/*
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 static int FUNC(sequence_header)(CodedBitstreamContext *ctx, RWContext *rw,
                                  MPEG2RawSequenceHeader *current)
 {
     CodedBitstreamMPEG2Context *mpeg2 = ctx->priv_data;
     int err, i;
 
     HEADER("Sequence Header");
 
     ui(8,  sequence_header_code);
 

     uir(12, horizontal_size_value);
     uir(12, vertical_size_value);

 
     mpeg2->horizontal_size = current->horizontal_size_value;
     mpeg2->vertical_size   = current->vertical_size_value;
 

     uir(4, aspect_ratio_information);
     uir(4, frame_rate_code);

     ui(18, bit_rate_value);
 
     marker_bit();
 
     ui(10, vbv_buffer_size_value);
     ui(1,  constrained_parameters_flag);
 
     ui(1, load_intra_quantiser_matrix);
     if (current->load_intra_quantiser_matrix) {
         for (i = 0; i < 64; i++)

             uirs(8, intra_quantiser_matrix[i], 1, i);

     }
 
     ui(1, load_non_intra_quantiser_matrix);
     if (current->load_non_intra_quantiser_matrix) {
         for (i = 0; i < 64; i++)

             uirs(8, non_intra_quantiser_matrix[i], 1, i);

     }
 
     return 0;
 }
 
 static int FUNC(user_data)(CodedBitstreamContext *ctx, RWContext *rw,
                            MPEG2RawUserData *current)
 {
     size_t k;
     int err;
 
     HEADER("User Data");
 
     ui(8, user_data_start_code);
 
 #ifdef READ
     k = get_bits_left(rw);
     av_assert0(k % 8 == 0);
     current->user_data_length = k /= 8;
     if (k > 0) {

         current->user_data_ref = av_buffer_allocz(k + AV_INPUT_BUFFER_PADDING_SIZE);

         if (!current->user_data_ref)

             return AVERROR(ENOMEM);

         current->user_data = current->user_data_ref->data;

     }
 #endif
 
     for (k = 0; k < current->user_data_length; k++)

         uis(8, user_data[k], 1, k);

 
     return 0;
 }
 
 static int FUNC(sequence_extension)(CodedBitstreamContext *ctx, RWContext *rw,
                                     MPEG2RawSequenceExtension *current)
 {
     CodedBitstreamMPEG2Context *mpeg2 = ctx->priv_data;
     int err;
 
     HEADER("Sequence Extension");
 
     ui(8,  profile_and_level_indication);
     ui(1,  progressive_sequence);
     ui(2,  chroma_format);
     ui(2,  horizontal_size_extension);
     ui(2,  vertical_size_extension);
 
     mpeg2->horizontal_size = (mpeg2->horizontal_size & 0xfff) |
         current->horizontal_size_extension << 12;
     mpeg2->vertical_size = (mpeg2->vertical_size & 0xfff) |
         current->vertical_size_extension << 12;
     mpeg2->progressive_sequence = current->progressive_sequence;
 
     ui(12, bit_rate_extension);
     marker_bit();
     ui(8,  vbv_buffer_size_extension);
     ui(1,  low_delay);
     ui(2,  frame_rate_extension_n);
     ui(5,  frame_rate_extension_d);
 
     return 0;
 }
 
 static int FUNC(sequence_display_extension)(CodedBitstreamContext *ctx, RWContext *rw,
                                             MPEG2RawSequenceDisplayExtension *current)
 {
     int err;
 
     HEADER("Sequence Display Extension");
 
     ui(3, video_format);
 
     ui(1, colour_description);
     if (current->colour_description) {

 #ifdef READ
 #define READ_AND_PATCH(name) do { \
         ui(8, name); \
         if (current->name == 0) { \
             current->name = 2; \
             av_log(ctx->log_ctx, AV_LOG_WARNING, "%s in a sequence display " \
                    "extension had the invalid value 0. Setting it to 2 " \
                    "(meaning unknown) instead.\n", #name); \
         } \
     } while (0)
         READ_AND_PATCH(colour_primaries);
         READ_AND_PATCH(transfer_characteristics);
         READ_AND_PATCH(matrix_coefficients);
 #undef READ_AND_PATCH
 #else
         uir(8, colour_primaries);
         uir(8, transfer_characteristics);
         uir(8, matrix_coefficients);
 #endif

