avcodec: add SMC encoder

6 files changed, 569 insertions, 3 deletions

diff --git a/Changelog b/Changelog
index 03b750948f..5a5b50eb66 100644
--- a/Changelog
+++ b/Changelog
@@ -10,6 +10,7 @@ version <next>:
 - Concatf protocol
 - afwtdn audio filter
 - audio and video segment filters
+- Apple Graphics (SMC) encoder
 
 
 version 4.4:
diff --git a/doc/general_contents.texi b/doc/general_contents.texi
index f3f4feab70..edc047e539 100644
--- a/doc/general_contents.texi
+++ b/doc/general_contents.texi
@@ -1018,7 +1018,7 @@ following image formats are supported:
 @item QuickTime 8BPS video   @tab     @tab  X
 @item QuickTime Animation (RLE) video  @tab  X  @tab  X
     @tab fourcc: 'rle '
-@item QuickTime Graphics (SMC)  @tab     @tab  X
+@item QuickTime Graphics (SMC)  @tab  X  @tab  X
     @tab fourcc: 'smc '
 @item QuickTime video (RPZA) @tab  X  @tab  X
     @tab fourcc: rpza
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 9a6adb9903..0dc564f5dc 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -621,6 +621,7 @@ OBJS-$(CONFIG_SIMBIOSIS_IMX_DECODER)   += imx.o
 OBJS-$(CONFIG_SMACKAUD_DECODER)        += smacker.o
 OBJS-$(CONFIG_SMACKER_DECODER)         += smacker.o
 OBJS-$(CONFIG_SMC_DECODER)             += smc.o
+OBJS-$(CONFIG_SMC_ENCODER)             += smcenc.o
 OBJS-$(CONFIG_SNOW_DECODER)            += snowdec.o snow.o snow_dwt.o
 OBJS-$(CONFIG_SNOW_ENCODER)            += snowenc.o snow.o snow_dwt.o             \
                                           h263.o h263data.o ituh263enc.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index 71bc21aa05..c087b91148 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -299,6 +299,7 @@ extern const AVCodec ff_sgirle_decoder;
 extern const AVCodec ff_sheervideo_decoder;
 extern const AVCodec ff_simbiosis_imx_decoder;
 extern const AVCodec ff_smacker_decoder;
+extern const AVCodec ff_smc_encoder;
 extern const AVCodec ff_smc_decoder;
 extern const AVCodec ff_smvjpeg_decoder;
 extern const AVCodec ff_snow_encoder;
diff --git a/libavcodec/smcenc.c b/libavcodec/smcenc.c
new file mode 100644
index 0000000000..5b0035b244
--- /dev/null
+++ b/libavcodec/smcenc.c
@@ -0,0 +1,563 @@
+/*
+ * QuickTime Graphics (SMC) Video Encoder
+ * Copyright (c) 2021 The FFmpeg project
+ *
+ * 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 smcenc.c
+ * QT SMC Video Encoder by Paul B. Mahol
+ */
+
+#include "libavutil/common.h"
+
+#include "avcodec.h"
+#include "encode.h"
+#include "internal.h"
+#include "bytestream.h"
+
+#define CPAIR 2
+#define CQUAD 4
+#define COCTET 8
+
+#define COLORS_PER_TABLE 256
+
+typedef struct SMCContext {
+    AVFrame *prev_frame;    // buffer for previous source frame
+    PutByteContext pb;
+
+    uint8_t mono_value;
+    int nb_distinct;
+    int next_nb_distinct;
+    uint8_t distinct_values[16];
+    uint8_t next_distinct_values[16];
+
+    uint8_t color_pairs[COLORS_PER_TABLE][CPAIR];
+    uint8_t color_quads[COLORS_PER_TABLE][CQUAD];
+    uint8_t color_octets[COLORS_PER_TABLE][COCTET];
+
+    int key_frame;
+} SMCContext;
+
+#define ADVANCE_BLOCK(pixel_ptr, row_ptr, nb_blocks) \
+{ \
+    for (int block = 0; block < nb_blocks && pixel_ptr && row_ptr; block++) { \
+        pixel_ptr += 4; \
+        if (pixel_ptr - row_ptr >= width) \
+        { \
+            row_ptr += stride * 4; \
+            pixel_ptr = row_ptr; \
+        } \
+    } \
+}
+
+static int smc_cmp_values(const void *a, const void *b)
+{
+    const uint8_t *aa = a, *bb = b;
+
+    return FFDIFFSIGN(aa[0], bb[0]);
+}
+
+static int count_distinct_items(const uint8_t *block_values,
+                                uint8_t *distinct_values,
+                                int size)
+{
+    int n = 1;
+
+    distinct_values[0] = block_values[0];
+    for (int i = 1; i < size; i++) {
+        if (block_values[i] != block_values[i-1]) {
+            distinct_values[n] = block_values[i];
+            n++;
+        }
+    }
+
+    return n;
+}
+
+#define CACHE_PAIR(x) \
+    (s->color_pairs[i][0] == distinct_values[x] || \
+     s->color_pairs[i][1] == distinct_values[x])
+
+#define CACHE_QUAD(x) \
