LCOV - code coverage report
Current view: top level - libavcodec - mjpegbdec.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 62 77 80.5 %
Date: 2017-12-12 03:56:30 Functions: 2 2 100.0 %

          Line data    Source code
       1             : /*
       2             :  * Apple MJPEG-B decoder
       3             :  * Copyright (c) 2002 Alex Beregszaszi
       4             :  *
       5             :  * This file is part of FFmpeg.
       6             :  *
       7             :  * FFmpeg is free software; you can redistribute it and/or
       8             :  * modify it under the terms of the GNU Lesser General Public
       9             :  * License as published by the Free Software Foundation; either
      10             :  * version 2.1 of the License, or (at your option) any later version.
      11             :  *
      12             :  * FFmpeg is distributed in the hope that it will be useful,
      13             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      14             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      15             :  * Lesser General Public License for more details.
      16             :  *
      17             :  * You should have received a copy of the GNU Lesser General Public
      18             :  * License along with FFmpeg; if not, write to the Free Software
      19             :  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
      20             :  */
      21             : 
      22             : /**
      23             :  * @file
      24             :  * Apple MJPEG-B decoder.
      25             :  */
      26             : 
      27             : #include <inttypes.h>
      28             : 
      29             : #include "avcodec.h"
      30             : #include "internal.h"
      31             : #include "mjpeg.h"
      32             : #include "mjpegdec.h"
      33             : 
      34         132 : static uint32_t read_offs(AVCodecContext *avctx, GetBitContext *gb, uint32_t size, const char *err_msg){
      35         132 :     uint32_t offs= get_bits_long(gb, 32);
      36         132 :     if(offs >= size){
      37           0 :         av_log(avctx, AV_LOG_WARNING, err_msg, offs, size);
      38           0 :         return 0;
      39             :     }
      40         132 :     return offs;
      41             : }
      42             : 
      43          11 : static int mjpegb_decode_frame(AVCodecContext *avctx,
      44             :                               void *data, int *got_frame,
      45             :                               AVPacket *avpkt)
      46             : {
      47          11 :     const uint8_t *buf = avpkt->data;
      48          11 :     int buf_size = avpkt->size;
      49          11 :     MJpegDecodeContext *s = avctx->priv_data;
      50             :     const uint8_t *buf_end, *buf_ptr;
      51             :     GetBitContext hgb; /* for the header */
      52             :     uint32_t dqt_offs, dht_offs, sof_offs, sos_offs, second_field_offs;
      53             :     uint32_t field_size, sod_offs;
      54             :     int ret;
      55             : 
      56          11 :     buf_ptr = buf;
      57          11 :     buf_end = buf + buf_size;
      58          11 :     s->got_picture = 0;
      59             : 
      60          22 : read_header:
      61             :     /* reset on every SOI */
      62          22 :     s->restart_interval = 0;
      63          22 :     s->restart_count = 0;
      64          22 :     s->mjpb_skiptosod = 0;
      65             : 
      66          22 :     if (buf_end - buf_ptr >= 1 << 28)
      67           0 :         return AVERROR_INVALIDDATA;
      68             : 
      69          22 :     init_get_bits(&hgb, buf_ptr, /*buf_size*/(buf_end - buf_ptr)*8);
      70             : 
      71          22 :     skip_bits(&hgb, 32); /* reserved zeros */
      72             : 
      73          22 :     if (get_bits_long(&hgb, 32) != MKBETAG('m','j','p','g'))
      74             :     {
      75           0 :         av_log(avctx, AV_LOG_WARNING, "not mjpeg-b (bad fourcc)\n");
      76           0 :         return AVERROR_INVALIDDATA;
      77             :     }
      78             : 
      79          22 :     field_size = get_bits_long(&hgb, 32); /* field size */
      80          22 :     av_log(avctx, AV_LOG_DEBUG, "field size: 0x%"PRIx32"\n", field_size);
      81          22 :     skip_bits(&hgb, 32); /* padded field size */
      82          22 :     second_field_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "second_field_offs is %d and size is %d\n");
      83          22 :     av_log(avctx, AV_LOG_DEBUG, "second field offs: 0x%"PRIx32"\n",
      84             :            second_field_offs);
      85             : 
      86          22 :     dqt_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "dqt is %d and size is %d\n");
      87          22 :     av_log(avctx, AV_LOG_DEBUG, "dqt offs: 0x%"PRIx32"\n", dqt_offs);
