cbs_mpeg2: Add support for picture display extension

libavcodec/cbs_mpeg2.h

@@ -160,6 +160,11 @@ typedef struct MPEG2RawQuantMatrixExtension {
     uint8_t chroma_non_intra_quantiser_matrix[64];
 } MPEG2RawQuantMatrixExtension;
 
+typedef struct MPEG2RawPictureDisplayExtension {
+    uint16_t frame_centre_horizontal_offset[3];
+    uint16_t frame_centre_vertical_offset[3];
+} MPEG2RawPictureDisplayExtension;
+
 typedef struct MPEG2RawExtensionData {
     uint8_t extension_start_code;
     uint8_t extension_start_code_identifier;
@@ -169,6 +174,7 @@ typedef struct MPEG2RawExtensionData {
         MPEG2RawSequenceDisplayExtension sequence_display;
         MPEG2RawQuantMatrixExtension quant_matrix;
         MPEG2RawPictureCodingExtension picture_coding;
+        MPEG2RawPictureDisplayExtension picture_display;
     } data;
 } MPEG2RawExtensionData;
 
@@ -206,6 +212,8 @@ typedef struct CodedBitstreamMPEG2Context {
     uint16_t vertical_size;
     uint8_t scalable;
     uint8_t scalable_mode;
+    uint8_t progressive_sequence;
+    uint8_t number_of_frame_centre_offsets;
 
     // Write buffer.
     uint8_t *write_buffer;

libavcodec/cbs_mpeg2_syntax_template.c

@@ -101,6 +101,7 @@ static int FUNC(sequence_extension)(CodedBitstreamContext *ctx, RWContext *rw,
         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();
@@ -183,6 +184,7 @@ static int FUNC(picture_header)(CodedBitstreamContext *ctx, RWContext *rw,
 static int FUNC(picture_coding_extension)(CodedBitstreamContext *ctx, RWContext *rw,
                                           MPEG2RawPictureCodingExtension *current)
 {
+    CodedBitstreamMPEG2Context *mpeg2 = ctx->priv_data;
     int err;
 
     HEADER("Picture Coding Extension");
@@ -204,6 +206,27 @@ static int FUNC(picture_coding_extension)(CodedBitstreamContext *ctx, RWContext
     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);
@@ -250,6 +273,24 @@ static int FUNC(quant_matrix_extension)(CodedBitstreamContext *ctx, RWContext *r
     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++) {
+        ui(16, frame_centre_horizontal_offset[i]);
+        marker_bit();
+        ui(16, frame_centre_vertical_offset[i]);
+        marker_bit();
+    }
+
+    return 0;
+}
+
 static int FUNC(extension_data)(CodedBitstreamContext *ctx, RWContext *rw,
                                 MPEG2RawExtensionData *current)
 {
@@ -270,6 +311,9 @@ static int FUNC(extension_data)(CodedBitstreamContext *ctx, RWContext *rw,
     case 3:
         return FUNC(quant_matrix_extension)
             (ctx, rw, &current->data.quant_matrix);
+    case 7:
+        return FUNC(picture_display_extension)
+            (ctx, rw, &current->data.picture_display);
     case 8:
         return FUNC(picture_coding_extension)
             (ctx, rw, &current->data.picture_coding);