Andreas Huber | 85f12e9 | 2010-08-19 10:39:47 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2010 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #include "include/avc_utils.h" |
| 18 | |
| 19 | #include <media/stagefright/foundation/ABitReader.h> |
| 20 | #include <media/stagefright/foundation/ADebug.h> |
| 21 | |
| 22 | namespace android { |
| 23 | |
Andreas Huber | 6a63a93 | 2010-10-01 10:51:41 -0700 | [diff] [blame] | 24 | unsigned parseUE(ABitReader *br) { |
Andreas Huber | 85f12e9 | 2010-08-19 10:39:47 -0700 | [diff] [blame] | 25 | unsigned numZeroes = 0; |
| 26 | while (br->getBits(1) == 0) { |
| 27 | ++numZeroes; |
| 28 | } |
| 29 | |
| 30 | unsigned x = br->getBits(numZeroes); |
| 31 | |
| 32 | return x + (1u << numZeroes) - 1; |
| 33 | } |
| 34 | |
| 35 | // Determine video dimensions from the sequence parameterset. |
| 36 | void FindAVCDimensions( |
| 37 | const sp<ABuffer> &seqParamSet, int32_t *width, int32_t *height) { |
| 38 | ABitReader br(seqParamSet->data() + 1, seqParamSet->size() - 1); |
| 39 | |
| 40 | unsigned profile_idc = br.getBits(8); |
| 41 | br.skipBits(16); |
| 42 | parseUE(&br); // seq_parameter_set_id |
| 43 | |
Andreas Huber | 2d511ff | 2010-10-08 10:38:39 -0700 | [diff] [blame^] | 44 | unsigned chroma_format_idc = 1; // 4:2:0 chroma format |
| 45 | |
Andreas Huber | 85f12e9 | 2010-08-19 10:39:47 -0700 | [diff] [blame] | 46 | if (profile_idc == 100 || profile_idc == 110 |
| 47 | || profile_idc == 122 || profile_idc == 244 |
| 48 | || profile_idc == 44 || profile_idc == 83 || profile_idc == 86) { |
Andreas Huber | 2d511ff | 2010-10-08 10:38:39 -0700 | [diff] [blame^] | 49 | chroma_format_idc = parseUE(&br); |
Andreas Huber | 85f12e9 | 2010-08-19 10:39:47 -0700 | [diff] [blame] | 50 | if (chroma_format_idc == 3) { |
| 51 | br.skipBits(1); // residual_colour_transform_flag |
| 52 | } |
| 53 | parseUE(&br); // bit_depth_luma_minus8 |
| 54 | parseUE(&br); // bit_depth_chroma_minus8 |
| 55 | br.skipBits(1); // qpprime_y_zero_transform_bypass_flag |
| 56 | CHECK_EQ(br.getBits(1), 0u); // seq_scaling_matrix_present_flag |
| 57 | } |
| 58 | |
| 59 | parseUE(&br); // log2_max_frame_num_minus4 |
| 60 | unsigned pic_order_cnt_type = parseUE(&br); |
| 61 | |
| 62 | if (pic_order_cnt_type == 0) { |
| 63 | parseUE(&br); // log2_max_pic_order_cnt_lsb_minus4 |
| 64 | } else if (pic_order_cnt_type == 1) { |
| 65 | // offset_for_non_ref_pic, offset_for_top_to_bottom_field and |
| 66 | // offset_for_ref_frame are technically se(v), but since we are |
| 67 | // just skipping over them the midpoint does not matter. |
| 68 | |
| 69 | br.getBits(1); // delta_pic_order_always_zero_flag |
| 70 | parseUE(&br); // offset_for_non_ref_pic |
| 71 | parseUE(&br); // offset_for_top_to_bottom_field |
| 72 | |
| 73 | unsigned num_ref_frames_in_pic_order_cnt_cycle = parseUE(&br); |
| 74 | for (unsigned i = 0; i < num_ref_frames_in_pic_order_cnt_cycle; ++i) { |
| 75 | parseUE(&br); // offset_for_ref_frame |
| 76 | } |
| 77 | } |
| 78 | |
| 79 | parseUE(&br); // num_ref_frames |
| 80 | br.getBits(1); // gaps_in_frame_num_value_allowed_flag |
| 81 | |
| 82 | unsigned pic_width_in_mbs_minus1 = parseUE(&br); |
| 83 | unsigned pic_height_in_map_units_minus1 = parseUE(&br); |
| 84 | unsigned frame_mbs_only_flag = br.getBits(1); |
| 85 | |
| 86 | *width = pic_width_in_mbs_minus1 * 16 + 16; |
| 87 | |
| 88 | *height = (2 - frame_mbs_only_flag) |
| 89 | * (pic_height_in_map_units_minus1 * 16 + 16); |
Andreas Huber | 2d511ff | 2010-10-08 10:38:39 -0700 | [diff] [blame^] | 90 | |
| 91 | if (!frame_mbs_only_flag) { |
| 92 | br.getBits(1); // mb_adaptive_frame_field_flag |
| 93 | } |
| 94 | |
| 95 | br.getBits(1); // direct_8x8_inference_flag |
| 96 | |
| 97 | if (br.getBits(1)) { // frame_cropping_flag |
| 98 | unsigned frame_crop_left_offset = parseUE(&br); |
| 99 | unsigned frame_crop_right_offset = parseUE(&br); |
| 100 | unsigned frame_crop_top_offset = parseUE(&br); |
| 101 | unsigned frame_crop_bottom_offset = parseUE(&br); |
| 102 | |
| 103 | unsigned cropUnitX, cropUnitY; |
| 104 | if (chroma_format_idc == 0 /* monochrome */) { |
| 105 | cropUnitX = 1; |
| 106 | cropUnitY = 2 - frame_mbs_only_flag; |
| 107 | } else { |
| 108 | unsigned subWidthC = (chroma_format_idc == 3) ? 1 : 2; |
| 109 | unsigned subHeightC = (chroma_format_idc == 1) ? 2 : 1; |
| 110 | |
| 111 | cropUnitX = subWidthC; |
| 112 | cropUnitY = subHeightC * (2 - frame_mbs_only_flag); |
| 113 | } |
| 114 | |
| 115 | LOGV("frame_crop = (%u, %u, %u, %u), cropUnitX = %u, cropUnitY = %u", |
| 116 | frame_crop_left_offset, frame_crop_right_offset, |
| 117 | frame_crop_top_offset, frame_crop_bottom_offset, |
| 118 | cropUnitX, cropUnitY); |
| 119 | |
| 120 | *width -= |
| 121 | (frame_crop_left_offset + frame_crop_right_offset) * cropUnitX; |
| 122 | *height -= |
| 123 | (frame_crop_top_offset + frame_crop_bottom_offset) * cropUnitY; |
| 124 | } |
Andreas Huber | 85f12e9 | 2010-08-19 10:39:47 -0700 | [diff] [blame] | 125 | } |
| 126 | |
| 127 | } // namespace android |
| 128 | |