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Allow reading compressed subtitles from mkv

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The error handling inside of read_subtitles is a bit clumsy here,
but it's probably the best we can get without bigger refactors.
This commit is contained in:
arch1t3cht 2023-10-25 20:20:04 +02:00
parent 644a4ca9f7
commit 2ac3bdf870
1 changed files with 49 additions and 7 deletions
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56
src/mkv_wrap.cpp
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@ -114,19 +114,49 @@ struct MkvStdIO final : InputStream {
}
};
static void read_subtitles(agi::ProgressSink *ps, MatroskaFile *file, MkvStdIO *input, bool srt, double totalTime, AssParser *parser) {
static bool read_subtitles(agi::ProgressSink *ps, MatroskaFile *file, MkvStdIO *input, bool srt, double totalTime, AssParser *parser, CompressedStream *cs) {
std::vector<std::pair<int, std::string>> subList;
// Load blocks
uint64_t startTime, endTime, filePos;
unsigned int rt, frameSize, frameFlags;
std::vector<char> uncompBuf(cs ? 256 : 0);
while (mkv_ReadFrame(file, 0, &rt, &startTime, &endTime, &filePos, &frameSize, &frameFlags) == 0) {
if (ps->IsCancelled()) return;
if (ps->IsCancelled()) return true;
if (frameSize == 0) continue;
const auto readBuf = input->file.read(filePos, frameSize);
const auto readBufEnd = readBuf + frameSize;
const char *readBuf;
const char *readBufEnd;
if (cs) {
cs_NextFrame(cs, filePos, frameSize);
int bytesRead = 0;
int res;
do {
res = cs_ReadData(cs, &uncompBuf[bytesRead], uncompBuf.size() - bytesRead);
if (res == -1) {
const char *err = cs_GetLastError(cs);
if (!err) err = "Unknown error";
ps->Log("Failed to decompress subtitles: " + std::string(err));
ps->SetStayOpen(true);
return false;
}
bytesRead += res;
if (bytesRead >= uncompBuf.size())
uncompBuf.resize(2 * uncompBuf.size());
} while (res != 0);
readBuf = &uncompBuf[0];
readBufEnd = readBuf + bytesRead;
} else {
readBuf = input->file.read(filePos, frameSize);
readBufEnd = readBuf + frameSize;
}
// Get start and end times
int64_t timecodeScaleLow = 1000000;
@ -170,6 +200,7 @@ static void read_subtitles(agi::ProgressSink *ps, MatroskaFile *file, MkvStdIO *
sort(begin(subList), end(subList));
for (auto order_value_pair : subList)
parser->AddLine(order_value_pair.second);
return true;
}
void MatroskaWrapper::GetSubtitles(agi::fs::path const& filename, AssFile *target) {
@ -186,7 +217,7 @@ void MatroskaWrapper::GetSubtitles(agi::fs::path const& filename, AssFile *targe
// Find tracks
for (auto track : boost::irange(0u, tracks)) {
auto trackInfo = mkv_GetTrackInfo(file, track);
if (trackInfo->Type != 0x11 || trackInfo->CompEnabled) continue;
if (trackInfo->Type != 0x11) continue;
// Known subtitle format
std::string CodecID(trackInfo->CodecID);
@ -242,6 +273,13 @@ void MatroskaWrapper::GetSubtitles(agi::fs::path const& filename, AssFile *targe
parser.AddLine("[Events]");
agi::scoped_holder<CompressedStream *, decltype(&cs_Destroy)> cs(nullptr, cs_Destroy);
if (trackInfo->CompEnabled) {
cs = cs_Create(file, trackToRead, err, sizeof(err));
if (!cs)
throw MatroskaException(err);
}
// Read timecode scale
auto segInfo = mkv_GetFileInfo(file);
int64_t timecodeScale = mkv_TruncFloat(trackInfo->TimecodeScale) * segInfo->TimecodeScale;
@ -249,7 +287,11 @@ void MatroskaWrapper::GetSubtitles(agi::fs::path const& filename, AssFile *targe
// Progress bar
auto totalTime = double(segInfo->Duration) / timecodeScale;
DialogProgress progress(nullptr, _("Parsing Matroska"), _("Reading subtitles from Matroska file."));
progress.Run([&](agi::ProgressSink *ps) { read_subtitles(ps, file, &input, srt, totalTime, &parser); });
bool result;
progress.Run([&](agi::ProgressSink *ps) { result = read_subtitles(ps, file, &input, srt, totalTime, &parser, cs); });
if (!result)
throw MatroskaException("Failed to read subtitles");
}
bool MatroskaWrapper::HasSubtitles(agi::fs::path const& filename) {
@ -264,7 +306,7 @@ bool MatroskaWrapper::HasSubtitles(agi::fs::path const& filename) {
for (auto track : boost::irange(0u, tracks)) {
auto trackInfo = mkv_GetTrackInfo(file, track);
if (trackInfo->Type == 0x11 && !trackInfo->CompEnabled) {
if (trackInfo->Type == 0x11) {
std::string CodecID(trackInfo->CodecID);
if (CodecID == "S_TEXT/SSA" || CodecID == "S_TEXT/ASS" || CodecID == "S_TEXT/UTF8")
return true;