     }
 
     ui(14, display_horizontal_size);
     marker_bit();
     ui(14, display_vertical_size);
 
     return 0;
 }
 
 static int FUNC(group_of_pictures_header)(CodedBitstreamContext *ctx, RWContext *rw,
                                           MPEG2RawGroupOfPicturesHeader *current)
 {
     int err;
 
     HEADER("Group of Pictures Header");
 
     ui(8,  group_start_code);
 
     ui(25, time_code);
     ui(1,  closed_gop);
     ui(1,  broken_link);
 
     return 0;
 }
 
 static int FUNC(picture_header)(CodedBitstreamContext *ctx, RWContext *rw,
                                 MPEG2RawPictureHeader *current)
 {
     int err;
 
     HEADER("Picture Header");
 
     ui(8,  picture_start_code);
 
     ui(10, temporal_reference);

     uir(3, picture_coding_type);

     ui(16, vbv_delay);
 
     if (current->picture_coding_type == 2 ||
         current->picture_coding_type == 3) {
         ui(1, full_pel_forward_vector);
         ui(3, forward_f_code);
     }
 
     if (current->picture_coding_type == 3) {
         ui(1, full_pel_backward_vector);
         ui(3, backward_f_code);
     }
 
     ui(1, extra_bit_picture);
 
     return 0;
 }
 
 static int FUNC(picture_coding_extension)(CodedBitstreamContext *ctx, RWContext *rw,
                                           MPEG2RawPictureCodingExtension *current)
 {
     CodedBitstreamMPEG2Context *mpeg2 = ctx->priv_data;
     int err;
 
     HEADER("Picture Coding Extension");
 

     uir(4, f_code[0][0]);
     uir(4, f_code[0][1]);
     uir(4, f_code[1][0]);
     uir(4, f_code[1][1]);

 
     ui(2, intra_dc_precision);
     ui(2, picture_structure);
     ui(1, top_field_first);
     ui(1, frame_pred_frame_dct);
     ui(1, concealment_motion_vectors);
     ui(1, q_scale_type);
     ui(1, intra_vlc_format);
     ui(1, alternate_scan);
     ui(1, repeat_first_field);
     ui(1, chroma_420_type);
     ui(1, progressive_frame);
 
     if (mpeg2->progressive_sequence) {
         if (current->repeat_first_field) {
             if (current->top_field_first)
                 mpeg2->number_of_frame_centre_offsets = 3;
             else
                 mpeg2->number_of_frame_centre_offsets = 2;
         } else {
             mpeg2->number_of_frame_centre_offsets = 1;
         }
     } else {
         if (current->picture_structure == 1 || // Top field.
             current->picture_structure == 2) { // Bottom field.
             mpeg2->number_of_frame_centre_offsets = 1;
         } else {
             if (current->repeat_first_field)
                 mpeg2->number_of_frame_centre_offsets = 3;
             else
                 mpeg2->number_of_frame_centre_offsets = 2;
         }
     }
 
     ui(1, composite_display_flag);
     if (current->composite_display_flag) {
         ui(1, v_axis);
         ui(3, field_sequence);
         ui(1, sub_carrier);
         ui(7, burst_amplitude);
         ui(8, sub_carrier_phase);
     }
 
     return 0;
 }
 
 static int FUNC(quant_matrix_extension)(CodedBitstreamContext *ctx, RWContext *rw,
                                         MPEG2RawQuantMatrixExtension *current)
 {
     int err, i;
 
     HEADER("Quant Matrix Extension");
 
     ui(1, load_intra_quantiser_matrix);
     if (current->load_intra_quantiser_matrix) {
         for (i = 0; i < 64; i++)

             uirs(8, intra_quantiser_matrix[i], 1, i);

     }
 
     ui(1, load_non_intra_quantiser_matrix);
     if (current->load_non_intra_quantiser_matrix) {
         for (i = 0; i < 64; i++)

             uirs(8, non_intra_quantiser_matrix[i], 1, i);

     }
 
     ui(1, load_chroma_intra_quantiser_matrix);
     if (current->load_chroma_intra_quantiser_matrix) {
         for (i = 0; i < 64; i++)

             uirs(8, intra_quantiser_matrix[i], 1, i);

