yading@10: /*
yading@10:  * Copyright (C) 2005  Ole André Vadla Ravnås <oleavr@gmail.com>
yading@10:  * Copyright (C) 2008  Ramiro Polla
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: #include <stdlib.h>
yading@10: #include <string.h>
yading@10: #include <stdint.h>
yading@10: 
yading@10: #include "avcodec.h"
yading@10: #include "internal.h"
yading@10: #include "get_bits.h"
yading@10: #include "bytestream.h"
yading@10: #include "dsputil.h"
yading@10: #include "hpeldsp.h"
yading@10: #include "thread.h"
yading@10: 
yading@10: #define MIMIC_HEADER_SIZE   20
yading@10: 
yading@10: typedef struct {
yading@10:     AVCodecContext *avctx;
yading@10: 
yading@10:     int             num_vblocks[3];
yading@10:     int             num_hblocks[3];
yading@10: 
yading@10:     void           *swap_buf;
yading@10:     int             swap_buf_size;
yading@10: 
yading@10:     int             cur_index;
yading@10:     int             prev_index;
yading@10: 
yading@10:     ThreadFrame     frames     [16];
yading@10:     AVPicture       flipped_ptrs[16];
yading@10: 
yading@10:     DECLARE_ALIGNED(16, int16_t, dct_block)[64];
yading@10: 
yading@10:     GetBitContext   gb;
yading@10:     ScanTable       scantable;
yading@10:     DSPContext      dsp;
yading@10:     HpelDSPContext  hdsp;
yading@10:     VLC             vlc;
yading@10: 
yading@10:     /* Kept in the context so multithreading can have a constant to read from */
yading@10:     int             next_cur_index;
yading@10:     int             next_prev_index;
yading@10: } MimicContext;
yading@10: 
yading@10: static const uint32_t huffcodes[] = {
yading@10:     0x0000000a, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
yading@10:     0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
yading@10:     0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x0000000b,
yading@10:     0x0000001b, 0x00000038, 0x00000078, 0x00000079, 0x0000007a, 0x000000f9,
yading@10:     0x000000fa, 0x000003fb, 0x000007f8, 0x000007f9, 0x000007fa, 0x000007fb,
yading@10:     0x00000ff8, 0x00000ff9, 0x00000001, 0x00000039, 0x0000007b, 0x000000fb,
yading@10:     0x000001f8, 0x000001f9, 0x00000ffa, 0x00000ffb, 0x00001ff8, 0x00001ff9,
yading@10:     0x00001ffa, 0x00001ffb, 0x00003ff8, 0x00003ff9, 0x00003ffa, 0x00000000,
yading@10:     0x00000004, 0x0000003a, 0x000001fa, 0x00003ffb, 0x00007ff8, 0x00007ff9,
yading@10:     0x00007ffa, 0x00007ffb, 0x0000fff8, 0x0000fff9, 0x0000fffa, 0x0000fffb,
yading@10:     0x0001fff8, 0x0001fff9, 0x0001fffa, 0x00000000, 0x0000000c, 0x000000f8,
yading@10:     0x000001fb, 0x0001fffb, 0x0003fff8, 0x0003fff9, 0x0003fffa, 0x0003fffb,
yading@10:     0x0007fff8, 0x0007fff9, 0x0007fffa, 0x0007fffb, 0x000ffff8, 0x000ffff9,
yading@10:     0x000ffffa, 0x00000000, 0x0000001a, 0x000003f8, 0x000ffffb, 0x001ffff8,
yading@10:     0x001ffff9, 0x001ffffa, 0x001ffffb, 0x003ffff8, 0x003ffff9, 0x003ffffa,
yading@10:     0x003ffffb, 0x007ffff8, 0x007ffff9, 0x007ffffa, 0x007ffffb, 0x00000000,
yading@10:     0x0000003b, 0x000003f9, 0x00fffff8, 0x00fffff9, 0x00fffffa, 0x00fffffb,
yading@10:     0x01fffff8, 0x01fffff9, 0x01fffffa, 0x01fffffb, 0x03fffff8, 0x03fffff9,
yading@10:     0x03fffffa, 0x03fffffb, 0x07fffff8, 0x00000000, 0x000003fa, 0x07fffff9,
yading@10:     0x07fffffa, 0x07fffffb, 0x0ffffff8, 0x0ffffff9, 0x0ffffffa, 0x0ffffffb,
yading@10:     0x1ffffff8, 0x1ffffff9, 0x1ffffffa, 0x1ffffffb, 0x3ffffff8, 0x3ffffff9,
yading@10:     0x3ffffffa,
yading@10: };
yading@10: 
yading@10: static const uint8_t huffbits[] = {
yading@10:      4,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
yading@10:      0,  0,  0,  0,  2,  4,  5,  6,  7,  7,  7,  8,
yading@10:      8, 10, 11, 11, 11, 11, 12, 12,  2,  6,  7,  8,
yading@10:      9,  9, 12, 12, 13, 13, 13, 13, 14, 14, 14,  0,
