LCOV - code coverage report
Current view: top level - libavcodec - cbs_mpeg2.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 124 147 84.4 %
Date: 2018-02-25 01:33:35 Functions: 9 9 100.0 %

          Line data    Source code
       1             : /*
       2             :  * This file is part of FFmpeg.
       3             :  *
       4             :  * FFmpeg is free software; you can redistribute it and/or
       5             :  * modify it under the terms of the GNU Lesser General Public
       6             :  * License as published by the Free Software Foundation; either
       7             :  * version 2.1 of the License, or (at your option) any later version.
       8             :  *
       9             :  * FFmpeg is distributed in the hope that it will be useful,
      10             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      11             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12             :  * Lesser General Public License for more details.
      13             :  *
      14             :  * You should have received a copy of the GNU Lesser General Public
      15             :  * License along with FFmpeg; if not, write to the Free Software
      16             :  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
      17             :  */
      18             : 
      19             : #include "libavutil/avassert.h"
      20             : 
      21             : #include "cbs.h"
      22             : #include "cbs_internal.h"
      23             : #include "cbs_mpeg2.h"
      24             : #include "internal.h"
      25             : 
      26             : 
      27             : #define HEADER(name) do { \
      28             :         ff_cbs_trace_header(ctx, name); \
      29             :     } while (0)
      30             : 
      31             : #define CHECK(call) do { \
      32             :         err = (call); \
      33             :         if (err < 0) \
      34             :             return err; \
      35             :     } while (0)
      36             : 
      37             : #define FUNC_NAME(rw, codec, name) cbs_ ## codec ## _ ## rw ## _ ## name
      38             : #define FUNC_MPEG2(rw, name) FUNC_NAME(rw, mpeg2, name)
      39             : #define FUNC(name) FUNC_MPEG2(READWRITE, name)
      40             : 
      41             : 
      42             : #define READ
      43             : #define READWRITE read
      44             : #define RWContext GetBitContext
      45             : 
      46             : #define xui(width, name, var) do { \
      47             :         uint32_t value = 0; \
      48             :         CHECK(ff_cbs_read_unsigned(ctx, rw, width, #name, \
      49             :                                    &value, 0, (1 << width) - 1)); \
      50             :         var = value; \
      51             :     } while (0)
      52             : 
      53             : #define ui(width, name) \
      54             :         xui(width, name, current->name)
      55             : 
      56             : #define marker_bit() do { \
      57             :         av_unused uint32_t one; \
      58             :         CHECK(ff_cbs_read_unsigned(ctx, rw, 1, "marker_bit", &one, 1, 1)); \
      59             :     } while (0)
      60             : 
      61             : #define nextbits(width, compare, var) \
      62             :     (get_bits_left(rw) >= width && \
      63             :      (var = show_bits(rw, width)) == (compare))
      64             : 
      65             : #include "cbs_mpeg2_syntax_template.c"
      66             : 
      67             : #undef READ
      68             : #undef READWRITE
      69             : #undef RWContext
      70             : #undef xui
      71             : #undef ui
      72             : #undef marker_bit
      73             : #undef nextbits
      74             : 
      75             : 
      76             : #define WRITE
      77             : #define READWRITE write
      78             : #define RWContext PutBitContext
      79             : 
      80             : #define xui(width, name, var) do { \
      81             :         CHECK(ff_cbs_write_unsigned(ctx, rw, width, #name, \
      82             :                                     var, 0, (1 << width) - 1)); \
      83             :     } while (0)
      84             : 
      85             : #define ui(width, name) \
      86             :         xui(width, name, current->name)
      87             : 
      88             : #define marker_bit() do { \
      89             :         CHECK(ff_cbs_write_unsigned(ctx, rw, 1, "marker_bit", 1, 1, 1)); \
      90             :     } while (0)
      91             : 
      92             : #define nextbits(width, compare, var) (var)
      93             : 
      94             : #include "cbs_mpeg2_syntax_template.c"
      95             : 
      96             : #undef READ
      97             : #undef READWRITE
      98             : #undef RWContext
      99             : #undef xui
     100             : #undef ui
     101             : #undef marker_bit
     102             : #undef nextbits
     103             : 
     104             : 
     105          14 : static void cbs_mpeg2_free_user_data(void *unit, uint8_t *content)
     106             : {
     107          14 :     MPEG2RawUserData *user = (MPEG2RawUserData*)content;
     108          14 :     av_buffer_unref(&user->user_data_ref);
     109          14 :     av_freep(&content);
     110          14 : }
     111             : 
     112        8746 : static void cbs_mpeg2_free_slice(void *unit, uint8_t *content)
     113             : {
     114        8746 :     MPEG2RawSlice *slice = (MPEG2RawSlice*)content;
     115        8746 :     av_buffer_unref(&slice->header.extra_information_ref);
     116        8746 :     av_buffer_unref(&slice->data_ref);
     117        8746 :     av_freep(&content);
     118        8746 : }
     119             : 
     120          18 : static int cbs_mpeg2_split_fragment(CodedBitstreamContext *ctx,
     121             :                                     CodedBitstreamFragment *frag,
     122             :                                     int header)
     123             : {
     124             :     const uint8_t *start, *end;
     125             :     uint8_t *unit_data;
     126          18 :     uint32_t start_code = -1, next_start_code = -1;
     127             :     size_t unit_size;
     128             :     int err, i, unit_type;
     129             : 
     130          18 :     start = avpriv_find_start_code(frag->data, frag->data + frag->data_size,
     131             :                                    &start_code);
     132        8840 :     for (i = 0;; i++) {
     133       17662 :         end = avpriv_find_start_code(start, frag->data + frag->data_size,
     134             :                                      &next_start_code);
     135             : 
     136        8840 :         unit_type = start_code & 0xff;
     137             : 
     138             :         // The start and end pointers point at to the byte following the
     139             :         // start_code_identifier in the start code that they found.