+    (s->color_quads[i][0] == distinct_values[x] || \
+     s->color_quads[i][1] == distinct_values[x] || \
+     s->color_quads[i][2] == distinct_values[x] || \
+     s->color_quads[i][3] == distinct_values[x])
+
+#define CACHE_OCTET(x) \
+    (s->color_octets[i][0] == distinct_values[x] || \
+     s->color_octets[i][1] == distinct_values[x] || \
+     s->color_octets[i][2] == distinct_values[x] || \
+     s->color_octets[i][3] == distinct_values[x] || \
+     s->color_octets[i][4] == distinct_values[x] || \
+     s->color_octets[i][5] == distinct_values[x] || \
+     s->color_octets[i][6] == distinct_values[x] || \
+     s->color_octets[i][7] == distinct_values[x])
+
+static void smc_encode_stream(SMCContext *s, const AVFrame *frame)
+{
+    PutByteContext *pb = &s->pb;
+    const uint8_t *src_pixels = (const uint8_t *)frame->data[0];
+    const int stride = frame->linesize[0];
+    const uint8_t *prev_pixels = (const uint8_t *)s->prev_frame->data[0];
+    uint8_t *distinct_values = s->distinct_values;
+    const uint8_t *pixel_ptr, *row_ptr;
+    const int width = frame->width;
+    uint8_t block_values[16];
+    int block_counter = 0;
+    int color_pair_index = 0;
+    int color_quad_index = 0;
+    int color_octet_index = 0;
+    int color_table_index;  /* indexes to color pair, quad, or octet tables */
+    int total_blocks;
+
+    memset(s->color_pairs, 0, sizeof(s->color_pairs));
+    memset(s->color_quads, 0, sizeof(s->color_quads));
+    memset(s->color_octets, 0, sizeof(s->color_octets));
+
+    /* Number of 4x4 blocks in frame. */
+    total_blocks = ((frame->width + 3) / 4) * ((frame->height + 3) / 4);
+
+    pixel_ptr = row_ptr = src_pixels;
+
+    while (block_counter < total_blocks) {
+        const uint8_t *xpixel_ptr = pixel_ptr;
+        const uint8_t *xrow_ptr = row_ptr;
+        int intra_skip_blocks = 0;
+        int inter_skip_blocks = 0;
+        int coded_distinct = 0;
+        int coded_blocks = 0;
+        int cache_index;
+        int distinct = 0;
+        int blocks = 0;
+
+        while (prev_pixels && s->key_frame == 0 && block_counter + inter_skip_blocks < total_blocks) {
+            int compare = 0;
+
+            for (int y = 0; y < 4; y++) {
+                const ptrdiff_t offset = pixel_ptr - src_pixels;
+                const uint8_t *prev_pixel_ptr = prev_pixels + offset;
+
+                compare |= memcmp(prev_pixel_ptr + y * stride, pixel_ptr + y * stride, 4);
+                if (compare)
+                    break;
+            }
+
+            if (compare)
+                break;
+
+            if (inter_skip_blocks >= 256)
+                break;
+            inter_skip_blocks++;
+
+            ADVANCE_BLOCK(pixel_ptr, row_ptr, 1)
+        }
+
+        pixel_ptr = xpixel_ptr;
+        row_ptr = xrow_ptr;
+
+        while (block_counter > 0 && block_counter + intra_skip_blocks < total_blocks) {
+            const ptrdiff_t offset = pixel_ptr - src_pixels;
+            const int sy = offset / stride;
+            const int sx = offset % stride;
+            const int ny = sx < 4 ? sy - 4 : sy;
+            const int nx = sx < 4 ? width - 4 : sx - 4;
+            const uint8_t *old_pixel_ptr = src_pixels + nx + ny * stride;
+            int compare = 0;
+
+            for (int y = 0; y < 4; y++) {
+                compare |= memcmp(old_pixel_ptr + y * stride, pixel_ptr + y * stride, 4);
+                if (compare)
+                    break;
+            }
+
+            if (compare)
+                break;
+
+            if (intra_skip_blocks >= 256)
+                break;
+            intra_skip_blocks++;
+            ADVANCE_BLOCK(pixel_ptr, row_ptr, 1)
+        }
+
+        pixel_ptr = xpixel_ptr;
+        row_ptr = xrow_ptr;
+
+        while (block_counter + coded_blocks < total_blocks && coded_blocks < 256) {
+            for (int y = 0; y < 4; y++)
+                memcpy(block_values + y * 4, pixel_ptr + y * stride, 4);
+
+            qsort(block_values, 16, sizeof(block_values[0]), smc_cmp_values);
+            s->next_nb_distinct = count_distinct_items(block_values, s->next_distinct_values, 16);