yading@10:      3,  6,  9, 14, 15, 15, 15, 15, 16, 16, 16, 16,
yading@10:     17, 17, 17,  0,  4,  8,  9, 17, 18, 18, 18, 18,
yading@10:     19, 19, 19, 19, 20, 20, 20,  0,  5, 10, 20, 21,
yading@10:     21, 21, 21, 22, 22, 22, 22, 23, 23, 23, 23,  0,
yading@10:      6, 10, 24, 24, 24, 24, 25, 25, 25, 25, 26, 26,
yading@10:     26, 26, 27,  0, 10, 27, 27, 27, 28, 28, 28, 28,
yading@10:     29, 29, 29, 29, 30, 30, 30,
yading@10: };
yading@10: 
yading@10: static const uint8_t col_zag[64] = {
yading@10:      0,  8,  1,  2,  9, 16, 24, 17,
yading@10:     10,  3,  4, 11, 18, 25, 32, 40,
yading@10:     33, 26, 19, 12,  5,  6, 13, 20,
yading@10:     27, 34, 41, 48, 56, 49, 42, 35,
yading@10:     28, 21, 14,  7, 15, 22, 29, 36,
yading@10:     43, 50, 57, 58, 51, 44, 37, 30,
yading@10:     23, 31, 38, 45, 52, 59, 39, 46,
yading@10:     53, 60, 61, 54, 47, 55, 62, 63,
yading@10: };
yading@10: 
yading@10: static av_cold int mimic_decode_end(AVCodecContext *avctx)
yading@10: {
yading@10:     MimicContext *ctx = avctx->priv_data;
yading@10:     int i;
yading@10: 
yading@10:     av_free(ctx->swap_buf);
yading@10: 
yading@10:     for (i = 0; i < FF_ARRAY_ELEMS(ctx->frames); i++) {
yading@10:         if (ctx->frames[i].f)
yading@10:             ff_thread_release_buffer(avctx, &ctx->frames[i]);
yading@10:         av_frame_free(&ctx->frames[i].f);
yading@10:     }
yading@10: 
yading@10:     if (!avctx->internal->is_copy)
yading@10:         ff_free_vlc(&ctx->vlc);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static av_cold int mimic_decode_init(AVCodecContext *avctx)
yading@10: {
yading@10:     MimicContext *ctx = avctx->priv_data;
yading@10:     int ret, i;
yading@10: 
yading@10:     avctx->internal->allocate_progress = 1;
yading@10: 
yading@10:     ctx->prev_index = 0;
yading@10:     ctx->cur_index  = 15;
yading@10: 
yading@10:     if ((ret = init_vlc(&ctx->vlc, 11, FF_ARRAY_ELEMS(huffbits),
yading@10:                         huffbits, 1, 1, huffcodes, 4, 4, 0)) < 0) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "error initializing vlc table\n");
yading@10:         return ret;
yading@10:     }
yading@10:     ff_dsputil_init(&ctx->dsp, avctx);
yading@10:     ff_hpeldsp_init(&ctx->hdsp, avctx->flags);
yading@10:     ff_init_scantable(ctx->dsp.idct_permutation, &ctx->scantable, col_zag);
yading@10: 
yading@10:     for (i = 0; i < FF_ARRAY_ELEMS(ctx->frames); i++) {
yading@10:         ctx->frames[i].f = av_frame_alloc();
yading@10:         if (!ctx->frames[i].f) {
yading@10:             mimic_decode_end(avctx);
yading@10:             return AVERROR(ENOMEM);
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int mimic_decode_update_thread_context(AVCodecContext *avctx, const AVCodecContext *avctx_from)
yading@10: {
yading@10:     MimicContext *dst = avctx->priv_data, *src = avctx_from->priv_data;
yading@10:     int i, ret;
yading@10: 
yading@10:     if (avctx == avctx_from)
yading@10:         return 0;
yading@10: 
yading@10:     dst->cur_index  = src->next_cur_index;
yading@10:     dst->prev_index = src->next_prev_index;
yading@10: 
yading@10:     memcpy(dst->flipped_ptrs, src->flipped_ptrs, sizeof(src->flipped_ptrs));
yading@10: 
yading@10:     for (i = 0; i < FF_ARRAY_ELEMS(dst->frames); i++) {
yading@10:         ff_thread_release_buffer(avctx, &dst->frames[i]);
yading@10:         if (src->frames[i].f->data[0]) {
yading@10:             ret = ff_thread_ref_frame(&dst->frames[i], &src->frames[i]);
yading@10:             if (ret < 0)
yading@10:                 return ret;
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static const int8_t vlcdec_lookup[9][64] = {
yading@10:     {    0, },
yading@10:     {   -1,   1, },
yading@10:     {   -3,   3,   -2,   2, },