     140        8840 :         if (end == frag->data + frag->data_size) {
     141             :             // We didn't find a start code, so this is the final unit.
     142          18 :             unit_size = end - (start - 1);
     143             :         } else {
     144             :             // Unit runs from start to the beginning of the start code
     145             :             // pointed to by end (including any padding zeroes).
     146        8822 :             unit_size = (end - 4) - (start - 1);
     147             :         }
     148             : 
     149        8840 :         unit_data = av_malloc(unit_size + AV_INPUT_BUFFER_PADDING_SIZE);
     150        8840 :         if (!unit_data)
     151           0 :             return AVERROR(ENOMEM);
     152        8840 :         memcpy(unit_data, start - 1, unit_size);
     153        8840 :         memset(unit_data + unit_size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
     154             : 
     155        8840 :         err = ff_cbs_insert_unit_data(ctx, frag, i, unit_type,
     156             :                                       unit_data, unit_size, NULL);
     157        8840 :         if (err < 0) {
     158           0 :             av_freep(&unit_data);
     159           0 :             return err;
     160             :         }
     161             : 
     162        8840 :         if (end == frag->data + frag->data_size)
     163          18 :             break;
     164             : 
     165        8822 :         start_code = next_start_code;
     166        8822 :         start = end;
     167             :     }
     168             : 
     169          18 :     return 0;
     170             : }
     171             : 
     172        8840 : static int cbs_mpeg2_read_unit(CodedBitstreamContext *ctx,
     173             :                                CodedBitstreamUnit *unit)
     174             : {
     175             :     GetBitContext gbc;
     176             :     int err;
     177             : 
     178        8840 :     err = init_get_bits(&gbc, unit->data, 8 * unit->data_size);
     179        8840 :     if (err < 0)
     180           0 :         return err;
     181             : 
     182       17586 :     if (MPEG2_START_IS_SLICE(unit->type)) {
     183             :         MPEG2RawSlice *slice;
     184             :         int pos, len;
     185             : 
     186        8746 :         err = ff_cbs_alloc_unit_content(ctx, unit, sizeof(*slice),
     187             :                                         &cbs_mpeg2_free_slice);
     188        8746 :         if (err < 0)
     189           0 :             return err;
     190        8746 :         slice = unit->content;
     191             : 
     192        8746 :         err = cbs_mpeg2_read_slice_header(ctx, &gbc, &slice->header);
     193        8746 :         if (err < 0)
     194           0 :             return err;
     195             : 
     196        8746 :         pos = get_bits_count(&gbc);
     197        8746 :         len = unit->data_size;
     198             : 
     199        8746 :         slice->data_size = len - pos / 8;
     200        8746 :         slice->data_ref  = av_buffer_alloc(slice->data_size +
     201             :                                            AV_INPUT_BUFFER_PADDING_SIZE);
     202        8746 :         if (!slice->data_ref)
     203           0 :             return AVERROR(ENOMEM);
     204        8746 :         slice->data = slice->data_ref->data;
     205             : 
     206       17492 :         memcpy(slice->data,
     207        8746 :                unit->data + pos / 8, slice->data_size);
     208        8746 :         memset(slice->data + slice->data_size, 0,
     209             :                AV_INPUT_BUFFER_PADDING_SIZE);
     210        8746 :         slice->data_bit_start = pos % 8;
     211             : 
     212             :     } else {
     213          94 :         switch (unit->type) {
     214             : #define START(start_code, type, read_func, free_func) \
     215             :         case start_code: \
     216             :             { \
     217             :                 type *header; \
     218             :                 err = ff_cbs_alloc_unit_content(ctx, unit, \
     219             :                                                 sizeof(*header), free_func); \
     220             :                 if (err < 0) \
     221             :                     return err; \
     222             :                 header = unit->content; \
     223             :                 err = cbs_mpeg2_read_ ## read_func(ctx, &gbc, header); \
     224             :                 if (err < 0) \
     225             :                     return err; \
     226             :             } \
