LCOV - code coverage report
Current view: top level - libavcodec - mpegvideo_parser.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 116 133 87.2 %
Date: 2017-12-11 04:34:20 Functions: 3 4 75.0 %

          Line data    Source code
       1             : /*
       2             :  * MPEG-1 / MPEG-2 video parser
       3             :  * Copyright (c) 2000,2001 Fabrice Bellard
       4             :  * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
       5             :  *
       6             :  * This file is part of FFmpeg.
       7             :  *
       8             :  * FFmpeg is free software; you can redistribute it and/or
       9             :  * modify it under the terms of the GNU Lesser General Public
      10             :  * License as published by the Free Software Foundation; either
      11             :  * version 2.1 of the License, or (at your option) any later version.
      12             :  *
      13             :  * FFmpeg is distributed in the hope that it will be useful,
      14             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      15             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      16             :  * Lesser General Public License for more details.
      17             :  *
      18             :  * You should have received a copy of the GNU Lesser General Public
      19             :  * License along with FFmpeg; if not, write to the Free Software
      20             :  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
      21             :  */
      22             : 
      23             : #include "parser.h"
      24             : #include "mpeg12.h"
      25             : #include "internal.h"
      26             : 
      27             : struct MpvParseContext {
      28             :     ParseContext pc;
      29             :     AVRational frame_rate;
      30             :     int progressive_sequence;
      31             :     int width, height;
      32             : };
      33             : 
      34             : 
      35        8575 : static void mpegvideo_extract_headers(AVCodecParserContext *s,
      36             :                                       AVCodecContext *avctx,
      37             :                                       const uint8_t *buf, int buf_size)
      38             : {
      39        8575 :     struct MpvParseContext *pc = s->priv_data;
      40        8575 :     const uint8_t *buf_end = buf + buf_size;
      41             :     uint32_t start_code;
      42             :     int frame_rate_index, ext_type, bytes_left;
      43             :     int frame_rate_ext_n, frame_rate_ext_d;
      44             :     int top_field_first, repeat_first_field, progressive_frame;
      45             :     int horiz_size_ext, vert_size_ext, bit_rate_ext;
      46        8575 :     int did_set_size=0;
      47        8575 :     int set_dim_ret = 0;
      48        8575 :     int bit_rate = 0;
      49        8575 :     int vbv_delay = 0;
      50             :     int chroma_format;
      51        8575 :     enum AVPixelFormat pix_fmt = AV_PIX_FMT_NONE;
      52             : //FIXME replace the crap with get_bits()
      53        8575 :     s->repeat_pict = 0;
      54             : 
      55       40160 :     while (buf < buf_end) {
      56       31339 :         start_code= -1;
      57       31339 :         buf= avpriv_find_start_code(buf, buf_end, &start_code);
      58       31339 :         bytes_left = buf_end - buf;
      59       31339 :         switch(start_code) {
      60        8308 :         case PICTURE_START_CODE:
      61        8308 :             if (bytes_left >= 2) {
      62        8308 :                 s->pict_type = (buf[1] >> 3) & 7;
      63        8308 :                 if (bytes_left >= 4)
      64        8308 :                 vbv_delay = ((buf[1] & 0x07) << 13) | (buf[2] << 5) | (buf[3]  >> 3);
      65             :             }
      66        8308 :             break;
      67        1908 :         case SEQ_START_CODE:
      68        1908 :             if (bytes_left >= 7) {
      69        1908 :                 pc->width  = (buf[0] << 4) | (buf[1] >> 4);
      70        1908 :                 pc->height = ((buf[1] & 0x0f) << 8) | buf[2];
      71        1908 :                 if(!avctx->width || !avctx->height || !avctx->coded_width || !avctx->coded_height){
      72         165 :                     set_dim_ret = ff_set_dimensions(avctx, pc->width, pc->height);
      73         165 :                     did_set_size=1;
      74             :                 }
      75        1908 :                 pix_fmt = AV_PIX_FMT_YUV420P;
      76        1908 :                 frame_rate_index = buf[3] & 0xf;
      77        1908 :                 pc->frame_rate = avctx->framerate = ff_mpeg12_frame_rate_tab[frame_rate_index];
      78        1908 :                 bit_rate = (buf[4]<<10) | (buf[5]<<2) | (buf[6]>>6);
      79        1908 :                 avctx->codec_id = AV_CODEC_ID_MPEG1VIDEO;
      80        1908 :                 avctx->ticks_per_frame = 1;