yading@10:     {   -7,   7,   -6,   6,   -5,   5,   -4,   4, },
yading@10:     {  -15,  15,  -14,  14,  -13,  13,  -12,  12,
yading@10:        -11,  11,  -10,  10,   -9,   9,   -8,   8, },
yading@10:     {  -31,  31,  -30,  30,  -29,  29,  -28,  28,
yading@10:        -27,  27,  -26,  26,  -25,  25,  -24,  24,
yading@10:        -23,  23,  -22,  22,  -21,  21,  -20,  20,
yading@10:        -19,  19,  -18,  18,  -17,  17,  -16,  16, },
yading@10:     {  -63,  63,  -62,  62,  -61,  61,  -60,  60,
yading@10:        -59,  59,  -58,  58,  -57,  57,  -56,  56,
yading@10:        -55,  55,  -54,  54,  -53,  53,  -52,  52,
yading@10:        -51,  51,  -50,  50,  -49,  49,  -48,  48,
yading@10:        -47,  47,  -46,  46,  -45,  45,  -44,  44,
yading@10:        -43,  43,  -42,  42,  -41,  41,  -40,  40,
yading@10:        -39,  39,  -38,  38,  -37,  37,  -36,  36,
yading@10:        -35,  35,  -34,  34,  -33,  33,  -32,  32, },
yading@10:     { -127, 127, -126, 126, -125, 125, -124, 124,
yading@10:       -123, 123, -122, 122, -121, 121, -120, 120,
yading@10:       -119, 119, -118, 118, -117, 117, -116, 116,
yading@10:       -115, 115, -114, 114, -113, 113, -112, 112,
yading@10:       -111, 111, -110, 110, -109, 109, -108, 108,
yading@10:       -107, 107, -106, 106, -105, 105, -104, 104,
yading@10:       -103, 103, -102, 102, -101, 101, -100, 100,
yading@10:        -99,  99,  -98,  98,  -97,  97,  -96,  96, },
yading@10:     {  -95,  95,  -94,  94,  -93,  93,  -92,  92,
yading@10:        -91,  91,  -90,  90,  -89,  89,  -88,  88,
yading@10:        -87,  87,  -86,  86,  -85,  85,  -84,  84,
yading@10:        -83,  83,  -82,  82,  -81,  81,  -80,  80,
yading@10:        -79,  79,  -78,  78,  -77,  77,  -76,  76,
yading@10:        -75,  75,  -74,  74,  -73,  73,  -72,  72,
yading@10:        -71,  71,  -70,  70,  -69,  69,  -68,  68,
yading@10:        -67,  67,  -66,  66,  -65,  65,  -64,  64, },
yading@10: };
yading@10: 
yading@10: static int vlc_decode_block(MimicContext *ctx, int num_coeffs, int qscale)
yading@10: {
yading@10:     int16_t *block = ctx->dct_block;
yading@10:     unsigned int pos;
yading@10: 
yading@10:     ctx->dsp.clear_block(block);
yading@10: 
yading@10:     block[0] = get_bits(&ctx->gb, 8) << 3;
yading@10: 
yading@10:     for (pos = 1; pos < num_coeffs; pos++) {
yading@10:         uint32_t vlc, num_bits;
yading@10:         int value;
yading@10:         int coeff;
yading@10: 
yading@10:         vlc = get_vlc2(&ctx->gb, ctx->vlc.table, ctx->vlc.bits, 3);
yading@10:         if (!vlc) /* end-of-block code */
yading@10:             return 0;
yading@10:         if (vlc == -1)
yading@10:             return AVERROR_INVALIDDATA;
yading@10: 
yading@10:         /* pos_add and num_bits are coded in the vlc code */
yading@10:         pos     += vlc & 15; // pos_add
yading@10:         num_bits = vlc >> 4; // num_bits
yading@10: 
yading@10:         if (pos >= 64)
yading@10:             return AVERROR_INVALIDDATA;
yading@10: 
yading@10:         value = get_bits(&ctx->gb, num_bits);
yading@10: 
yading@10:         /* FFmpeg's IDCT behaves somewhat different from the original code, so
yading@10:          * a factor of 4 was added to the input */
yading@10: 
yading@10:         coeff = vlcdec_lookup[num_bits][value];
yading@10:         if (pos < 3)
yading@10:             coeff <<= 4;
yading@10:         else /* TODO Use >> 10 instead of / 1001 */
yading@10:             coeff = (coeff * qscale) / 1001;
yading@10: 
yading@10:         block[ctx->scantable.permutated[pos]] = coeff;
yading@10:     }
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int decode(MimicContext *ctx, int quality, int num_coeffs,
yading@10:                   int is_iframe)
yading@10: {
yading@10:     int ret, y, x, plane, cur_row = 0;
yading@10: 