+            if (coded_blocks == 0) {
+                memcpy(distinct_values, s->next_distinct_values, sizeof(s->distinct_values));
+                s->nb_distinct = s->next_nb_distinct;
+            } else {
+                if (s->next_nb_distinct != s->nb_distinct ||
+                    memcmp(distinct_values, s->next_distinct_values, s->nb_distinct)) {
+                    break;
+                }
+            }
+            s->mono_value = block_values[0];
+
+            coded_distinct = s->nb_distinct;
+            ADVANCE_BLOCK(pixel_ptr, row_ptr, 1)
+            coded_blocks++;
+            if (coded_distinct > 1 && coded_blocks >= 16)
+                break;
+        }
+
+        pixel_ptr = xpixel_ptr;
+        row_ptr = xrow_ptr;
+
+        blocks = coded_blocks;
+        distinct = coded_distinct;
+
+        if (intra_skip_blocks > 0 && intra_skip_blocks >= inter_skip_blocks &&
+            intra_skip_blocks > 0) {
+            distinct = 17;
+            blocks = intra_skip_blocks;
+        }
+
+        if (intra_skip_blocks > 16 && intra_skip_blocks >= inter_skip_blocks &&
+            intra_skip_blocks > 0) {
+            distinct = 18;
+            blocks = intra_skip_blocks;
+        }
+
+        if (inter_skip_blocks > 0 && inter_skip_blocks > intra_skip_blocks &&
+            inter_skip_blocks > 0) {
+            distinct = 19;
+            blocks = inter_skip_blocks;
+        }
+
+        if (inter_skip_blocks > 16 && inter_skip_blocks > intra_skip_blocks &&
+            inter_skip_blocks > 0) {
+            distinct = 20;
+            blocks = inter_skip_blocks;
+        }
+
+        switch (distinct) {
+        case 1:
+            if (blocks <= 16) {
+                bytestream2_put_byte(pb, 0x60 | (blocks - 1));
+            } else {
+                bytestream2_put_byte(pb, 0x70);
+                bytestream2_put_byte(pb, blocks - 1);
+            }
+            bytestream2_put_byte(pb, s->mono_value);
+            ADVANCE_BLOCK(pixel_ptr, row_ptr, blocks)
+            break;
+        case 2:
+            cache_index = -1;
+            for (int i = 0; i < COLORS_PER_TABLE; i++) {
+                if (CACHE_PAIR(0) &&
+                    CACHE_PAIR(1)) {
+                    cache_index = i;
+                    break;
+                }
+            }
+
+            if (cache_index >= 0) {
+                bytestream2_put_byte(pb, 0x90 | (blocks - 1));
+                bytestream2_put_byte(pb, cache_index);
+                color_table_index = cache_index;
+            } else {
+                bytestream2_put_byte(pb, 0x80 | (blocks - 1));
+
+                color_table_index = color_pair_index;
+                for (int i = 0; i < CPAIR; i++) {
+                    s->color_pairs[color_table_index][i] = distinct_values[i];
+                    bytestream2_put_byte(pb, distinct_values[i]);
+                }
+
+                color_pair_index++;
+                if (color_pair_index == COLORS_PER_TABLE)
+                    color_pair_index = 0;
+            }
+
+            for (int i = 0; i < blocks; i++) {
+                uint8_t value = s->color_pairs[color_table_index][1];
+                uint16_t flags = 0;
+                int shift = 15;
+
+                for (int y = 0; y < 4; y++) {
+                    for (int x = 0; x < 4; x++) {
+                        flags |= (value == pixel_ptr[x + y * stride]) << shift;
+                        shift--;
+                    }
+                }
+
+                bytestream2_put_be16(pb, flags);
+
+                ADVANCE_BLOCK(pixel_ptr, row_ptr, 1)
+            }
+            break;
+        case 3:
+        case 4:
+            cache_index = -1;
+            for (int i = 0; i < COLORS_PER_TABLE; i++) {
+                if (CACHE_QUAD(0) &&
+                    CACHE_QUAD(1) &&
+                    CACHE_QUAD(2) &&
+                    CACHE_QUAD(3)) {
+                    cache_index = i;
+                    break;
+                }
+            }
+
+            if (cache_index >= 0) {
+                bytestream2_put_byte(pb, 0xB0 | (blocks - 1));