      81             :             }
      82        1908 :             break;
      83        9983 :         case EXT_START_CODE:
      84        9983 :             if (bytes_left >= 1) {
      85        9983 :                 ext_type = (buf[0] >> 4);
      86        9983 :                 switch(ext_type) {
      87        1769 :                 case 0x1: /* sequence extension */
      88        1769 :                     if (bytes_left >= 6) {
      89        1769 :                         horiz_size_ext = ((buf[1] & 1) << 1) | (buf[2] >> 7);
      90        1769 :                         vert_size_ext = (buf[2] >> 5) & 3;
      91        1769 :                         bit_rate_ext = ((buf[2] & 0x1F)<<7) | (buf[3]>>1);
      92        1769 :                         frame_rate_ext_n = (buf[5] >> 5) & 3;
      93        1769 :                         frame_rate_ext_d = (buf[5] & 0x1f);
      94        1769 :                         pc->progressive_sequence = buf[1] & (1 << 3);
      95        1769 :                         avctx->has_b_frames= !(buf[5] >> 7);
      96             : 
      97        1769 :                         chroma_format = (buf[1] >> 1) & 3;
      98        1769 :                         switch (chroma_format) {
      99         740 :                         case 1: pix_fmt = AV_PIX_FMT_YUV420P; break;
     100        1029 :                         case 2: pix_fmt = AV_PIX_FMT_YUV422P; break;
     101           0 :                         case 3: pix_fmt = AV_PIX_FMT_YUV444P; break;
     102             :                         }
     103             : 
     104        1769 :                         pc->width  = (pc->width & 0xFFF) | (horiz_size_ext << 12);
     105        1769 :                         pc->height = (pc->height& 0xFFF) | ( vert_size_ext << 12);
     106        1769 :                         bit_rate = (bit_rate&0x3FFFF) | (bit_rate_ext << 18);
     107        1769 :                         if(did_set_size)
     108         151 :                             set_dim_ret = ff_set_dimensions(avctx, pc->width, pc->height);
     109        1769 :                         avctx->framerate.num = pc->frame_rate.num * (frame_rate_ext_n + 1);
     110        1769 :                         avctx->framerate.den = pc->frame_rate.den * (frame_rate_ext_d + 1);
     111        1769 :                         avctx->codec_id = AV_CODEC_ID_MPEG2VIDEO;
     112        1769 :                         avctx->ticks_per_frame = 2;
     113             :                     }
     114        1769 :                     break;
     115        7436 :                 case 0x8: /* picture coding extension */
     116        7436 :                     if (bytes_left >= 5) {
     117        7436 :                         top_field_first = buf[3] & (1 << 7);
     118        7436 :                         repeat_first_field = buf[3] & (1 << 1);
     119        7436 :                         progressive_frame = buf[4] & (1 << 7);
     120             : 
     121             :                         /* check if we must repeat the frame */
     122        7436 :                         s->repeat_pict = 1;
     123        7436 :                         if (repeat_first_field) {
     124           6 :                             if (pc->progressive_sequence) {
     125           0 :                                 if (top_field_first)
     126           0 :                                     s->repeat_pict = 5;
     127             :                                 else
     128           0 :                                     s->repeat_pict = 3;
     129           6 :                             } else if (progressive_frame) {
     130           6 :                                 s->repeat_pict = 2;
     131             :                             }
     132             :                         }
     133             : 
     134        7436 :                         if (!pc->progressive_sequence) {
     135        4329 :                             if (top_field_first)
     136        1578 :                                 s->field_order = AV_FIELD_TT;
     137             :                             else
     138        2751 :                                 s->field_order = AV_FIELD_BB;
     139             :                         } else
     140        3107 :                             s->field_order = AV_FIELD_PROGRESSIVE;
     141             :                     }
     142        7436 :                     break;
     143             :                 }
     144             :             }
     145        9983 :             break;
     146           0 :         case -1:
     147           0 :             goto the_end;
     148       11140 :         default:
     149             :             /* we stop parsing when we encounter a slice. It ensures
     150             :                that this function takes a negligible amount of time */
     151       22280 :             if (start_code >= SLICE_MIN_START_CODE &&
     152       11140 :                 start_code <= SLICE_MAX_START_CODE)