     }
 
     ui(1, load_chroma_non_intra_quantiser_matrix);
     if (current->load_chroma_non_intra_quantiser_matrix) {
         for (i = 0; i < 64; i++)

             uirs(8, chroma_non_intra_quantiser_matrix[i], 1, i);

     }
 
     return 0;
 }
 
 static int FUNC(picture_display_extension)(CodedBitstreamContext *ctx, RWContext *rw,
                                            MPEG2RawPictureDisplayExtension *current)
 {
     CodedBitstreamMPEG2Context *mpeg2 = ctx->priv_data;
     int err, i;
 
     HEADER("Picture Display Extension");
 
     for (i = 0; i < mpeg2->number_of_frame_centre_offsets; i++) {

         sis(16, frame_centre_horizontal_offset[i], 1, i);

         marker_bit();

         sis(16, frame_centre_vertical_offset[i],   1, i);

         marker_bit();
     }
 
     return 0;
 }
 
 static int FUNC(extension_data)(CodedBitstreamContext *ctx, RWContext *rw,
                                 MPEG2RawExtensionData *current)
 {
     int err;
 
     HEADER("Extension Data");
 
     ui(8, extension_start_code);
     ui(4, extension_start_code_identifier);
 
     switch (current->extension_start_code_identifier) {

     case MPEG2_EXTENSION_SEQUENCE:

         return FUNC(sequence_extension)
             (ctx, rw, &current->data.sequence);

     case MPEG2_EXTENSION_SEQUENCE_DISPLAY:

         return FUNC(sequence_display_extension)
             (ctx, rw, &current->data.sequence_display);

     case MPEG2_EXTENSION_QUANT_MATRIX:

         return FUNC(quant_matrix_extension)
             (ctx, rw, &current->data.quant_matrix);

     case MPEG2_EXTENSION_PICTURE_DISPLAY:

         return FUNC(picture_display_extension)
             (ctx, rw, &current->data.picture_display);

     case MPEG2_EXTENSION_PICTURE_CODING:

         return FUNC(picture_coding_extension)
             (ctx, rw, &current->data.picture_coding);
     default:

         av_log(ctx->log_ctx, AV_LOG_ERROR, "Extension ID %d not supported.\n",

                current->extension_start_code_identifier);

         return AVERROR_PATCHWELCOME;

     }
 }
 
 static int FUNC(slice_header)(CodedBitstreamContext *ctx, RWContext *rw,
                               MPEG2RawSliceHeader *current)
 {
     CodedBitstreamMPEG2Context *mpeg2 = ctx->priv_data;
     int err;
 
     HEADER("Slice Header");
 
     ui(8, slice_vertical_position);
 
     if (mpeg2->vertical_size > 2800)
         ui(3, slice_vertical_position_extension);
     if (mpeg2->scalable) {
         if (mpeg2->scalable_mode == 0)
             ui(7, priority_breakpoint);
     }
 

     uir(5, quantiser_scale_code);

 
     if (nextbits(1, 1, current->slice_extension_flag)) {
         ui(1, slice_extension_flag);
         ui(1, intra_slice);
         ui(1, slice_picture_id_enable);
         ui(6, slice_picture_id);
 
         {
             size_t k;
 #ifdef READ
             GetBitContext start;
             uint8_t bit;
             start = *rw;
             for (k = 0; nextbits(1, 1, bit); k++)
                 skip_bits(rw, 8);
             current->extra_information_length = k;
             if (k > 0) {
                 *rw = start;

                 current->extra_information_ref =
                     av_buffer_alloc(current->extra_information_length);
                 if (!current->extra_information_ref)

                     return AVERROR(ENOMEM);

                 current->extra_information = current->extra_information_ref->data;

                 for (k = 0; k < current->extra_information_length; k++) {

                     xui(1, extra_bit_slice, bit, 1, 1, 0);

                     xui(8, extra_information_slice[k],

                         current->extra_information[k], 0, 255, 1, k);

                 }
             }
 #else
             for (k = 0; k < current->extra_information_length; k++) {

                 xui(1, extra_bit_slice, 1, 1, 1, 0);

                 xui(8, extra_information_slice[k],

                     current->extra_information[k], 0, 255, 1, k);

             }
 #endif
         }
     }
     ui(1, extra_bit_slice);
 
     return 0;
 }