yading@10:     for (plane = 0; plane < 3; plane++) {
yading@10:         const int is_chroma = !!plane;
yading@10:         const int qscale    = av_clip(10000 - quality, is_chroma ? 1000 : 2000,
yading@10:                                       10000) << 2;
yading@10:         const int stride    = ctx->flipped_ptrs[ctx->cur_index ].linesize[plane];
yading@10:         const uint8_t *src  = ctx->flipped_ptrs[ctx->prev_index].data[plane];
yading@10:         uint8_t       *dst  = ctx->flipped_ptrs[ctx->cur_index ].data[plane];
yading@10: 
yading@10:         for (y = 0; y < ctx->num_vblocks[plane]; y++) {
yading@10:             for (x = 0; x < ctx->num_hblocks[plane]; x++) {
yading@10:                 /* Check for a change condition in the current block.
yading@10:                  * - iframes always change.
yading@10:                  * - Luma plane changes on get_bits1 == 0
yading@10:                  * - Chroma planes change on get_bits1 == 1 */
yading@10:                 if (is_iframe || get_bits1(&ctx->gb) == is_chroma) {
yading@10:                     /* Luma planes may use a backreference from the 15 last
yading@10:                      * frames preceding the previous. (get_bits1 == 1)
yading@10:                      * Chroma planes don't use backreferences. */
yading@10:                     if (is_chroma || is_iframe || !get_bits1(&ctx->gb)) {
yading@10:                         if ((ret = vlc_decode_block(ctx, num_coeffs,
yading@10:                                                     qscale)) < 0) {
yading@10:                             av_log(ctx->avctx, AV_LOG_ERROR, "Error decoding "
yading@10:                                    "block.\n");
yading@10:                             return ret;
yading@10:                         }
yading@10:                         ctx->dsp.idct_put(dst, stride, ctx->dct_block);
yading@10:                     } else {
yading@10:                         unsigned int backref = get_bits(&ctx->gb, 4);
yading@10:                         int index            = (ctx->cur_index + backref) & 15;
yading@10:                         uint8_t *p           = ctx->flipped_ptrs[index].data[0];
yading@10: 
yading@10:                         if (index != ctx->cur_index && p) {
yading@10:                             ff_thread_await_progress(&ctx->frames[index],
yading@10:                                                      cur_row, 0);
yading@10:                             p += src -
yading@10:                                  ctx->flipped_ptrs[ctx->prev_index].data[plane];
yading@10:                             ctx->hdsp.put_pixels_tab[1][0](dst, p, stride, 8);
yading@10:                         } else {
yading@10:                             av_log(ctx->avctx, AV_LOG_ERROR,
yading@10:                                      "No such backreference! Buggy sample.\n");
yading@10:                         }
yading@10:                     }
yading@10:                 } else {
yading@10:                     ff_thread_await_progress(&ctx->frames[ctx->prev_index],
yading@10:                                              cur_row, 0);
yading@10:                     ctx->hdsp.put_pixels_tab[1][0](dst, src, stride, 8);
yading@10:                 }
yading@10:                 src += 8;
yading@10:                 dst += 8;
yading@10:             }
yading@10:             src += (stride - ctx->num_hblocks[plane]) << 3;
yading@10:             dst += (stride - ctx->num_hblocks[plane]) << 3;
yading@10: 
yading@10:             ff_thread_report_progress(&ctx->frames[ctx->cur_index],
yading@10:                                       cur_row++, 0);
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * Flip the buffer upside-down and put it in the YVU order to match the
yading@10:  * way Mimic encodes frames.
