Closes #162: If not present, add time stamps to the copied streams

HISTORY.md

@@ -4,6 +4,8 @@ History
 **New in 2.17 (2024-08-XX):**
 
 - **Bugfix:** Wrong error message fixed when an invalid audio/video codec was selected. The message should rather say "unsupported codec" instead of talking about "sample format not supported.".
+- **Bugfix:** Issue [#162](https://github.com/nschlia/ffmpegfs/issues/162): If not present, add time stamps to the copied streams.
+
 **New in 2.16 (2024-06-10):**
 
 - **Bugfix:** Issue [#160](https://github.com/nschlia/ffmpegfs/issues/160): Fix build with FFmpeg 7.0. [Debian Bug #1072412](https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1072412). write_packet() now with const buffer as of Libavformat 61+.

NEWS

@@ -5,6 +5,7 @@ Important changes in 2.17 (2024-08-XX):
 * Bugfix: Wrong error message fixed when an invalid audio/video codec was
   selected. The message should rather say "unsupported codec" instead of
   talking about "sample format not supported.".
+* Bugfix: Issue #162: If not present, add time stamps to the copied streams.
 
 Important changes in 2.16 (2024-06-10):
 

README.md

@@ -35,6 +35,7 @@ To see what's been done so far, checkout the [windows](https://github.com/nschli
 **New in 2.17 (2024-08-XX):**
 
 - **Bugfix:** Wrong error message fixed when an invalid audio/video codec was selected. The message should rather say "unsupported codec" instead of talking about "sample format not supported.".
+- **Bugfix:** Issue [#162](https://github.com/nschlia/ffmpegfs/issues/162): If not present, add time stamps to the copied streams.
 
 **New in 2.16 (2024-06-10):**
 

src/ffmpeg_transcoder.cc

@@ -235,6 +235,8 @@ FFmpeg_Transcoder::FFmpeg_Transcoder()
     , m_insert_keyframe(true)
     , m_copy_audio(false)
     , m_copy_video(false)
+    , m_cur_audio_ts(0)
+    , m_cur_video_ts(0)
     , m_current_format(nullptr)
     , m_buffer(nullptr)
     , m_reset_pts(0)
@@ -3745,6 +3747,33 @@ int FFmpeg_Transcoder::store_packet(AVPacket *pkt, AVMediaType mediatype)
     return ret;
 }
 
+void FFmpeg_Transcoder::make_pts(AVPacket *pkt, int64_t *cur_ts) const
+{
+    if (pkt->pts != AV_NOPTS_VALUE)
+    {
+        *cur_ts = pkt->pts + pkt->duration;
+    }
+    else if (pkt->dts != AV_NOPTS_VALUE)
+    {
+        *cur_ts = pkt->dts;
+    }
+
+    if (pkt->duration)
+    {
+        if (pkt->pts == AV_NOPTS_VALUE)
+        {
+            pkt->pts            = *cur_ts;
+        }
+
+        *cur_ts += pkt->duration;
+
+        if (pkt->dts == AV_NOPTS_VALUE)
+        {
+            pkt->dts            = *cur_ts;
+        }
+    }
+}
+
 int FFmpeg_Transcoder::decode_frame(AVPacket *pkt)
 {
     int ret = 0;
@@ -3771,18 +3800,13 @@ int FFmpeg_Transcoder::decode_frame(AVPacket *pkt)
         {
             // Simply copy packet without recoding
             pkt->stream_index   = m_out.m_audio.m_stream_idx;
-            if (pkt->pts != AV_NOPTS_VALUE)
-            {
-                pkt->pts            = ffmpeg_rescale_q_rnd(pkt->pts, m_in.m_audio.m_stream->time_base, m_out.m_audio.m_stream->time_base);
-            }
-            if (pkt->dts != AV_NOPTS_VALUE)
-            {
-                pkt->dts            = ffmpeg_rescale_q_rnd(pkt->dts, m_in.m_audio.m_stream->time_base, m_out.m_audio.m_stream->time_base);
-            }
-            if (pkt->duration)
-            {
-                pkt->duration       = static_cast<int>(ffmpeg_rescale_q(pkt->duration, m_in.m_audio.m_stream->time_base, m_out.m_audio.m_stream->time_base));
-            }
+
+            // Rescale packet
+            av_packet_rescale_ts(pkt, m_in.m_audio.m_stream->time_base, m_out.m_audio.m_stream->time_base);
+
+            // Make PTS/DTS if missing
+            make_pts(pkt, &m_cur_audio_ts);
+
             pkt->pos            = -1;
 
             ret = store_packet(pkt, AVMEDIA_TYPE_AUDIO);
@@ -3859,7 +3883,13 @@ int FFmpeg_Transcoder::decode_frame(AVPacket *pkt)
         {
             // Simply copy packet without recoding
             pkt->stream_index   = m_out.m_video.m_stream_idx;
+
+            // Rescale packet
             av_packet_rescale_ts(pkt, m_in.m_video.m_stream->time_base, m_out.m_video.m_stream->time_base);
+
+            // Make PTS/DTS if missing
+            make_pts(pkt, &m_cur_video_ts);
+
             pkt->pos            = -1;
 
             ret = store_packet(pkt, AVMEDIA_TYPE_VIDEO);

src/ffmpeg_transcoder.h

@@ -635,6 +635,14 @@ class FFmpeg_Transcoder : public FFmpeg_Base, FFmpeg_Profiles
      * @return On success, returns 0; on error, a negative AVERROR value.
      */
     int                         decode_subtitle(AVCodecContext *codec_ctx, AVPacket *pkt, int *decoded, int out_stream_idx);
+    /**
+     * @brief Create PTS/DTS and update the packet.
+     * If the update packet lacks time stamps, create a fictitious PTS or DTS and update it.
+     * If the packet already has valid time stamps, nothing is changed.
+     * @param[inout] pkt - Audio/video packet to update.
+     * @param[inout] cur_ts - Current time stamp, will be updated to the next position.
+     */
+    void                        make_pts(AVPacket *pkt, int64_t *cur_ts) const;
     /**
      * @brief Decode one frame.
      * @param[in] pkt - Packet to decode.
@@ -1251,6 +1259,10 @@ class FFmpeg_Transcoder : public FFmpeg_Base, FFmpeg_Profiles
     bool                        m_copy_audio;                   /**< @brief If true, copy audio stream from source to target (just remux, no recode). */
     bool                        m_copy_video;                   /**< @brief If true, copy video stream from source to target (just remux, no recode). */
 
+    // Time stamps
+    int64_t                     m_cur_audio_ts;                 /**< @brief If the audio stream is copied and the time stamps are absent from the input stream, we have to generate them. */
+    int64_t                     m_cur_video_ts;                 /**< @brief If the video stream is copied and the time stamps are absent from the input stream, we have to generate them. */
+
     const FFmpegfs_Format *     m_current_format;               /**< @brief Currently used output format(s) */
 
     Buffer *                    m_buffer;                       /**< @brief Pointer to cache buffer object */