@@ -34,6 +34,7 @@ version <next>:

 - RTSP listen mode

 - TechSmith Screen Codec 2 decoder

 - AAC encoding via libfdk-aac

+- Microsoft Expression Encoder Screen decoder

 version 0.8:

@@ -541,6 +541,8 @@ following image formats are supported:

 @item lossless MJPEG         @tab  X  @tab  X

 @item Microsoft ATC Screen   @tab     @tab  X

     @tab Also known as Microsoft Screen 3.

+@item Microsoft Expression Encoder Screen  @tab     @tab  X

+    @tab Also known as Microsoft Titanium Screen 2.

 @item Microsoft RLE          @tab     @tab  X

 @item Microsoft Screen 1     @tab     @tab  X

     @tab Also known as Windows Media Video V7 Screen.

@@ -296,6 +296,7 @@ OBJS-$(CONFIG_MSA1_DECODER)            += mss3.o mss34dsp.o

 OBJS-$(CONFIG_MSS1_DECODER)            += mss1.o

 OBJS-$(CONFIG_MSVIDEO1_DECODER)        += msvideo1.o

 OBJS-$(CONFIG_MSZH_DECODER)            += lcldec.o

+OBJS-$(CONFIG_MTS2_DECODER)            += mss4.o mss34dsp.o

 OBJS-$(CONFIG_MXPEG_DECODER)           += mxpegdec.o mjpegdec.o mjpeg.o

 OBJS-$(CONFIG_NELLYMOSER_DECODER)      += nellymoserdec.o nellymoser.o

 OBJS-$(CONFIG_NELLYMOSER_ENCODER)      += nellymoserenc.o nellymoser.o \

@@ -160,6 +160,7 @@ void avcodec_register_all(void)

     REGISTER_DECODER (MSS1, mss1);

     REGISTER_DECODER (MSVIDEO1, msvideo1);

     REGISTER_DECODER (MSZH, mszh);

+    REGISTER_DECODER (MTS2, mts2);

     REGISTER_DECODER (MXPEG, mxpeg);

     REGISTER_DECODER (NUV, nuv);

     REGISTER_ENCDEC  (PAM, pam);

@@ -258,6 +258,7 @@ enum CodecID {

     CODEC_ID_MSS1,

     CODEC_ID_MSA1,

     CODEC_ID_TSCC2,

+    CODEC_ID_MTS2,

     /* various PCM "codecs" */

     CODEC_ID_FIRST_AUDIO = 0x10000,     ///< A dummy id pointing at the start of audio codecs

new file mode 100644

@@ -0,0 +1,682 @@

+/*

+ * Microsoft Screen 4 (aka Microsoft Expression Encoder Screen) decoder

+ * Copyright (c) 2012 Konstantin Shishkov

+ *

+ * This file is part of Libav.

+ *

+ * Libav 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.

+ *

+ * Libav 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 Libav; if not, write to the Free Software

+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

+ */

+

+/**

+ * @file

+ * Microsoft Screen 4 (aka Microsoft Titanium Screen 2,

+ * aka Microsoft Expression Encoder Screen) decoder

+ */

+

+#include "avcodec.h"

+#include "bytestream.h"

+#include "dsputil.h"

+#include "get_bits.h"

+#include "mss34dsp.h"

+#include "unary.h"

+

+#define HEADER_SIZE 8

+

+enum FrameType {

+    INTRA_FRAME = 0,

+    INTER_FRAME,

+    SKIP_FRAME

+};

+

+enum BlockType {

+    SKIP_BLOCK = 0,

+    DCT_BLOCK,

+    IMAGE_BLOCK,

+};

+

+enum CachePos {

+    LEFT = 0,

+    TOP_LEFT,

+    TOP,

+};

+

+static const uint8_t mss4_dc_vlc_lens[2][16] = {

+    { 0, 1, 5, 1, 1, 1, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0 },

+    { 0, 3, 1, 1, 1, 1, 1, 1, 1, 2, 0, 0, 0, 0, 0, 0 }

+};

+

+static const uint8_t mss4_ac_vlc_lens[2][16] = {

+    { 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 125 },

+    { 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 119 }

+};