     227             :             break;
     228          19 :             START(0x00, MPEG2RawPictureHeader,  picture_header,  NULL);
     229          14 :             START(0xb2, MPEG2RawUserData,       user_data,
     230             :                                             &cbs_mpeg2_free_user_data);
     231           6 :             START(0xb3, MPEG2RawSequenceHeader, sequence_header, NULL);
     232          53 :             START(0xb5, MPEG2RawExtensionData,  extension_data,  NULL);
     233           2 :             START(0xb8, MPEG2RawGroupOfPicturesHeader,
     234             :                                        group_of_pictures_header, NULL);
     235             : #undef START
     236           0 :         default:
     237           0 :             av_log(ctx->log_ctx, AV_LOG_ERROR, "Unknown start code %02"PRIx32".\n",
     238             :                    unit->type);
     239           0 :             return AVERROR_INVALIDDATA;
     240             :         }
     241             :     }
     242             : 
     243        8840 :     return 0;
     244             : }
     245             : 
     246          94 : static int cbs_mpeg2_write_header(CodedBitstreamContext *ctx,
     247             :                                   CodedBitstreamUnit *unit,
     248             :                                   PutBitContext *pbc)
     249             : {
     250             :     int err;
     251             : 
     252          94 :     switch (unit->type) {
     253             : #define START(start_code, type, func) \
     254             :     case start_code: \
     255             :         err = cbs_mpeg2_write_ ## func(ctx, pbc, unit->content); \
     256             :         break;
     257          19 :         START(0x00, MPEG2RawPictureHeader,  picture_header);
     258          14 :         START(0xb2, MPEG2RawUserData,       user_data);
     259           6 :         START(0xb3, MPEG2RawSequenceHeader, sequence_header);
     260          53 :         START(0xb5, MPEG2RawExtensionData,  extension_data);
     261           2 :         START(0xb8, MPEG2RawGroupOfPicturesHeader, group_of_pictures_header);
     262             : #undef START
     263           0 :     default:
     264           0 :         av_log(ctx->log_ctx, AV_LOG_ERROR, "Write unimplemented for start "
     265             :                "code %02"PRIx32".\n", unit->type);
     266           0 :         return AVERROR_PATCHWELCOME;
     267             :     }
     268             : 
     269          94 :     return err;
     270             : }
     271             : 
     272        8746 : static int cbs_mpeg2_write_slice(CodedBitstreamContext *ctx,
     273             :                                  CodedBitstreamUnit *unit,
     274             :                                  PutBitContext *pbc)
     275             : {
     276        8746 :     MPEG2RawSlice *slice = unit->content;
     277             :     GetBitContext gbc;
     278             :     size_t bits_left;
     279             :     int err;
     280             : 
     281        8746 :     err = cbs_mpeg2_write_slice_header(ctx, pbc, &slice->header);
     282        8746 :     if (err < 0)
     283           0 :         return err;
     284             : 
     285        8746 :     if (slice->data) {
     286        8746 :         if (slice->data_size * 8 + 8 > put_bits_left(pbc))
     287           0 :             return AVERROR(ENOSPC);
     288             : 
     289        8746 :         init_get_bits(&gbc, slice->data, slice->data_size * 8);
     290        8746 :         skip_bits_long(&gbc, slice->data_bit_start);
     291             : 
     292      678746 :         while (get_bits_left(&gbc) > 15)
     293      661254 :             put_bits(pbc, 16, get_bits(&gbc, 16));
     294             : 
     295        8746 :         bits_left = get_bits_left(&gbc);
     296        8746 :         put_bits(pbc, bits_left, get_bits(&gbc, bits_left));
     297             : 
     298             :         // Align with zeroes.
     299       17492 :         while (put_bits_count(pbc) % 8 != 0)
     300           0 :             put_bits(pbc, 1, 0);
     301             :     }
     302             : 
     303        8746 :     return 0;
     304             : }
     305             : 
     306        8840 : static int cbs_mpeg2_write_unit(CodedBitstreamContext *ctx,
     307             :                                 CodedBitstreamUnit *unit)
     308             : {
     309        8840 :     CodedBitstreamMPEG2Context *priv = ctx->priv_data;
     310             :     PutBitContext pbc;
     311             :     int err;
     312             : 
     313        8840 :     if (!priv->write_buffer) {
     314             :         // Initial write buffer size is 1MB.