yading@10:  */
yading@10: static void prepare_avpic(MimicContext *ctx, AVPicture *dst, AVFrame *src)
yading@10: {
yading@10:     int i;
yading@10:     dst->data[0] = src->data[0] + ( ctx->avctx->height       - 1) * src->linesize[0];
yading@10:     dst->data[1] = src->data[2] + ((ctx->avctx->height >> 1) - 1) * src->linesize[2];
yading@10:     dst->data[2] = src->data[1] + ((ctx->avctx->height >> 1) - 1) * src->linesize[1];
yading@10:     for (i = 0; i < 3; i++)
yading@10:         dst->linesize[i] = -src->linesize[i];
yading@10: }
yading@10: 
yading@10: static int mimic_decode_frame(AVCodecContext *avctx, void *data,
yading@10:                               int *got_frame, AVPacket *avpkt)
yading@10: {
yading@10:     const uint8_t *buf = avpkt->data;
yading@10:     int buf_size       = avpkt->size;
yading@10:     int swap_buf_size  = buf_size - MIMIC_HEADER_SIZE;
yading@10:     MimicContext *ctx  = avctx->priv_data;
yading@10:     GetByteContext gb;
yading@10:     int is_pframe;
yading@10:     int width, height;
yading@10:     int quality, num_coeffs;
yading@10:     int res;
yading@10: 
yading@10:     if (buf_size <= MIMIC_HEADER_SIZE) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "insufficient data\n");
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     bytestream2_init(&gb, buf, MIMIC_HEADER_SIZE);
yading@10:     bytestream2_skip(&gb, 2); /* some constant (always 256) */
yading@10:     quality    = bytestream2_get_le16u(&gb);
yading@10:     width      = bytestream2_get_le16u(&gb);
yading@10:     height     = bytestream2_get_le16u(&gb);
yading@10:     bytestream2_skip(&gb, 4); /* some constant */
yading@10:     is_pframe  = bytestream2_get_le32u(&gb);
yading@10:     num_coeffs = bytestream2_get_byteu(&gb);
yading@10:     bytestream2_skip(&gb, 3); /* some constant */
yading@10: 
yading@10:     if (!ctx->avctx) {
yading@10:         int i;
yading@10: 
yading@10:         if (!(width == 160 && height == 120) &&
yading@10:             !(width == 320 && height == 240)) {
yading@10:             av_log(avctx, AV_LOG_ERROR, "invalid width/height!\n");
yading@10:             return AVERROR_INVALIDDATA;
yading@10:         }
yading@10: 
yading@10:         ctx->avctx     = avctx;
yading@10:         avctx->width   = width;
yading@10:         avctx->height  = height;
yading@10:         avctx->pix_fmt = AV_PIX_FMT_YUV420P;
yading@10:         for (i = 0; i < 3; i++) {
yading@10:             ctx->num_vblocks[i] = -((-height) >> (3 + !!i));
yading@10:             ctx->num_hblocks[i] =     width   >> (3 + !!i);
yading@10:         }
yading@10:     } else if (width != ctx->avctx->width || height != ctx->avctx->height) {
yading@10:         avpriv_request_sample(avctx, "Resolution changing");
yading@10:         return AVERROR_PATCHWELCOME;
yading@10:     }
yading@10: 
yading@10:     if (is_pframe && !ctx->frames[ctx->prev_index].f->data[0]) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "decoding must start with keyframe\n");
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     ff_thread_release_buffer(avctx, &ctx->frames[ctx->cur_index]);
yading@10:     ctx->frames[ctx->cur_index].f->pict_type = is_pframe ? AV_PICTURE_TYPE_P :
yading@10:                                                            AV_PICTURE_TYPE_I;