+                bytestream2_put_byte(pb, cache_index);
+                color_table_index = cache_index;
+            } else {
+                bytestream2_put_byte(pb, 0xA0 | (blocks - 1));
+
+                color_table_index = color_quad_index;
+                for (int i = 0; i < CQUAD; i++) {
+                    s->color_quads[color_table_index][i] = distinct_values[i];
+                    bytestream2_put_byte(pb, distinct_values[i]);
+                }
+
+                color_quad_index++;
+                if (color_quad_index == COLORS_PER_TABLE)
+                    color_quad_index = 0;
+            }
+
+            for (int i = 0; i < blocks; i++) {
+                uint32_t flags = 0;
+                uint8_t quad[4];
+                int shift = 30;
+
+                for (int k = 0; k < 4; k++)
+                    quad[k] = s->color_quads[color_table_index][k];
+
+                for (int y = 0; y < 4; y++) {
+                    for (int x = 0; x < 4; x++) {
+                        int pixel = pixel_ptr[x + y * stride];
+                        uint32_t idx = 0;
+
+                        for (int w = 0; w < CQUAD; w++) {
+                            if (quad[w] == pixel) {
+                                idx = w;
+                                break;
+                            }
+                        }
+
+                        flags |= idx << shift;
+                        shift -= 2;
+                    }
+                }
+
+                bytestream2_put_be32(pb, flags);
+
+                ADVANCE_BLOCK(pixel_ptr, row_ptr, 1)
+            }
+            break;
+        case 5:
+        case 6:
+        case 7:
+        case 8:
+            cache_index = -1;
+            for (int i = 0; i < COLORS_PER_TABLE; i++) {
+                if (CACHE_OCTET(0) &&
+                    CACHE_OCTET(1) &&
+                    CACHE_OCTET(2) &&
+                    CACHE_OCTET(3) &&
+                    CACHE_OCTET(4) &&
+                    CACHE_OCTET(5) &&
+                    CACHE_OCTET(6) &&
+                    CACHE_OCTET(7)) {
+                    cache_index = i;
+                    break;
+                }
+            }
+
+            if (cache_index >= 0) {
+                bytestream2_put_byte(pb, 0xD0 | (blocks - 1));
+                bytestream2_put_byte(pb, cache_index);
+                color_table_index = cache_index;
+            } else {
+                bytestream2_put_byte(pb, 0xC0 | (blocks - 1));
+
+                color_table_index = color_octet_index;
+                for (int i = 0; i < COCTET; i++) {
+                    s->color_octets[color_table_index][i] = distinct_values[i];
+                    bytestream2_put_byte(pb, distinct_values[i]);
+                }
+
+                color_octet_index++;
+                if (color_octet_index == COLORS_PER_TABLE)
+                    color_octet_index = 0;
+            }
+
+            for (int i = 0; i < blocks; i++) {
+                uint64_t flags = 0;
+                uint8_t octet[8];
+                int shift = 45;
+
+                for (int k = 0; k < 8; k++)
+                    octet[k] = s->color_octets[color_table_index][k];
+
+                for (int y = 0; y < 4; y++) {
+                    for (int x = 0; x < 4; x++) {
+                        int pixel = pixel_ptr[x + y * stride];
+                        uint64_t idx = 0;
+
+                        for (int w = 0; w < COCTET; w++) {
+                            if (octet[w] == pixel) {
+                                idx = w;
+                                break;
+                            }
+                        }
+
+                        flags |= idx << shift;
+                        shift -= 3;
+                    }
+                }
+
+                bytestream2_put_be16(pb, ((flags >> 32) & 0xFFF0) | ((flags >> 8) & 0xF));
+                bytestream2_put_be16(pb, ((flags >> 20) & 0xFFF0) | ((flags >> 4) & 0xF));
+                bytestream2_put_be16(pb, ((flags >>  8) & 0xFFF0) | ((flags >> 0) & 0xF));
+
