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// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "media/video/h264_level_limits.h"
#include "base/logging.h"
#include "base/numerics/checked_math.h"
#include "media/video/h264_parser.h"
namespace media {
namespace {
struct LevelLimits {
// All names and abbreviations are as in table A-1 in spec.
// MaxMBPS, Max. macroblock processing rate (MB/s)
uint32_t max_mbps;
// MaxFS, Max. frame size (MBs)
uint32_t max_fs;
// MaxDpbMbs, Max. decoded picture buffer size (MBs)
uint32_t max_dpb_mbs;
// MaxBR, Max. video bitrate for Baseline and Main Profiles (kbit/s)
uint32_t max_main_br;
};
LevelLimits LevelToLevelLimits(uint8_t level) {
// See table A-1 in spec
// { MaxMBPS, MaxFS, MaxDpbMbs, MaxBR}
switch (level) {
case H264SPS::kLevelIDC1p0:
return {1485, 99, 396, 64}; // Level 1.0
case H264SPS::kLevelIDC1B:
return {1485, 99, 396, 128}; // Level 1b
case H264SPS::kLevelIDC1p1:
return {3000, 396, 900, 192}; // Level 1.1
case H264SPS::kLevelIDC1p2:
return {6000, 396, 2376, 384}; // Level 1.2
case H264SPS::kLevelIDC1p3:
return {11800, 396, 2376, 768}; // Level 1.3
case H264SPS::kLevelIDC2p0:
return {11880, 396, 2376, 2000}; // Level 2.0
case H264SPS::kLevelIDC2p1:
return {19800, 792, 4752, 4000}; // Level 2.1
case H264SPS::kLevelIDC2p2:
return {20250, 1620, 8100, 4000}; // Level 2.2
case H264SPS::kLevelIDC3p0:
return {40500, 1620, 8100, 10000}; // Level 3.0
case H264SPS::kLevelIDC3p1:
return {108000, 3600, 18000, 14000}; // Level 3.1
case H264SPS::kLevelIDC3p2:
return {216000, 5120, 20480, 20000}; // Level 3.2
case H264SPS::kLevelIDC4p0:
return {245760, 8192, 32768, 20000}; // Level 4.0
case H264SPS::kLevelIDC4p1:
return {245760, 8192, 32768, 50000}; // Level 4.1
case H264SPS::kLevelIDC4p2:
return {522240, 8704, 34816, 50000}; // Level 4.2
case H264SPS::kLevelIDC5p0:
return {589824, 22080, 110400, 135000}; // Level 5.0
case H264SPS::kLevelIDC5p1:
return {983040, 36864, 184320, 240000}; // Level 5.1
case H264SPS::kLevelIDC5p2:
return {2073600, 36864, 184320, 240000}; // Level 5.2
case H264SPS::kLevelIDC6p0:
return {4177920, 139264, 696320, 240000}; // Level 6.0
case H264SPS::kLevelIDC6p1:
return {8355840, 139264, 696320, 480000}; // Level 6.1
case H264SPS::kLevelIDC6p2:
return {16711680, 139264, 696320, 800000}; // Level 6.2
default:
DVLOG(1) << "Invalid codec level (" << static_cast<int>(level) << ")";
return {0, 0, 0, 0};
}
}
} // namespace
uint32_t H264LevelToMaxMBPS(uint8_t level) {
return LevelToLevelLimits(level).max_mbps;
}
uint32_t H264LevelToMaxFS(uint8_t level) {
return LevelToLevelLimits(level).max_fs;
}
uint32_t H264LevelToMaxDpbMbs(uint8_t level) {
return LevelToLevelLimits(level).max_dpb_mbs;
}
uint32_t H264ProfileLevelToMaxBR(VideoCodecProfile profile, uint8_t level) {
uint32_t max_main_br = LevelToLevelLimits(level).max_main_br;
// See table A-2 in spec
// The maximum bit rate for High Profile is 1.25 times that of the
// Base/Extended/Main Profiles, 3 times for Hi10P, and 4 times for
// Hi422P/Hi444PP.
switch (profile) {
case H264PROFILE_BASELINE:
case H264PROFILE_MAIN:
case H264PROFILE_EXTENDED:
return max_main_br;
case H264PROFILE_HIGH:
return max_main_br * 5 / 4;
case H264PROFILE_HIGH10PROFILE:
return max_main_br * 3;
case H264PROFILE_HIGH422PROFILE:
case H264PROFILE_HIGH444PREDICTIVEPROFILE:
return max_main_br * 4;
default:
DVLOG(1) << "Failed to query MaxBR for profile: "
<< GetProfileName(profile);
return 0;
}
}
bool CheckH264LevelLimits(VideoCodecProfile profile,
uint8_t level,
uint32_t bitrate,
uint32_t framerate,
uint32_t framesize_in_mbs) {
uint32_t max_bitrate_kbs = H264ProfileLevelToMaxBR(profile, level);
DCHECK(base::IsValueInRangeForNumericType<uint32_t>(max_bitrate_kbs * 1000));
uint32_t max_bitrate = max_bitrate_kbs * 1000;
if (bitrate > max_bitrate) {
DVLOG(1) << "Target bitrate: " << bitrate << " exceeds Max: " << max_bitrate
<< " bit/s";
return false;
}
if (framesize_in_mbs > H264LevelToMaxFS(level)) {
DVLOG(1) << "Target frame size: " << framesize_in_mbs
<< " exceeds Max: " << H264LevelToMaxFS(level) << " Macroblocks";
return false;
}
uint32_t mbps = framesize_in_mbs * framerate;
if (mbps > H264LevelToMaxMBPS(level)) {
DVLOG(1) << "Target macroblock processing rate: " << mbps
<< " exceeds Max: " << H264LevelToMaxMBPS(level) << "Macroblock/s";
return false;
}
return true;
}
absl::optional<uint8_t> FindValidH264Level(VideoCodecProfile profile,
uint32_t bitrate,
uint32_t framerate,
uint32_t framesize_in_mbs) {
constexpr uint8_t kH264Levels[] = {
H264SPS::kLevelIDC1p0, H264SPS::kLevelIDC1B, H264SPS::kLevelIDC1p1,
H264SPS::kLevelIDC1p2, H264SPS::kLevelIDC1p3, H264SPS::kLevelIDC2p0,
H264SPS::kLevelIDC2p1, H264SPS::kLevelIDC2p2, H264SPS::kLevelIDC3p0,
H264SPS::kLevelIDC3p1, H264SPS::kLevelIDC3p2, H264SPS::kLevelIDC4p0,
H264SPS::kLevelIDC4p1, H264SPS::kLevelIDC4p2, H264SPS::kLevelIDC5p0,
H264SPS::kLevelIDC5p1, H264SPS::kLevelIDC5p2, H264SPS::kLevelIDC6p0,
H264SPS::kLevelIDC6p1, H264SPS::kLevelIDC6p2,
};
for (const uint8_t level : kH264Levels) {
if (CheckH264LevelLimits(profile, level, bitrate, framerate,
framesize_in_mbs)) {
return level;
}
}
return absl::nullopt;
}
} // namespace media
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