+

+static const uint8_t mss4_ac_vlc_syms[2][162] = {

+  { 0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,

+    0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,

+    0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xA1, 0x08,

+    0x23, 0x42, 0xB1, 0xC1, 0x15, 0x52, 0xD1, 0xF0,

+    0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0A, 0x16,

+    0x17, 0x18, 0x19, 0x1A, 0x25, 0x26, 0x27, 0x28,

+    0x29, 0x2A, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,

+    0x3A, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,

+    0x4A, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,

+    0x5A, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,

+    0x6A, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,

+    0x7A, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,

+    0x8A, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,

+    0x99, 0x9A, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7,

+    0xA8, 0xA9, 0xAA, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6,

+    0xB7, 0xB8, 0xB9, 0xBA, 0xC2, 0xC3, 0xC4, 0xC5,

+    0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xD2, 0xD3, 0xD4,

+    0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xE1, 0xE2,

+    0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA,

+    0xF1, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8,

+    0xF9, 0xFA  },

+  { 0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,

+    0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,

+    0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,

+    0xA1, 0xB1, 0xC1, 0x09, 0x23, 0x33, 0x52, 0xF0,

+    0x15, 0x62, 0x72, 0xD1, 0x0A, 0x16, 0x24, 0x34,

+    0xE1, 0x25, 0xF1, 0x17, 0x18, 0x19, 0x1A, 0x26,

+    0x27, 0x28, 0x29, 0x2A, 0x35, 0x36, 0x37, 0x38,

+    0x39, 0x3A, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,

+    0x49, 0x4A, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,

+    0x59, 0x5A, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,

+    0x69, 0x6A, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,

+    0x79, 0x7A, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,

+    0x88, 0x89, 0x8A, 0x92, 0x93, 0x94, 0x95, 0x96,

+    0x97, 0x98, 0x99, 0x9A, 0xA2, 0xA3, 0xA4, 0xA5,

+    0xA6, 0xA7, 0xA8, 0xA9, 0xAA, 0xB2, 0xB3, 0xB4,

+    0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xC2, 0xC3,

+    0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xD2,

+    0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA,

+    0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9,

+    0xEA, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8,

+    0xF9, 0xFA  }

+};

+

+static const uint8_t vec_len_syms[2][4] = {

+    { 4, 2, 3, 1 },

+    { 4, 1, 2, 3 }

+};

+

+static const uint8_t mss4_vec_entry_vlc_lens[2][16] = {

+    { 0, 2, 2, 3, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },

+    { 0, 1, 5, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }

+};

+

+static const uint8_t mss4_vec_entry_vlc_syms[2][9] = {

+    { 0, 7, 6, 5, 8, 4, 3, 1, 2 },

+    { 0, 2, 3, 4, 5, 6, 7, 1, 8 }

+};

+

+#define MAX_ENTRIES  162

+

+typedef struct MSS4Context {

+    AVFrame    pic;

+    DSPContext dsp;

+

+    VLC        dc_vlc[2], ac_vlc[2];

+    VLC        vec_entry_vlc[2];

+    int        block[64];

+    uint8_t    imgbuf[3][16 * 16];

+

+    int        quality;

+    uint16_t   quant_mat[2][64];

+

+    int        *prev_dc[3];

+    int        dc_stride[3];

+    int        dc_cache[4][4];

+

+    int        prev_vec[3][4];

+} MSS4Context;

+

+static av_cold int mss4_init_vlc(VLC *vlc, const uint8_t *lens,

+                                 const uint8_t *syms, int num_syms)

+{

+    uint8_t  bits[MAX_ENTRIES];

+    uint16_t codes[MAX_ENTRIES];

+    int i, j;

+    int prefix = 0, max_bits = 0, idx = 0;

+

+    for (i = 0; i < 16; i++) {

+        for (j = 0; j < lens[i]; j++) {

+            bits[idx]  = i + 1;

+            codes[idx] = prefix++;

+            max_bits   = i + 1;

+            idx++;

+        }

+        prefix <<= 1;

+    }

+

+    return ff_init_vlc_sparse(vlc, FFMIN(max_bits, 9), num_syms, bits, 1, 1,

+                              codes, 2, 2, syms, 1, 1, 0);

+}

+

+static av_cold int mss4_init_vlcs(MSS4Context *ctx)

