plane] + i * frame->linesize[plane] + ctx->band[plane][9].width * 2, ctx->band[plane][9].coeffs + j * ctx->band[plane][9].width, ctx->band[plane][9].width * 2);
+        }
+    }
+
+    if (ctx->lowres < 1) {
+        for (i = 0, j = 0; i < ctx->band[plane][10].height; i++, j++) {
+            memcpy(frame->data[plane] + i * frame->linesize[plane] + ctx->band[plane][10].width * 2, ctx->band[plane][10].coeffs + j * ctx->band[plane][10].width, ctx->band[plane][10].width * 2);
+        }
+        for (i = ctx->band[plane][12].height, j = 0; i < ctx->band[plane][12].height * 2; i++, j++) {
+            memcpy(frame->data[plane] + i * frame->linesize[plane], ctx->band[plane][11].coeffs + j * ctx->band[plane][11].width, ctx->band[plane][11].width * 2);
+            memcpy(frame->data[plane] + i * frame->linesize[plane] + ctx->band[plane][12].width * 2, ctx->band[plane][12].coeffs + j * ctx->band[plane][12].width, ctx->band[plane][12].width * 2);
+        }
+    }
+
+    reconstruction(avctx, (int16_t *)frame->data[plane],
+                   ctx->w >> (shift + ctx->lowres), ctx->h >> (shift + ctx->lowres),
+                   frame->linesize[plane] / 2, NB_LEVELS - ctx->lowres,
+                   ctx->scaling[plane][H], ctx->scaling[plane][V], ctx->lowres);
+
+    postprocess(frame, plane, ctx->w >> (shift + ctx->lowres), ctx->h >> (shift + ctx->lowres), plane ? 0x8000 : 0x1000);
+
+    return 0;
+}
+
+static int pixlet_decode_frame(AVCodecContext *avctx, void *data,
+                               int *got_frame, AVPacket *avpkt)
+{
+    PixletContext *ctx = avctx->priv_data;
+    int i, w, h, width, height, ret, version;
+    AVFrame *p = data;
+    ThreadFrame frame = { .f = data };
+    uint32_t pktsize;
+
+    bytestream2_init(&ctx->gbc, avpkt->data, avpkt->size);
+
+    pktsize = bytestream2_get_be32(&ctx->gbc);
+    if (pktsize <= 44 || pktsize - 4 > bytestream2_get_bytes_left(&ctx->gbc)) {
+        av_log(avctx, AV_LOG_ERROR, "Invalid packet size %u.\n", pktsize);
+        return AVERROR_INVALIDDATA;
+    }
+
+    version = bytestream2_get_le32(&ctx->gbc);
+    if (version != 1)
+        avpriv_request_sample(avctx, "Version %d", version);
+
+    bytestream2_skip(&ctx->gbc, 4);
+    if (bytestream2_get_be32(&ctx->gbc) != 1)
+        return AVERROR_INVALIDDATA;
+    bytestream2_skip(&ctx->gbc, 4);
+
+    width  = bytestream2_get_be32(&ctx->gbc);
+    height = bytestream2_get_be32(&ctx->gbc);
+
+    w = FFALIGN(width,  1 << (NB_LEVELS + 1));
+    h = FFALIGN(height, 1 << (NB_LEVELS + 1));
+
+    ctx->levels = bytestream2_get_be32(&ctx->gbc);
+    if (ctx->levels != NB_LEVELS)
+        return AVERROR_INVALIDDATA;
+
+    ret = ff_set_dimensions(avctx, FF_CEIL_RSHIFT(w, ctx->lowres), FF_CEIL_RSHIFT(h, ctx->lowres));
+    if (ret < 0)
+        return ret;
+    avctx->width  = FF_CEIL_RSHIFT(width, ctx->lowres);
+    avctx->height = FF_CEIL_RSHIFT(height, ctx->lowres);
+
+    if (ctx->w != w || ctx->h != h) {
+        free_buffers(avctx);
+        ctx->w = w;
