ffmpeg: bypass ass encoding for srt

Fixes #1927

app/codec/ffmpeg/ffmpegdecoder.cpp

@@ -425,34 +425,13 @@ FootageDescription FFmpegDecoder::Probe(const QString &filename, const QAtomicIn
               Instance instance;
               instance.Open(filename_c, avstream->index);
 
-              //qDebug() << instance.GetSubtitleHeader();
+              while (instance.GetPacket(pkt) >= 0) {
+                TimeRange time(Timecode::timestamp_to_time(pkt->pts, avstream->time_base),
+                               Timecode::timestamp_to_time(pkt->pts + pkt->duration, avstream->time_base));
 
-              AVSubtitle avsub;
-              while (instance.GetSubtitle(pkt, &avsub) >= 0) {
-                for (unsigned int j=0; j<avsub.num_rects; j++) {
-                  QString ass = avsub.rects[j]->ass;
+                QString text = QString::fromUtf8((const char *) pkt->data, pkt->size);
 
-                  int comma = 0;
-                  for (int k=0; k<ass.size(); k++) {
-                    if (ass.at(k) == ',') {
-                      comma++;
-                    }
-
-                    // HARDCODED: I think FFmpeg always puts the text of SRTs in the 8th section
-                    if (comma == 8) {
-                      ass = ass.mid(k+1);
-                      break;
-                    }
-                  }
-
-                  ass.replace(QStringLiteral("\\n"), QStringLiteral("\n"), Qt::CaseInsensitive);
-
-                  TimeRange time(Timecode::timestamp_to_time(pkt->pts, avstream->time_base),
-                                 Timecode::timestamp_to_time(pkt->pts + pkt->duration, avstream->time_base));
-
-                  sub.push_back(Subtitle(time, ass));
-                }
-                avsubtitle_free(&avsub);
+                sub.push_back(Subtitle(time, text));
               }
 
               instance.Close();
@@ -1132,13 +1111,7 @@ int FFmpegDecoder::Instance::GetFrame(AVPacket *pkt, AVFrame *frame)
   while ((ret = avcodec_receive_frame(codec_ctx_, frame)) == AVERROR(EAGAIN) && !eof) {
 
     // Find next packet in the correct stream index
-    do {
-      // Free buffer in packet if there is one
-      av_packet_unref(pkt);
-
-      // Read packet from file
-      ret = av_read_frame(fmt_ctx_, pkt);
-    } while (pkt->stream_index != avstream_->index && ret >= 0);
+    ret = GetPacket(pkt);
 
     if (ret == AVERROR_EOF) {
       // Don't break so that receive gets called again, but don't try to read again
@@ -1172,13 +1145,7 @@ const char *FFmpegDecoder::Instance::GetSubtitleHeader() const
 
 int FFmpegDecoder::Instance::GetSubtitle(AVPacket *pkt, AVSubtitle *sub)
 {
-  int ret;
-
-  do {
-    av_packet_unref(pkt);
-
-    ret = av_read_frame(fmt_ctx_, pkt);
-  } while (pkt->stream_index != avstream_->index && ret >= 0);
+  int ret = GetPacket(pkt);
 
   if (ret >= 0) {
     int got_sub;
@@ -1191,6 +1158,19 @@ int FFmpegDecoder::Instance::GetSubtitle(AVPacket *pkt, AVSubtitle *sub)
   return ret;
 }
 
+int FFmpegDecoder::Instance::GetPacket(AVPacket *pkt)
+{
+  int ret;
+
+  do {
+    av_packet_unref(pkt);
+
+    ret = av_read_frame(fmt_ctx_, pkt);
+  } while (pkt->stream_index != avstream_->index && ret >= 0);
+
+  return ret;
+}
+
 void FFmpegDecoder::Instance::Seek(int64_t timestamp)
 {
   avcodec_flush_buffers(codec_ctx_);

app/codec/ffmpeg/ffmpegdecoder.h

@@ -95,6 +95,8 @@ private:
 
     int GetSubtitle(AVPacket* pkt, AVSubtitle* sub);
 
+    int GetPacket(AVPacket *pkt);
+
     void Seek(int64_t timestamp);
 
     AVFormatContext* fmt_ctx() const

app/codec/ffmpeg/ffmpegencoder.cpp

@@ -376,46 +376,15 @@ QString GetAssTime(const rational &time)
 
 bool FFmpegEncoder::WriteSubtitle(const SubtitleBlock *sub_block)
 {
-  AVSubtitle subtitle;
-  memset(&subtitle, 0, sizeof(subtitle));
-
-  AVSubtitleRect rect;
-  memset(&rect, 0, sizeof(rect));
-
-  QString ass_line = QStringLiteral("Dialogue: 0,%1,%2,Default,,0,0,0,,%3").arg(
-        GetAssTime(sub_block->in()),
-        GetAssTime(sub_block->out()),
-        sub_block->GetText()
-      );
-
   QByteArray utf8_sub = sub_block->GetText().toUtf8();
-  QByteArray utf8_ass = ass_line.toUtf8();
-
-  rect.type = SUBTITLE_ASS;
-  rect.text = utf8_sub.data();
-  rect.ass = utf8_ass.data();
-
-  AVSubtitleRect *rect_array = ▭
-  subtitle.num_rects = 1;
-  subtitle.rects = &rect_array;
-
-  subtitle.pts = Timecode::time_to_timestamp(sub_block->in(), subtitle_codec_ctx_->time_base, Timecode::kFloor);
-  subtitle.end_display_time = qRound64(sub_block->length().toDouble() * 1000);
-
-  QVector<uint8_t> out_buf(1024 * 1024);
-
-  int sub_sz = avcodec_encode_subtitle(subtitle_codec_ctx_, out_buf.data(), out_buf.size(), &subtitle);
-  if (sub_sz < 0) {
-    return false;
-  }
 
   AVPacket *pkt = av_packet_alloc();
 
   pkt->stream_index = subtitle_stream_->index;
-  pkt->data = out_buf.data();
-  pkt->size = sub_sz;
-  pkt->pts = subtitle.pts;
-  pkt->duration = av_rescale_q(subtitle.end_display_time, {1, 1000}, subtitle_codec_ctx_->time_base);
+  pkt->data = (uint8_t *) utf8_sub.data();
+  pkt->size = utf8_sub.size();
+  pkt->pts = Timecode::time_to_timestamp(sub_block->in(), subtitle_codec_ctx_->time_base, Timecode::kFloor);
+  pkt->duration = av_rescale_q(qRound64(sub_block->length().toDouble() * 1000), {1, 1000}, subtitle_codec_ctx_->time_base);
   pkt->dts = pkt->pts;
   av_packet_rescale_ts(pkt, subtitle_codec_ctx_->time_base, subtitle_stream_->time_base);