+{

+    int ret, i;

+

+    for (i = 0; i < 2; i++) {

+        ret = mss4_init_vlc(&ctx->dc_vlc[i], mss4_dc_vlc_lens[i], NULL, 12);

+        if (ret)

+            return ret;

+        ret = mss4_init_vlc(&ctx->ac_vlc[i], mss4_ac_vlc_lens[i],

+                            mss4_ac_vlc_syms[i], 162);

+        if (ret)

+            return ret;

+        ret = mss4_init_vlc(&ctx->vec_entry_vlc[i], mss4_vec_entry_vlc_lens[i],

+                            mss4_vec_entry_vlc_syms[i], 9);

+        if (ret)

+            return ret;

+    }

+    return 0;

+}

+

+static av_cold void mss4_free_vlcs(MSS4Context *ctx)

+{

+    int i;

+

+    for (i = 0; i < 2; i++) {

+        ff_free_vlc(&ctx->dc_vlc[i]);

+        ff_free_vlc(&ctx->ac_vlc[i]);

+        ff_free_vlc(&ctx->vec_entry_vlc[i]);

+    }

+}

+

+/* This function returns values in the range

+ * (-range + 1; -range/2] U [range/2; range - 1)

+ * i.e.

+ * nbits = 0 -> 0

+ * nbits = 1 -> -1, 1

+ * nbits = 2 -> -3, -2, 2, 3

+ */

+static av_always_inline int get_coeff_bits(GetBitContext *gb, int nbits)

+{

+    int val;

+

+    if (!nbits)

+        return 0;

+

+    val = get_bits(gb, nbits);

+    if (val < (1 << (nbits - 1)))

+        val -= (1 << nbits) - 1;

+

+    return val;

+}

+

+static inline int get_coeff(GetBitContext *gb, VLC *vlc)

+{

+    int val = get_vlc2(gb, vlc->table, vlc->bits, 2);

+

+    return get_coeff_bits(gb, val);

+}

+

+static int mss4_decode_dct(GetBitContext *gb, VLC *dc_vlc, VLC *ac_vlc,

+                           int *block, int *dc_cache,

+                           int bx, int by, uint16_t *quant_mat)

+{

+    int skip, val, pos = 1, zz_pos, dc;

+

+    memset(block, 0, sizeof(*block) * 64);

+

+    dc = get_coeff(gb, dc_vlc);

+    // DC prediction is the same as in MSS3

+    if (by) {

+        if (bx) {

+            int l, tl, t;

+

+            l  = dc_cache[LEFT];

+            tl = dc_cache[TOP_LEFT];

+            t  = dc_cache[TOP];

+

+            if (FFABS(t - tl) <= FFABS(l - tl))

+                dc += l;

+            else

+                dc += t;

+        } else {

+            dc += dc_cache[TOP];

+        }

+    } else if (bx) {

+        dc += dc_cache[LEFT];

+    }

+    dc_cache[LEFT] = dc;

+    block[0]       = dc * quant_mat[0];

+

+    while (pos < 64) {

+        val = get_vlc2(gb, ac_vlc->table, 9, 2);

+        if (!val)

+            return 0;

+        if (val == -1)

+            return -1;

+        if (val == 0xF0) {

+            pos += 16;

+            continue;

+        }

+        skip = val >> 4;

+        val  = get_coeff_bits(gb, val & 0xF);

+        pos += skip;

+        if (pos >= 64)

+            return -1;

+

+        zz_pos = ff_zigzag_direct[pos];

+        block[zz_pos] = val * quant_mat[zz_pos];

+        pos++;

+    }

+

+    return pos == 64 ? 0 : -1;

+}

+

+static int mss4_decode_dct_block(MSS4Context *c, GetBitContext *gb,

+                                 uint8_t *dst[3], int mb_x, int mb_y)

+{

+    int i, j, k, ret;

+    uint8_t *out = dst[0];

+

+    for (j = 0; j < 2; j++) {

+        for (i = 0; i < 2; i++) {

+            int xpos = mb_x * 2 + i;

+            c->dc_cache[j][TOP_LEFT] = c->dc_cache[j][TOP];

+            c->dc_cache[j][TOP]      = c->prev_dc[0][mb_x * 2 + i];