yading@10:     if ((res = ff_thread_get_buffer(avctx, &ctx->frames[ctx->cur_index],
yading@10:                                     AV_GET_BUFFER_FLAG_REF)) < 0)
yading@10:         return res;
yading@10: 
yading@10:     ctx->next_prev_index = ctx->cur_index;
yading@10:     ctx->next_cur_index  = (ctx->cur_index - 1) & 15;
yading@10: 
yading@10:     prepare_avpic(ctx, &ctx->flipped_ptrs[ctx->cur_index],
yading@10:                   ctx->frames[ctx->cur_index].f);
yading@10: 
yading@10:     ff_thread_finish_setup(avctx);
yading@10: 
yading@10:     av_fast_padded_malloc(&ctx->swap_buf, &ctx->swap_buf_size, swap_buf_size);
yading@10:     if (!ctx->swap_buf)
yading@10:         return AVERROR(ENOMEM);
yading@10: 
yading@10:     ctx->dsp.bswap_buf(ctx->swap_buf,
yading@10:                        (const uint32_t*) (buf + MIMIC_HEADER_SIZE),
yading@10:                        swap_buf_size >> 2);
yading@10:     init_get_bits(&ctx->gb, ctx->swap_buf, swap_buf_size << 3);
yading@10: 
yading@10:     res = decode(ctx, quality, num_coeffs, !is_pframe);
yading@10:     ff_thread_report_progress(&ctx->frames[ctx->cur_index], INT_MAX, 0);
yading@10:     if (res < 0) {
yading@10:         if (!(avctx->active_thread_type & FF_THREAD_FRAME)) {
yading@10:             ff_thread_release_buffer(avctx, &ctx->frames[ctx->cur_index]);
yading@10:             return res;
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     if ((res = av_frame_ref(data, ctx->frames[ctx->cur_index].f)) < 0)
yading@10:         return res;
yading@10:     *got_frame      = 1;
yading@10: 
yading@10:     ctx->prev_index = ctx->next_prev_index;
yading@10:     ctx->cur_index  = ctx->next_cur_index;
yading@10: 
yading@10:     /* Only release frames that aren't used for backreferences anymore */
yading@10:     ff_thread_release_buffer(avctx, &ctx->frames[ctx->cur_index]);
yading@10: 
yading@10:     return buf_size;
yading@10: }
yading@10: 
yading@10: static av_cold int mimic_init_thread_copy(AVCodecContext *avctx)
yading@10: {
yading@10:     MimicContext *ctx = avctx->priv_data;
yading@10:     int i;
yading@10: 
yading@10:     for (i = 0; i < FF_ARRAY_ELEMS(ctx->frames); i++) {
yading@10:         ctx->frames[i].f = av_frame_alloc();
yading@10:         if (!ctx->frames[i].f) {
yading@10:             mimic_decode_end(avctx);
yading@10:             return AVERROR(ENOMEM);
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: AVCodec ff_mimic_decoder = {
yading@10:     .name                  = "mimic",
yading@10:     .type                  = AVMEDIA_TYPE_VIDEO,
yading@10:     .id                    = AV_CODEC_ID_MIMIC,
yading@10:     .priv_data_size        = sizeof(MimicContext),
yading@10:     .init                  = mimic_decode_init,
yading@10:     .close                 = mimic_decode_end,
yading@10:     .decode                = mimic_decode_frame,
yading@10:     .capabilities          = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS,
yading@10:     .long_name             = NULL_IF_CONFIG_SMALL("Mimic"),
yading@10:     .update_thread_context = ONLY_IF_THREADS_ENABLED(mimic_decode_update_thread_context),
yading@10:     .init_thread_copy      = ONLY_IF_THREADS_ENABLED(mimic_init_thread_copy),
yading@10: };