      88          22 :     if (dqt_offs)
      89             :     {
      90          22 :         init_get_bits(&s->gb, buf_ptr+dqt_offs, (buf_end - (buf_ptr+dqt_offs))*8);
      91          22 :         s->start_code = DQT;
      92          22 :         if (ff_mjpeg_decode_dqt(s) < 0 &&
      93           0 :             (avctx->err_recognition & AV_EF_EXPLODE))
      94           0 :           return AVERROR_INVALIDDATA;
      95             :     }
      96             : 
      97          22 :     dht_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "dht is %d and size is %d\n");
      98          22 :     av_log(avctx, AV_LOG_DEBUG, "dht offs: 0x%"PRIx32"\n", dht_offs);
      99          22 :     if (dht_offs)
     100             :     {
     101          22 :         init_get_bits(&s->gb, buf_ptr+dht_offs, (buf_end - (buf_ptr+dht_offs))*8);
     102          22 :         s->start_code = DHT;
     103          22 :         ff_mjpeg_decode_dht(s);
     104             :     }
     105             : 
     106          22 :     sof_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sof is %d and size is %d\n");
     107          22 :     av_log(avctx, AV_LOG_DEBUG, "sof offs: 0x%"PRIx32"\n", sof_offs);
     108          22 :     if (sof_offs)
     109             :     {
     110          22 :         init_get_bits(&s->gb, buf_ptr+sof_offs, (buf_end - (buf_ptr+sof_offs))*8);
     111          22 :         s->start_code = SOF0;
     112          22 :         if (ff_mjpeg_decode_sof(s) < 0)
     113           0 :             return -1;
     114             :     }
     115             : 
     116          22 :     sos_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sos is %d and size is %d\n");
     117          22 :     av_log(avctx, AV_LOG_DEBUG, "sos offs: 0x%"PRIx32"\n", sos_offs);
     118          22 :     sod_offs = read_offs(avctx, &hgb, buf_end - buf_ptr, "sof is %d and size is %d\n");
     119          22 :     av_log(avctx, AV_LOG_DEBUG, "sod offs: 0x%"PRIx32"\n", sod_offs);
     120          22 :     if (sos_offs)
     121             :     {
     122          22 :         init_get_bits(&s->gb, buf_ptr + sos_offs,
     123          22 :                       8 * FFMIN(field_size, buf_end - buf_ptr - sos_offs));
     124          22 :         s->mjpb_skiptosod = (sod_offs - sos_offs - show_bits(&s->gb, 16));
     125          22 :         s->start_code = SOS;
     126          22 :         if (ff_mjpeg_decode_sos(s, NULL, 0, NULL) < 0 &&
     127           0 :             (avctx->err_recognition & AV_EF_EXPLODE))
     128           0 :           return AVERROR_INVALIDDATA;
     129             :     }
     130             : 
     131          22 :     if (s->interlaced) {
     132          22 :         s->bottom_field ^= 1;
     133             :         /* if not bottom field, do not output image yet */
     134          22 :         if (s->bottom_field != s->interlace_polarity && second_field_offs)
     135             :         {
     136          11 :             buf_ptr = buf + second_field_offs;
     137          11 :             goto read_header;
     138             :             }
     139             :     }
     140             : 
     141             :     //XXX FIXME factorize, this looks very similar to the EOI code
     142             : 
     143          11 :     if(!s->got_picture) {
     144           0 :         av_log(avctx, AV_LOG_WARNING, "no picture\n");
     145           0 :         return buf_size;
     146             :     }
     147             : 
     148          11 :     if ((ret = av_frame_ref(data, s->picture_ptr)) < 0)
     149           0 :         return ret;
     150          11 :     *got_frame = 1;
     151             : 
     152          11 :     if (!s->lossless && avctx->debug & FF_DEBUG_QP) {
     153           0 :         av_log(avctx, AV_LOG_DEBUG, "QP: %d\n",
     154           0 :                FFMAX3(s->qscale[0], s->qscale[1], s->qscale[2]));
     155             :     }
     156             : 
     157          11 :     return buf_size;
     158             : }
     159             : 
     160             : AVCodec ff_mjpegb_decoder = {
     161             :     .name           = "mjpegb",
     162             :     .long_name      = NULL_IF_CONFIG_SMALL("Apple MJPEG-B"),
     163             :     .type           = AVMEDIA_TYPE_VIDEO,
     164             :     .id             = AV_CODEC_ID_MJPEGB,
     165             :     .priv_data_size = sizeof(MJpegDecodeContext),
     166             :     .init           = ff_mjpeg_decode_init,
     167             :     .close          = ff_mjpeg_decode_end,
     168             :     .decode         = mjpegb_decode_frame,
     169             :     .capabilities   = AV_CODEC_CAP_DR1,
     170             :     .max_lowres     = 3,
     171             :     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
     172             : };

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