     153        8329 :                 goto the_end;
     154        2811 :             break;
     155             :         }
     156             :     }
     157         246 :  the_end: ;
     158        8575 :     if (set_dim_ret < 0)
     159           0 :         av_log(avctx, AV_LOG_ERROR, "Failed to set dimensions\n");
     160             : 
     161        8575 :     if (avctx->codec_id == AV_CODEC_ID_MPEG2VIDEO && bit_rate) {
     162        1769 :         avctx->rc_max_rate = 400LL*bit_rate;
     163             :     }
     164       10483 :     if (bit_rate &&
     165        2047 :         ((avctx->codec_id == AV_CODEC_ID_MPEG1VIDEO && bit_rate != 0x3FFFF) || vbv_delay != 0xFFFF)) {
     166        1019 :         avctx->bit_rate = 400LL*bit_rate;
     167             :     }
     168             : 
     169        8575 :     if (pix_fmt != AV_PIX_FMT_NONE) {
     170        1908 :         s->format = pix_fmt;
     171        1908 :         s->width  = pc->width;
     172        1908 :         s->height = pc->height;
     173        1908 :         s->coded_width  = FFALIGN(pc->width,  16);
     174        1908 :         s->coded_height = FFALIGN(pc->height, 16);
     175             :     }
     176             : 
     177             : #if FF_API_AVCTX_TIMEBASE
     178        8575 :     if (avctx->framerate.num)
     179        8290 :         avctx->time_base = av_inv_q(av_mul_q(avctx->framerate, (AVRational){avctx->ticks_per_frame, 1}));
     180             : #endif
     181        8575 : }
     182             : 
     183       47625 : static int mpegvideo_parse(AVCodecParserContext *s,
     184             :                            AVCodecContext *avctx,
     185             :                            const uint8_t **poutbuf, int *poutbuf_size,
     186             :                            const uint8_t *buf, int buf_size)
     187             : {
     188       47625 :     struct MpvParseContext *pc1 = s->priv_data;
     189       47625 :     ParseContext *pc= &pc1->pc;
     190             :     int next;
     191             : 
     192       47625 :     if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
     193        2713 :         next= buf_size;
     194             :     }else{
     195       44912 :         next= ff_mpeg1_find_frame_end(pc, buf, buf_size, s);
     196             : 
     197       44912 :         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
     198       39050 :             *poutbuf = NULL;
     199       39050 :             *poutbuf_size = 0;
     200       39050 :             return buf_size;
     201             :         }
     202             : 
     203             :     }
     204             :     /* we have a full frame : we just parse the first few MPEG headers
     205             :        to have the full timing information. The time take by this
     206             :        function should be negligible for uncorrupted streams */
     207        8575 :     mpegvideo_extract_headers(s, avctx, buf, buf_size);
     208             :     ff_dlog(NULL, "pict_type=%d frame_rate=%0.3f repeat_pict=%d\n",
     209             :             s->pict_type, av_q2d(avctx->framerate), s->repeat_pict);
     210             : 
     211        8575 :     *poutbuf = buf;
     212        8575 :     *poutbuf_size = buf_size;
     213        8575 :     return next;
     214             : }
     215             : 
     216           0 : static int mpegvideo_split(AVCodecContext *avctx,
     217             :                            const uint8_t *buf, int buf_size)
     218             : {
     219             :     int i;
     220           0 :     uint32_t state= -1;
     221           0 :     int found=0;
     222             : 
     223           0 :     for(i=0; i<buf_size; i++){
     224           0 :         state= (state<<8) | buf[i];
     225           0 :         if(state == 0x1B3){
     226           0 :             found=1;
     227           0 :         }else if(found && state != 0x1B5 && state < 0x200 && state >= 0x100)
     228           0 :             return i-3;
     229             :     }
     230           0 :     return 0;
     231             : }
     232             : 
     233         660 : static int mpegvideo_parse_init(AVCodecParserContext *s)
     234             : {
     235         660 :     s->pict_type = AV_PICTURE_TYPE_NONE; // first frame might be partial
     236         660 :     return 0;
     237             : }
     238             : 
     239             : AVCodecParser ff_mpegvideo_parser = {
     240             :     .codec_ids      = { AV_CODEC_ID_MPEG1VIDEO, AV_CODEC_ID_MPEG2VIDEO },
     241             :     .priv_data_size = sizeof(struct MpvParseContext),
     242             :     .parser_init    = mpegvideo_parse_init,
     243             :     .parser_parse   = mpegvideo_parse,
     244             :     .parser_close   = ff_parse_close,
     245             :     .split          = mpegvideo_split,
     246             : };

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