+            ret = mss4_decode_dct(gb, c->dc_vlc, c->ac_vlc, c->block,

+                                  c->dc_cache[j],

+                                  xpos, mb_y * 2 + j, c->quant_mat[0]);

+            if (ret)

+                return ret;

+            c->prev_dc[0][mb_x * 2 + i] = c->dc_cache[j][LEFT];

+

+            ff_mss34_dct_put(out + xpos * 8, c->pic.linesize[0],

+                             c->block);

+        }

+        out += 8 * c->pic.linesize[0];

+    }

+

+    for (i = 1; i < 3; i++) {

+        c->dc_cache[i + 1][TOP_LEFT] = c->dc_cache[i + 1][TOP];

+        c->dc_cache[i + 1][TOP]      = c->prev_dc[i][mb_x];

+        ret = mss4_decode_dct(gb, c->dc_vlc + 1, c->ac_vlc + 1,

+                              c->block, c->dc_cache[i + 1], mb_x, mb_y,

+                              c->quant_mat[1]);

+        if (ret)

+            return ret;

+        c->prev_dc[i][mb_x] = c->dc_cache[i + 1][LEFT];

+

+        ff_mss34_dct_put(c->imgbuf[i], 8, c->block);

+        out = dst[i] + mb_x * 16;

+        // Since the DCT block is coded as YUV420 and the whole frame as YUV444,

+        // we need to scale chroma.

+        for (j = 0; j < 16; j++) {

+            for (k = 0; k < 8; k++)

+                AV_WN16A(out + k * 2, c->imgbuf[i][k + (j & ~1) * 4] * 0x101);

+            out += c->pic.linesize[i];

+        }

+    }

+

+    return 0;

+}

+

+static void read_vec_pos(GetBitContext *gb, int *vec_pos, int *sel_flag,

+                         int *sel_len, int *prev)

+{

+    int i, y_flag = 0;

+

+    for (i = 2; i >= 0; i--) {

+        if (!sel_flag[i]) {

+            vec_pos[i] = 0;

+            continue;

+        }

+        if ((!i && !y_flag) || get_bits1(gb)) {

+            if (sel_len[i] > 0) {

+                int pval = prev[i];

+                vec_pos[i] = get_bits(gb, sel_len[i]);

+                if (vec_pos[i] >= pval)

+                    vec_pos[i]++;

+            } else {

+                vec_pos[i] = !prev[i];

+            }

+            y_flag = 1;

+        } else {

+            vec_pos[i] = prev[i];

+        }

+    }

+}

+

+static int get_value_cached(GetBitContext *gb, int vec_pos, uint8_t *vec,

+                            int vec_size, int component, int shift, int *prev)

+{

+    if (vec_pos < vec_size)

+        return vec[vec_pos];

+    if (!get_bits1(gb))

+        return prev[component];

+    prev[component] = get_bits(gb, 8 - shift) << shift;

+    return prev[component];

+}

+

+#define MKVAL(vals)  (vals[0] | (vals[1] << 3) | (vals[2] << 6))

+

+/* Image mode - the hardest to comprehend MSS4 coding mode.

+ *

+ * In this mode all three 16x16 blocks are coded together with a method

+ * remotely similar to the methods employed in MSS1-MSS3.

+ * The idea is that every component has a vector of 1-4 most common symbols

+ * and an escape mode for reading new value from the bitstream. Decoding

+ * consists of retrieving pixel values from the vector or reading new ones

+ * from the bitstream; depending on flags read from the bitstream, these vector

+ * positions can be updated or reused from the state of the previous line

+ * or previous pixel.

+ */

+static int mss4_decode_image_block(MSS4Context *ctx, GetBitContext *gb,

+                                   uint8_t *picdst[3], int mb_x, int mb_y)

+{

+    uint8_t vec[3][4];

+    int     vec_len[3];

+    int     sel_len[3], sel_flag[3];

+    int     i, j, k, mode, split;

+    int     prev_vec1 = 0, prev_split = 0;

+    int     vals[3] = { 0 };

+    int     prev_pix[3] = { 0 };

+    int     prev_mode[16] = { 0 };

+    uint8_t *dst[3];

+

+    const int val_shift = ctx->quality == 100 ? 0 : 2;

