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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#include "AV1FmtpParser.h"
#include <charconv>
#include "api/video_codecs/av1_profile.h"
#include "mozilla/CheckedInt.h"
#include "mozilla/Maybe.h"
#include "nsContentTypeParser.h"
namespace mozilla {
// Whether aLevelIdx is one of the AV1 Annex A.3 levels with defined
// parameters, or level-idx 31 ("Maximum parameters"). Levels 2.2, 2.3, 3.2,
// 3.3, 4.2, 4.3 and 7.0-7.3 are named but have no defined parameters, and
// 24-30 are reserved.
static bool IsDefinedAV1LevelIdx(uint8_t aLevelIdx) {
switch (aLevelIdx) {
case 0:
case 1:
case 4:
case 5:
case 8:
case 9:
case 12:
case 13:
case 14:
case 15:
case 16:
case 17:
case 18:
case 19:
case 31:
return true;
default:
return false;
}
}
// Strict decimal parse: digits only, no sign, whitespace or trailing junk.
static Maybe<uint8_t> ParseUint8(const nsAString& aStr) {
const NS_ConvertUTF16toUTF8 narrow(aStr);
const char* end = narrow.EndReading();
uint8_t value;
const auto [ptr, ec] = std::from_chars(narrow.BeginReading(), end, value);
if (ec != std::errc() || ptr != end) {
return Nothing();
}
return Some(value);
}
AV1FmtpParams ParseAV1Fmtp(const nsACString& aMimeString) {
AV1FmtpParams out;
nsContentTypeParser parser((NS_ConvertUTF8toUTF16(aMimeString)));
nsAutoString profile;
if (NS_SUCCEEDED(parser.GetParameter("profile", profile))) {
NS_ConvertUTF16toUTF8 narrow(profile);
auto parsed = webrtc::StringToAV1Profile(narrow.get());
if (parsed) {
out.mProfile = static_cast<uint8_t>(*parsed);
} else {
out.mProfile = Err(AV1FmtpParseError::Invalid);
}
}
nsAutoString levelIdx;
if (NS_SUCCEEDED(parser.GetParameter("level-idx", levelIdx))) {
Maybe<uint8_t> level = ParseUint8(levelIdx);
if (level && IsDefinedAV1LevelIdx(*level)) {
out.mLevelIdx = *level;
} else {
out.mLevelIdx = Err(AV1FmtpParseError::Invalid);
}
}
nsAutoString tier;
if (NS_SUCCEEDED(parser.GetParameter("tier", tier))) {
Maybe<uint8_t> t = ParseUint8(tier);
if (t && *t <= 1) {
out.mTier = *t;
} else {
out.mTier = Err(AV1FmtpParseError::Invalid);
}
}
return out;
}
namespace {
struct AV1LevelConstraint {
uint8_t mLevelIdx;
uint32_t mMaxPicSize;
uint32_t mMaxHSize;
uint32_t mMaxVSize;
uint64_t mMaxDisplayRate;
};
} // namespace
// AV1 spec Annex A.3 "Levels" table (MaxPicSize/MaxHSize/MaxVSize/
// MaxDisplayRate columns). Only levels with defined parameters are listed;
// levels 2.2, 2.3, 3.2, 3.3, 4.2, 4.3 and 7.0-7.3 (level-idx 2, 3, 6, 7, 10,
// 11, 20-23) have no defined parameters and are intentionally absent, as are
// the reserved 24-30.
static constexpr AV1LevelConstraint kAV1LevelConstraints[] = {
{0, 147456, 2048, 1152, 4423680}, // 2.0
{1, 278784, 2816, 1584, 8363520}, // 2.1
{4, 665856, 4352, 2448, 19975680}, // 3.0
{5, 1065024, 5504, 3096, 31950720}, // 3.1
{8, 2359296, 6144, 3456, 70778880}, // 4.0
{9, 2359296, 6144, 3456, 141557760}, // 4.1
{12, 8912896, 8192, 4352, 267386880}, // 5.0
{13, 8912896, 8192, 4352, 534773760}, // 5.1
{14, 8912896, 8192, 4352, 1069547520}, // 5.2
{15, 8912896, 8192, 4352, 1069547520}, // 5.3
{16, 35651584, 16384, 8704, 1069547520}, // 6.0
{17, 35651584, 16384, 8704, 2139095040}, // 6.1
{18, 35651584, 16384, 8704, 4278190080}, // 6.2
{19, 35651584, 16384, 8704, 4278190080}, // 6.3
};
Maybe<AV1BlockLimits> AV1BlockLimitsForLevel(uint8_t aLevelIdx) {
if (aLevelIdx == 31) {
// "Maximum parameters" -- no limits imposed.
return Nothing();
}
for (const auto& c : kAV1LevelConstraints) {
if (c.mLevelIdx == aLevelIdx) {
// Convert samples to 16x16-pixel blocks, the unit
// VideoEncodingConstraints::maxFs/maxMbps use.
return Some(AV1BlockLimits{c.mMaxPicSize / 256, c.mMaxDisplayRate / 256});
}
}
return Nothing();
}
bool AV1LevelFits(uint8_t aLevelIdx, uint32_t aWidth, uint32_t aHeight,
double aFramerate) {
if (aLevelIdx == 31) {
// "Maximum parameters" -- no limits imposed.
return true;
}
for (const auto& c : kAV1LevelConstraints) {
if (c.mLevelIdx != aLevelIdx) {
continue;
}
if (aWidth > c.mMaxHSize || aHeight > c.mMaxVSize) {
return false;
}
const CheckedInt<uint64_t> picSize =
CheckedInt<uint64_t>(aWidth) * CheckedInt<uint64_t>(aHeight);
if (!picSize.isValid() || picSize.value() > c.mMaxPicSize) {
return false;
}
if (static_cast<double>(picSize.value()) * aFramerate >
static_cast<double>(c.mMaxDisplayRate)) {
return false;
}
return true;
}
return false;
}
} // namespace mozilla