+        ctx->h = h;
+
+        ret = allocate_buffers(avctx);
+        if (ret < 0) {
+            free_buffers(avctx);
+            ctx->w = 0;
+            ctx->h = 0;
+            return ret;
+        }
+    }
+
+    bytestream2_skip(&ctx->gbc, 12);
+
+    p->pict_type = AV_PICTURE_TYPE_I;
+    p->key_frame = 1;
+
+    ret = ff_thread_get_buffer(avctx, &frame, 0);
+    if (ret < 0)
+        return ret;
+
+    for (i = 0; i < 3; i++) {
+        ret = decode_plane(avctx, i, avpkt, frame.f);
+        if (ret < 0)
+            return ret;
+        if (avctx->flags & AV_CODEC_FLAG_GRAY)
+            break;
+    }
+
+    *got_frame = 1;
+
+    return pktsize;
+}
+
+#if HAVE_THREADS
+static int pixlet_init_thread_copy(AVCodecContext *avctx)
+{
+    PixletContext *ctx = avctx->priv_data;
+    int i, plane;
+
+    ctx->filter[0] = NULL;
+    ctx->filter[1] = NULL;
+
+    for (plane = 0; plane < 3; plane++) {
+        ctx->lowpass[plane].prediction  = NULL;
+        ctx->lowpass[plane].top_row     = NULL;
+        ctx->lowpass[plane].left_column = NULL;
+        ctx->lowpass[plane].rest        = NULL;
+
+        for (i = 0; i < NB_LEVELS * 3 + 1; i++) {
+            ctx->band[plane][i].coeffs = NULL;
+        }
+    }
+    ctx->w = ctx->h = 0;
+
+    return 0;
+}
+#endif
+
+#define OFFSET(x) offsetof(PixletContext, x)
+#define VD AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_DECODING_PARAM
+
+static const AVOption options[] = {
+    { "lowres",  "Lower the decoding resolution by a power of two",
+        OFFSET(lowres), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, NB_LEVELS - 1, VD },
+    { NULL },
+};
+
+static const AVClass pixlet_class = {
+    .class_name = "pixlet",
+    .item_name  = av_default_item_name,
+    .option     = options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+AVCodec ff_pixlet_decoder = {
+    .name             = "pixlet",
+    .long_name        = NULL_IF_CONFIG_SMALL("Apple Pixlet"),
+    .type             = AVMEDIA_TYPE_VIDEO,
+    .id               = AV_CODEC_ID_PIXLET,
+    .init             = pixlet_init,
+    .init_thread_copy = ONLY_IF_THREADS_ENABLED(pixlet_init_thread_copy),
+    .close            = pixlet_close,
+    .decode           = pixlet_decode_frame,
+    .priv_data_size   = sizeof(PixletContext),
+    .priv_class       = &pixlet_class,
+    .capabilities     = AV_CODEC_CAP_DR1 |
+                        AV_CODEC_CAP_FRAME_THREADS,
+    .caps_internal    = FF_CODEC_CAP_INIT_THREADSAFE |
+                        FF_CODEC_CAP_INIT_CLEANUP,
+};
diff --git a/libavformat/isom.c b/libavformat/isom.c
index f669e0e..765a36d 100644
--- a/libavformat/isom.c
+++ b/libavformat/isom.c
@@ -292,6 +292,8 @@ const AVCodecTag ff_codec_movvideo_tags[] = {
     { AV_CODEC_ID_SHEERVIDEO, MKTAG('S', 'h', 'r', '6') },
     { AV_CODEC_ID_SHEERVIDEO, MKTAG('S', 'h', 'r', '7') },
 
+    { AV_CODEC_ID_PIXLET, MKTAG('p', 'x', 'l', 't') },
+
     { AV_CODEC_ID_NONE, 0 },
 };
 
-- 
2.5.0



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