| /* |
| * Copyright (C) 2010 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "include/avc_utils.h" |
| |
| #include <media/stagefright/foundation/ABitReader.h> |
| #include <media/stagefright/foundation/ADebug.h> |
| |
| namespace android { |
| |
| unsigned parseUE(ABitReader *br) { |
| unsigned numZeroes = 0; |
| while (br->getBits(1) == 0) { |
| ++numZeroes; |
| } |
| |
| unsigned x = br->getBits(numZeroes); |
| |
| return x + (1u << numZeroes) - 1; |
| } |
| |
| // Determine video dimensions from the sequence parameterset. |
| void FindAVCDimensions( |
| const sp<ABuffer> &seqParamSet, int32_t *width, int32_t *height) { |
| ABitReader br(seqParamSet->data() + 1, seqParamSet->size() - 1); |
| |
| unsigned profile_idc = br.getBits(8); |
| br.skipBits(16); |
| parseUE(&br); // seq_parameter_set_id |
| |
| unsigned chroma_format_idc = 1; // 4:2:0 chroma format |
| |
| if (profile_idc == 100 || profile_idc == 110 |
| || profile_idc == 122 || profile_idc == 244 |
| || profile_idc == 44 || profile_idc == 83 || profile_idc == 86) { |
| chroma_format_idc = parseUE(&br); |
| if (chroma_format_idc == 3) { |
| br.skipBits(1); // residual_colour_transform_flag |
| } |
| parseUE(&br); // bit_depth_luma_minus8 |
| parseUE(&br); // bit_depth_chroma_minus8 |
| br.skipBits(1); // qpprime_y_zero_transform_bypass_flag |
| CHECK_EQ(br.getBits(1), 0u); // seq_scaling_matrix_present_flag |
| } |
| |
| parseUE(&br); // log2_max_frame_num_minus4 |
| unsigned pic_order_cnt_type = parseUE(&br); |
| |
| if (pic_order_cnt_type == 0) { |
| parseUE(&br); // log2_max_pic_order_cnt_lsb_minus4 |
| } else if (pic_order_cnt_type == 1) { |
| // offset_for_non_ref_pic, offset_for_top_to_bottom_field and |
| // offset_for_ref_frame are technically se(v), but since we are |
| // just skipping over them the midpoint does not matter. |
| |
| br.getBits(1); // delta_pic_order_always_zero_flag |
| parseUE(&br); // offset_for_non_ref_pic |
| parseUE(&br); // offset_for_top_to_bottom_field |
| |
| unsigned num_ref_frames_in_pic_order_cnt_cycle = parseUE(&br); |
| for (unsigned i = 0; i < num_ref_frames_in_pic_order_cnt_cycle; ++i) { |
| parseUE(&br); // offset_for_ref_frame |
| } |
| } |
| |
| parseUE(&br); // num_ref_frames |
| br.getBits(1); // gaps_in_frame_num_value_allowed_flag |
| |
| unsigned pic_width_in_mbs_minus1 = parseUE(&br); |
| unsigned pic_height_in_map_units_minus1 = parseUE(&br); |
| unsigned frame_mbs_only_flag = br.getBits(1); |
| |
| *width = pic_width_in_mbs_minus1 * 16 + 16; |
| |
| *height = (2 - frame_mbs_only_flag) |
| * (pic_height_in_map_units_minus1 * 16 + 16); |
| |
| if (!frame_mbs_only_flag) { |
| br.getBits(1); // mb_adaptive_frame_field_flag |
| } |
| |
| br.getBits(1); // direct_8x8_inference_flag |
| |
| if (br.getBits(1)) { // frame_cropping_flag |
| unsigned frame_crop_left_offset = parseUE(&br); |
| unsigned frame_crop_right_offset = parseUE(&br); |
| unsigned frame_crop_top_offset = parseUE(&br); |
| unsigned frame_crop_bottom_offset = parseUE(&br); |
| |
| unsigned cropUnitX, cropUnitY; |
| if (chroma_format_idc == 0 /* monochrome */) { |
| cropUnitX = 1; |
| cropUnitY = 2 - frame_mbs_only_flag; |
| } else { |
| unsigned subWidthC = (chroma_format_idc == 3) ? 1 : 2; |
| unsigned subHeightC = (chroma_format_idc == 1) ? 2 : 1; |
| |
| cropUnitX = subWidthC; |
| cropUnitY = subHeightC * (2 - frame_mbs_only_flag); |
| } |
| |
| LOGV("frame_crop = (%u, %u, %u, %u), cropUnitX = %u, cropUnitY = %u", |
| frame_crop_left_offset, frame_crop_right_offset, |
| frame_crop_top_offset, frame_crop_bottom_offset, |
| cropUnitX, cropUnitY); |
| |
| *width -= |
| (frame_crop_left_offset + frame_crop_right_offset) * cropUnitX; |
| *height -= |
| (frame_crop_top_offset + frame_crop_bottom_offset) * cropUnitY; |
| } |
| } |
| |
| } // namespace android |
| |