+                ADVANCE_BLOCK(pixel_ptr, row_ptr, 1)
+            }
+            break;
+        default:
+            bytestream2_put_byte(pb, 0xE0 | (blocks - 1));
+            for (int i = 0; i < blocks; i++) {
+                for (int y = 0; y < 4; y++) {
+                    for (int x = 0; x < 4; x++)
+                        bytestream2_put_byte(pb, pixel_ptr[x + y * stride]);
+                }
+
+                ADVANCE_BLOCK(pixel_ptr, row_ptr, 1)
+            }
+            break;
+        case 17:
+            bytestream2_put_byte(pb, 0x20 | (blocks - 1));
+            ADVANCE_BLOCK(pixel_ptr, row_ptr, blocks)
+            break;
+        case 18:
+            bytestream2_put_byte(pb, 0x30);
+            bytestream2_put_byte(pb, blocks - 1);
+            ADVANCE_BLOCK(pixel_ptr, row_ptr, blocks)
+            break;
+        case 19:
+            bytestream2_put_byte(pb, 0x00 | (blocks - 1));
+            ADVANCE_BLOCK(pixel_ptr, row_ptr, blocks)
+            break;
+        case 20:
+            bytestream2_put_byte(pb, 0x10);
+            bytestream2_put_byte(pb, blocks - 1);
+            ADVANCE_BLOCK(pixel_ptr, row_ptr, blocks)
+            break;
+        }
+
+        block_counter += blocks;
+    }
+}
+
+static int smc_encode_init(AVCodecContext *avctx)
+{
+    SMCContext *s = avctx->priv_data;
+
+    avctx->bits_per_coded_sample = 8;
+
+    s->prev_frame = av_frame_alloc();
+    if (!s->prev_frame)
+        return AVERROR(ENOMEM);
+
+    return 0;
+}
+
+static int smc_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
+                                const AVFrame *frame, int *got_packet)
+{
+    SMCContext *s = avctx->priv_data;
+    const AVFrame *pict = frame;
+    uint8_t *pal;
+    int ret;
+
+    ret = ff_alloc_packet(avctx, pkt, 8LL * avctx->height * avctx->width);
+    if (ret < 0)
+        return ret;
+
+    if (avctx->gop_size == 0 || !s->prev_frame->data[0] ||
+        (avctx->frame_number % avctx->gop_size) == 0) {
+        s->key_frame = 1;
+    } else {
+        s->key_frame = 0;
+    }
+
+    bytestream2_init_writer(&s->pb, pkt->data, pkt->size);
+
+    bytestream2_put_be32(&s->pb, 0x00);
+
+    pal = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE, AVPALETTE_SIZE);
+    if (!pal)
+        return AVERROR(ENOMEM);
+    memcpy(pal, frame->data[1], AVPALETTE_SIZE);
+
+    smc_encode_stream(s, pict);
+
+    av_shrink_packet(pkt, bytestream2_tell_p(&s->pb));
+
+    pkt->data[0] = 0x0;
+
+    // write chunk length
+    AV_WB24(pkt->data + 1, pkt->size);
+
+    av_frame_unref(s->prev_frame);
+    ret = av_frame_ref(s->prev_frame, frame);
+    if (ret < 0) {
+        av_log(avctx, AV_LOG_ERROR, "cannot add reference\n");
+        return ret;
+    }
+
+    if (s->key_frame)
+        pkt->flags |= AV_PKT_FLAG_KEY;
+
+    *got_packet = 1;
+
+    return 0;
+}
+
+static int smc_encode_end(AVCodecContext *avctx)
+{
+    SMCContext *s = (SMCContext *)avctx->priv_data;
+
+    av_frame_free(&s->prev_frame);
+
+    return 0;
+}
+
+const AVCodec ff_smc_encoder = {
+    .name           = "smc",
+    .long_name      = NULL_IF_CONFIG_SMALL("QuickTime Graphics (SMC)"),
+    .type           = AVMEDIA_TYPE_VIDEO,
+    .id             = AV_CODEC_ID_SMC,
+    .priv_data_size = sizeof(SMCContext),
+    .init           = smc_encode_init,
+    .encode2        = smc_encode_frame,
+    .close          = smc_encode_end,
+    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
+    .pix_fmts       = (const enum AVPixelFormat[]) { AV_PIX_FMT_PAL8,
+                                                     AV_PIX_FMT_NONE},
+};
diff --git a/libavcodec/version.h b/libavcodec/version.h
index c2482428ca..8cdbb4ecf3 100644
--- a/libavcodec/version.h
+++ b/libavcodec/version.h
@@ -28,8 +28,8 @@
 #include "libavutil/version.h"
 
 #define LIBAVCODEC_VERSION_MAJOR  59
-#define LIBAVCODEC_VERSION_MINOR   4
-#define LIBAVCODEC_VERSION_MICRO 101
+#define LIBAVCODEC_VERSION_MINOR   5
+#define LIBAVCODEC_VERSION_MICRO 100
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
                                                LIBAVCODEC_VERSION_MINOR, \