+

+    for (i = 0; i < 3; i++)

+        dst[i] = ctx->imgbuf[i];

+

+    for (i = 0; i < 3; i++) {

+        vec_len[i] = vec_len_syms[!!i][get_unary(gb, 0, 3)];

+        for (j = 0; j < vec_len[i]; j++) {

+            vec[i][j]  = get_coeff(gb, &ctx->vec_entry_vlc[!!i]);

+            vec[i][j] += ctx->prev_vec[i][j];

+            ctx->prev_vec[i][j] = vec[i][j];

+        }

+        sel_flag[i] = vec_len[i] > 1;

+        sel_len[i]  = vec_len[i] > 2 ? vec_len[i] - 2 : 0;

+    }

+

+    for (j = 0; j < 16; j++) {

+        if (get_bits1(gb)) {

+            split = 0;

+            if (get_bits1(gb)) {

+                prev_mode[0] = 0;

+                vals[0] = vals[1] = vals[2] = 0;

+                mode = 2;

+            } else {

+                mode = get_bits1(gb);

+                if (mode)

+                    split = get_bits(gb, 4);

+            }

+            for (i = 0; i < 16; i++) {

+                if (mode <= 1) {

+                    vals[0] =  prev_mode[i]       & 7;

+                    vals[1] = (prev_mode[i] >> 3) & 7;

+                    vals[2] =  prev_mode[i] >> 6;

+                    if (mode == 1 && i == split) {

+                        read_vec_pos(gb, vals, sel_flag, sel_len, vals);

+                    }

+                } else if (mode == 2) {

+                    if (get_bits1(gb))

+                        read_vec_pos(gb, vals, sel_flag, sel_len, vals);

+                }

+                for (k = 0; k < 3; k++)

+                    *dst[k]++ = get_value_cached(gb, vals[k], vec[k],

+                                                 vec_len[k], k,

+                                                 val_shift, prev_pix);

+                prev_mode[i] = MKVAL(vals);

+            }

+        } else {

+            if (get_bits1(gb)) {

+                split = get_bits(gb, 4);

+                if (split >= prev_split)

+                    split++;

+                prev_split = split;

+            } else {

+                split = prev_split;

+            }

+            if (split) {

+                vals[0] =  prev_mode[0]       & 7;

+                vals[1] = (prev_mode[0] >> 3) & 7;

+                vals[2] =  prev_mode[0] >> 6;

+                for (i = 0; i < 3; i++) {

+                    for (k = 0; k < split; k++) {

+                        *dst[i]++ = get_value_cached(gb, vals[i], vec[i],

+                                                     vec_len[i], i, val_shift,

+                                                     prev_pix);

+                        prev_mode[k] = MKVAL(vals);

+                    }

+                }

+            }

+

+            if (split != 16) {

+                vals[0] =  prev_vec1       & 7;

+                vals[1] = (prev_vec1 >> 3) & 7;

+                vals[2] =  prev_vec1 >> 6;

+                if (get_bits1(gb)) {

+                    read_vec_pos(gb, vals, sel_flag, sel_len, vals);

+                    prev_vec1 = MKVAL(vals);

+                }

+                for (i = 0; i < 3; i++) {

+                    for (k = 0; k < 16 - split; k++) {

+                        *dst[i]++ = get_value_cached(gb, vals[i], vec[i],

+                                                     vec_len[i], i, val_shift,

+                                                     prev_pix);

+                        prev_mode[split + k] = MKVAL(vals);

+                    }

+                }

+            }

+        }

+    }

+

+    for (i = 0; i < 3; i++)

+        for (j = 0; j < 16; j++)

+            memcpy(picdst[i] + mb_x * 16 + j * ctx->pic.linesize[i],

+                   ctx->imgbuf[i] + j * 16, 16);

+

+    return 0;

+}

+

+static inline void mss4_update_dc_cache(MSS4Context *c, int mb_x)

+{

+    int i;

+

+    c->dc_cache[0][TOP]  = c->prev_dc[0][mb_x * 2 + 1];

+    c->dc_cache[0][LEFT] = 0;

+    c->dc_cache[1][TOP]  = 0;

+    c->dc_cache[1][LEFT] = 0;

+

+    for (i = 0; i < 2; i++)