     315           3 :         priv->write_buffer_size = 1024 * 1024;
     316             : 
     317           3 :     reallocate_and_try_again:
     318           3 :         err = av_reallocp(&priv->write_buffer, priv->write_buffer_size);
     319           3 :         if (err < 0) {
     320           0 :             av_log(ctx->log_ctx, AV_LOG_ERROR, "Unable to allocate a "
     321             :                    "sufficiently large write buffer (last attempt "
     322             :                    "%"SIZE_SPECIFIER" bytes).\n", priv->write_buffer_size);
     323           0 :             return err;
     324             :         }
     325             :     }
     326             : 
     327        8840 :     init_put_bits(&pbc, priv->write_buffer, priv->write_buffer_size);
     328             : 
     329        8840 :     if (unit->type >= 0x01 && unit->type <= 0xaf)
     330        8746 :         err = cbs_mpeg2_write_slice(ctx, unit, &pbc);
     331             :     else
     332          94 :         err = cbs_mpeg2_write_header(ctx, unit, &pbc);
     333             : 
     334        8840 :     if (err == AVERROR(ENOSPC)) {
     335             :         // Overflow.
     336           0 :         priv->write_buffer_size *= 2;
     337           0 :         goto reallocate_and_try_again;
     338             :     }
     339        8840 :     if (err < 0) {
     340             :         // Write failed for some other reason.
     341           0 :         return err;
     342             :     }
     343             : 
     344        8840 :     if (put_bits_count(&pbc) % 8)
     345          52 :         unit->data_bit_padding = 8 - put_bits_count(&pbc) % 8;
     346             :     else
     347        8788 :         unit->data_bit_padding = 0;
     348             : 
     349        8840 :     unit->data_size = (put_bits_count(&pbc) + 7) / 8;
     350        8840 :     flush_put_bits(&pbc);
     351             : 
     352        8840 :     err = ff_cbs_alloc_unit_data(ctx, unit, unit->data_size);
     353        8840 :     if (err < 0)
     354           0 :         return err;
     355             : 
     356        8840 :     memcpy(unit->data, priv->write_buffer, unit->data_size);
     357             : 
     358        8840 :     return 0;
     359             : }
     360             : 
     361          18 : static int cbs_mpeg2_assemble_fragment(CodedBitstreamContext *ctx,
     362             :                                        CodedBitstreamFragment *frag)
     363             : {
     364             :     uint8_t *data;
     365             :     size_t size, dp, sp;
     366             :     int i;
     367             : 
     368          18 :     size = 0;
     369        8858 :     for (i = 0; i < frag->nb_units; i++)
     370        8840 :         size += 3 + frag->units[i].data_size;
     371             : 
     372          18 :     frag->data_ref = av_buffer_alloc(size);
     373          18 :     if (!frag->data_ref)
     374           0 :         return AVERROR(ENOMEM);
     375          18 :     data = frag->data_ref->data;
     376             : 
     377          18 :     dp = 0;
     378        8858 :     for (i = 0; i < frag->nb_units; i++) {
     379        8840 :         CodedBitstreamUnit *unit = &frag->units[i];
     380             : 
     381        8840 :         data[dp++] = 0;
     382        8840 :         data[dp++] = 0;
     383        8840 :         data[dp++] = 1;
     384             : 
     385     1362980 :         for (sp = 0; sp < unit->data_size; sp++)
     386     1354140 :             data[dp++] = unit->data[sp];
     387             :     }
     388             : 
     389          18 :     av_assert0(dp == size);
     390             : 
     391          18 :     frag->data      = data;
     392          18 :     frag->data_size = size;
     393             : 
     394          18 :     return 0;
     395             : }
     396             : 
     397           3 : static void cbs_mpeg2_close(CodedBitstreamContext *ctx)
     398             : {
     399           3 :     CodedBitstreamMPEG2Context *priv = ctx->priv_data;
     400             : 
     401           3 :     av_freep(&priv->write_buffer);
     402           3 : }
     403             : 
     404             : const CodedBitstreamType ff_cbs_type_mpeg2 = {
     405             :     .codec_id          = AV_CODEC_ID_MPEG2VIDEO,
     406             : 
     407             :     .priv_data_size    = sizeof(CodedBitstreamMPEG2Context),
     408             : 
     409             :     .split_fragment    = &cbs_mpeg2_split_fragment,
     410             :     .read_unit         = &cbs_mpeg2_read_unit,
     411             :     .write_unit        = &cbs_mpeg2_write_unit,
     412             :     .assemble_fragment = &cbs_mpeg2_assemble_fragment,
     413             : 
     414             :     .close             = &cbs_mpeg2_close,
     415             : };

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