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https://git.videolan.org/git/ffmpeg.git
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244 lines
6.8 KiB
C
244 lines
6.8 KiB
C
/*
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* American Laser Games MM Video Decoder
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* Copyright (c) 2006,2008 Peter Ross
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* American Laser Games MM Video Decoder
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* by Peter Ross (pross@xvid.org)
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*
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* The MM format was used by IBM-PC ports of ALG's "arcade shooter" games,
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* including Mad Dog McCree and Crime Patrol.
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*
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* Technical details here:
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* http://wiki.multimedia.cx/index.php?title=American_Laser_Games_MM
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*/
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#include "libavutil/intreadwrite.h"
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#include "avcodec.h"
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#include "bytestream.h"
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#include "internal.h"
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#define MM_PREAMBLE_SIZE 6
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#define MM_TYPE_INTER 0x5
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#define MM_TYPE_INTRA 0x8
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#define MM_TYPE_INTRA_HH 0xc
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#define MM_TYPE_INTER_HH 0xd
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#define MM_TYPE_INTRA_HHV 0xe
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#define MM_TYPE_INTER_HHV 0xf
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#define MM_TYPE_PALETTE 0x31
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typedef struct MmContext {
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AVCodecContext *avctx;
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AVFrame frame;
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int palette[AVPALETTE_COUNT];
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GetByteContext gb;
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} MmContext;
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static av_cold int mm_decode_init(AVCodecContext *avctx)
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{
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MmContext *s = avctx->priv_data;
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s->avctx = avctx;
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avctx->pix_fmt = AV_PIX_FMT_PAL8;
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avcodec_get_frame_defaults(&s->frame);
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return 0;
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}
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static int mm_decode_pal(MmContext *s)
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{
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int i;
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bytestream2_skip(&s->gb, 4);
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for (i = 0; i < 128; i++) {
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s->palette[i] = 0xFFU << 24 | bytestream2_get_be24(&s->gb);
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s->palette[i+128] = s->palette[i]<<2;
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}
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return 0;
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}
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/**
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* @param half_horiz Half horizontal resolution (0 or 1)
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* @param half_vert Half vertical resolution (0 or 1)
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*/
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static int mm_decode_intra(MmContext * s, int half_horiz, int half_vert)
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{
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int x = 0, y = 0;
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while (bytestream2_get_bytes_left(&s->gb) > 0) {
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int run_length, color;
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if (y >= s->avctx->height)
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return 0;
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color = bytestream2_get_byte(&s->gb);
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if (color & 0x80) {
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run_length = 1;
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}else{
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run_length = (color & 0x7f) + 2;
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color = bytestream2_get_byte(&s->gb);
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}
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if (half_horiz)
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run_length *=2;
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if (run_length > s->avctx->width - x)
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return AVERROR_INVALIDDATA;
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if (color) {
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memset(s->frame.data[0] + y*s->frame.linesize[0] + x, color, run_length);
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if (half_vert)
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memset(s->frame.data[0] + (y+1)*s->frame.linesize[0] + x, color, run_length);
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}
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x+= run_length;
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if (x >= s->avctx->width) {
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x=0;
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y += 1 + half_vert;
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}
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}
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return 0;
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}
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/**
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* @param half_horiz Half horizontal resolution (0 or 1)
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* @param half_vert Half vertical resolution (0 or 1)
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*/
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static int mm_decode_inter(MmContext * s, int half_horiz, int half_vert)
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{
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int data_off = bytestream2_get_le16(&s->gb), y = 0;
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GetByteContext data_ptr;
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if (bytestream2_get_bytes_left(&s->gb) < data_off)
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return AVERROR_INVALIDDATA;
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bytestream2_init(&data_ptr, s->gb.buffer + data_off, bytestream2_get_bytes_left(&s->gb) - data_off);
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while (s->gb.buffer < data_ptr.buffer_start) {
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int i, j;
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int length = bytestream2_get_byte(&s->gb);
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int x = bytestream2_get_byte(&s->gb) + ((length & 0x80) << 1);
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length &= 0x7F;
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if (length==0) {
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y += x;
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continue;
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}
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if (y + half_vert >= s->avctx->height)
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return 0;
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for(i=0; i<length; i++) {
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int replace_array = bytestream2_get_byte(&s->gb);
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for(j=0; j<8; j++) {
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int replace = (replace_array >> (7-j)) & 1;
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if (x + half_horiz >= s->avctx->width)
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return AVERROR_INVALIDDATA;
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if (replace) {
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int color = bytestream2_get_byte(&data_ptr);
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s->frame.data[0][y*s->frame.linesize[0] + x] = color;
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if (half_horiz)
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s->frame.data[0][y*s->frame.linesize[0] + x + 1] = color;
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if (half_vert) {
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s->frame.data[0][(y+1)*s->frame.linesize[0] + x] = color;
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if (half_horiz)
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s->frame.data[0][(y+1)*s->frame.linesize[0] + x + 1] = color;
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}
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}
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x += 1 + half_horiz;
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}
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}
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y += 1 + half_vert;
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}
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return 0;
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}
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static int mm_decode_frame(AVCodecContext *avctx,
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void *data, int *got_frame,
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AVPacket *avpkt)
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{
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const uint8_t *buf = avpkt->data;
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int buf_size = avpkt->size;
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MmContext *s = avctx->priv_data;
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int type, res;
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if (buf_size < MM_PREAMBLE_SIZE)
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return AVERROR_INVALIDDATA;
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type = AV_RL16(&buf[0]);
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buf += MM_PREAMBLE_SIZE;
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buf_size -= MM_PREAMBLE_SIZE;
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bytestream2_init(&s->gb, buf, buf_size);
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if ((res = ff_reget_buffer(avctx, &s->frame)) < 0)
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return res;
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switch(type) {
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case MM_TYPE_PALETTE : res = mm_decode_pal(s); return avpkt->size;
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case MM_TYPE_INTRA : res = mm_decode_intra(s, 0, 0); break;
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case MM_TYPE_INTRA_HH : res = mm_decode_intra(s, 1, 0); break;
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case MM_TYPE_INTRA_HHV : res = mm_decode_intra(s, 1, 1); break;
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case MM_TYPE_INTER : res = mm_decode_inter(s, 0, 0); break;
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case MM_TYPE_INTER_HH : res = mm_decode_inter(s, 1, 0); break;
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case MM_TYPE_INTER_HHV : res = mm_decode_inter(s, 1, 1); break;
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default:
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res = AVERROR_INVALIDDATA;
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break;
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}
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if (res < 0)
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return res;
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memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
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if ((res = av_frame_ref(data, &s->frame)) < 0)
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return res;
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*got_frame = 1;
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return avpkt->size;
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}
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static av_cold int mm_decode_end(AVCodecContext *avctx)
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{
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MmContext *s = avctx->priv_data;
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av_frame_unref(&s->frame);
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return 0;
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}
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AVCodec ff_mmvideo_decoder = {
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.name = "mmvideo",
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.type = AVMEDIA_TYPE_VIDEO,
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.id = AV_CODEC_ID_MMVIDEO,
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.priv_data_size = sizeof(MmContext),
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.init = mm_decode_init,
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.close = mm_decode_end,
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.decode = mm_decode_frame,
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.capabilities = CODEC_CAP_DR1,
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.long_name = NULL_IF_CONFIG_SMALL("American Laser Games MM Video"),
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};
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