+        c->prev_dc[0][mb_x * 2 + i] = 0;

+

+    for (i = 1; i < 3; i++) {

+        c->dc_cache[i + 1][TOP]  = c->prev_dc[i][mb_x];

+        c->dc_cache[i + 1][LEFT] = 0;

+        c->prev_dc[i][mb_x]      = 0;

+    }

+}

+

+static int mss4_decode_frame(AVCodecContext *avctx, void *data, int *data_size,

+                             AVPacket *avpkt)

+{

+    const uint8_t *buf = avpkt->data;

+    int buf_size = avpkt->size;

+    MSS4Context *c = avctx->priv_data;

+    GetBitContext gb;

+    GetByteContext bc;

+    uint8_t *dst[3];

+    int width, height, quality, frame_type;

+    int x, y, i, mb_width, mb_height, blk_type;

+    int ret;

+

+    if (buf_size < HEADER_SIZE) {

+        av_log(avctx, AV_LOG_ERROR,

+               "Frame should have at least %d bytes, got %d instead\n",

+               HEADER_SIZE, buf_size);

+        return AVERROR_INVALIDDATA;

+    }

+

+    bytestream2_init(&bc, buf, buf_size);

+    width      = bytestream2_get_be16(&bc);

+    height     = bytestream2_get_be16(&bc);

+    bytestream2_skip(&bc, 2);

+    quality    = bytestream2_get_byte(&bc);

+    frame_type = bytestream2_get_byte(&bc);

+

+    if (width > avctx->width ||

+        height != avctx->height) {

+        av_log(avctx, AV_LOG_ERROR, "Invalid frame dimensions %dx%d\n",

+               width, height);

+        return AVERROR_INVALIDDATA;

+    }

+    if (quality < 1 || quality > 100) {

+        av_log(avctx, AV_LOG_ERROR, "Invalid quality setting %d\n", quality);

+        return AVERROR_INVALIDDATA;

+    }

+    if ((frame_type & ~3) || frame_type == 3) {

+        av_log(avctx, AV_LOG_ERROR, "Invalid frame type %d\n", frame_type);

+        return AVERROR_INVALIDDATA;

+    }

+

+    if (frame_type != SKIP_FRAME && !bytestream2_get_bytes_left(&bc)) {

+        av_log(avctx, AV_LOG_ERROR,

+               "Empty frame found but it is not a skip frame.\n");

+        return AVERROR_INVALIDDATA;

+    }

+

+    c->pic.reference    = 3;

+    c->pic.buffer_hints = FF_BUFFER_HINTS_VALID    |

+                          FF_BUFFER_HINTS_PRESERVE |

+                          FF_BUFFER_HINTS_REUSABLE;

+    if ((ret = avctx->reget_buffer(avctx, &c->pic)) < 0) {

+        av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");

+        return ret;

+    }

+    c->pic.key_frame = (frame_type == INTRA_FRAME);

+    c->pic.pict_type = (frame_type == INTRA_FRAME) ? AV_PICTURE_TYPE_I

+                                                   : AV_PICTURE_TYPE_P;

+    if (frame_type == SKIP_FRAME) {

+        *data_size = sizeof(AVFrame);

+        *(AVFrame*)data = c->pic;

+

+        return buf_size;

+    }

+

+    if (c->quality != quality) {

+        c->quality = quality;

+        for (i = 0; i < 2; i++)

+            ff_mss34_gen_quant_mat(c->quant_mat[i], quality, !i);

+    }

+

+    init_get_bits(&gb, buf + HEADER_SIZE, (buf_size - HEADER_SIZE) * 8);

+

+    mb_width  = FFALIGN(width,  16) >> 4;

+    mb_height = FFALIGN(height, 16) >> 4;

+    dst[0] = c->pic.data[0];

+    dst[1] = c->pic.data[1];

+    dst[2] = c->pic.data[2];

+

+    memset(c->prev_vec, 0, sizeof(c->prev_vec));

+    for (y = 0; y < mb_height; y++) {

+        memset(c->dc_cache, 0, sizeof(c->dc_cache));

+        for (x = 0; x < mb_width; x++) {

+            blk_type = decode012(&gb);

+            switch (blk_type) {

+            case DCT_BLOCK:

+                if (mss4_decode_dct_block(c, &gb, dst, x, y) < 0) {

+                    av_log(avctx, AV_LOG_ERROR,

+                           "Error decoding DCT block %d,%d\n",

+                           x, y);

+                    return AVERROR_INVALIDDATA;

+                }

+                break;

+            case IMAGE_BLOCK:

+                if (mss4_decode_image_block(c, &gb, dst, x, y) < 0) {

+                    av_log(avctx, AV_LOG_ERROR,

+                           "Error decoding VQ block %d,%d\n",

+                           x, y);

+                    return AVERROR_INVALIDDATA;

+                }

+                break;

+            case SKIP_BLOCK:

+                if (frame_type == INTRA_FRAME) {

+                    av_log(avctx, AV_LOG_ERROR, "Skip block in intra frame\n");

+                    return AVERROR_INVALIDDATA;

+                }

+                break;

+            }

+            if (blk_type != DCT_BLOCK)

+                mss4_update_dc_cache(c, x);

+        }

+        dst[0] += c->pic.linesize[0] * 16;

+        dst[1] += c->pic.linesize[1] * 16;

+        dst[2] += c->pic.linesize[2] * 16;

+    }

+

+    *data_size = sizeof(AVFrame);

+    *(AVFrame*)data = c->pic;

+

+    return buf_size;

+}

+

+static av_cold int mss4_decode_init(AVCodecContext *avctx)

+{

+    MSS4Context * const c = avctx->priv_data;

+    int i;

+

+    if (mss4_init_vlcs(c)) {

+        av_log(avctx, AV_LOG_ERROR, "Cannot initialise VLCs\n");

+        mss4_free_vlcs(c);

+        return AVERROR(ENOMEM);

+    }

+    for (i = 0; i < 3; i++) {

+        c->dc_stride[i] = FFALIGN(avctx->width, 16) >> (2 + !!i);

+        c->prev_dc[i]   = av_malloc(sizeof(**c->prev_dc) * c->dc_stride[i]);

+        if (!c->prev_dc[i]) {

+            av_log(avctx, AV_LOG_ERROR, "Cannot allocate buffer\n");

+            mss4_free_vlcs(c);

+            return AVERROR(ENOMEM);

+        }

+    }

+

+    avctx->pix_fmt     = PIX_FMT_YUV444P;

+    avctx->coded_frame = &c->pic;

+

+    return 0;

+}

+

+static av_cold int mss4_decode_end(AVCodecContext *avctx)

+{

+    MSS4Context * const c = avctx->priv_data;

+    int i;

+

+    if (c->pic.data[0])

+        avctx->release_buffer(avctx, &c->pic);

+    for (i = 0; i < 3; i++)

+        av_freep(&c->prev_dc[i]);

+    mss4_free_vlcs(c);

+

+    return 0;

+}

+

+AVCodec ff_mts2_decoder = {

+    .name           = "mts2",

+    .type           = AVMEDIA_TYPE_VIDEO,

+    .id             = CODEC_ID_MTS2,

+    .priv_data_size = sizeof(MSS4Context),

+    .init           = mss4_decode_init,

+    .close          = mss4_decode_end,

+    .decode         = mss4_decode_frame,

+    .capabilities   = CODEC_CAP_DR1,

+    .long_name      = NULL_IF_CONFIG_SMALL("MS Expression Encoder Screen"),

+};

@@ -27,7 +27,7 @@

  */

 #define LIBAVCODEC_VERSION_MAJOR 54

-#define LIBAVCODEC_VERSION_MINOR 19

+#define LIBAVCODEC_VERSION_MINOR 20

 #define LIBAVCODEC_VERSION_MICRO  0

 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \

@@ -287,6 +287,7 @@ const AVCodecTag ff_codec_bmp_tags[] = {

     { CODEC_ID_MSS1,         MKTAG('M', 'S', 'S', '1') },

     { CODEC_ID_MSA1,         MKTAG('M', 'S', 'A', '1') },

     { CODEC_ID_TSCC2,        MKTAG('T', 'S', 'C', '2') },

+    { CODEC_ID_MTS2,         MKTAG('M', 'T', 'S', '2') },

     { CODEC_ID_NONE,         0 }

 };