Fix error on creating cut videos; fill any shortfall in audio with silence.

diff --git a/src/lib/decoder.cc b/src/lib/decoder.cc
index fd7992febbe997d038bd963e039a9d37b5053e7d..38de4e3a159ebc21163a9dfb2dbcc389811e2f5a 100644 (file)
--- a/src/lib/decoder.cc
+++ b/src/lib/decoder.cc
@@ -70,6 +70,7 @@ Decoder::Decoder (boost::shared_ptr<const FilmState> s, boost::shared_ptr<const
        , _have_setup_video_filters (false)
        , _delay_line (0)
        , _delay_in_bytes (0)
+       , _audio_frames_processed (0)
 {
        if (_opt->decode_video_frequency != 0 && _fs->length == 0) {
                throw DecodeError ("cannot do a partial decode if length == 0");
@@ -88,6 +89,8 @@ Decoder::process_begin ()
        _delay_in_bytes = _fs->audio_delay * _fs->audio_sample_rate * _fs->audio_channels * 2 / 1000;
        delete _delay_line;
        _delay_line = new DelayLine (_delay_in_bytes);
+
+       _audio_frames_processed = 0;
 }
 
 void
@@ -96,8 +99,27 @@ Decoder::process_end ()
        if (_delay_in_bytes < 0) {
                uint8_t remainder[-_delay_in_bytes];
                _delay_line->get_remaining (remainder);
+               _audio_frames_processed += _delay_in_bytes / (audio_channels() * 2);
                Audio (remainder, _delay_in_bytes);
        }
+
+       /* If we cut the decode off, the audio may be short; push some silence
+          in to get it to the right length.
+       */
+
+       int const audio_short_by_frames = (decoding_frames() * _fs->audio_sample_rate / _fs->frames_per_second) - _audio_frames_processed;
+
+       int bytes = audio_short_by_frames * audio_channels() * 2;
+
+       int const silence_size = 64 * 1024;
+       uint8_t silence[silence_size];
+       memset (silence, 0, silence_size);
+
+       while (bytes) {
+               int const t = min (bytes, silence_size);
+               Audio (silence, t);
+               bytes -= t;
+       }
 }
 
 /** Start decoding */
@@ -153,6 +175,11 @@ Decoder::pass ()
 void
 Decoder::process_audio (uint8_t* data, int channels, int size)
 {
+       /* Update the number of audio frames we've pushed to the encoder;
+          2 is the hard-coded (!) number of bytes per sample.
+       */
+       _audio_frames_processed += size / (channels * 2);
+               
        if (_fs->audio_gain != 0) {
                float const linear_gain = pow (10, _fs->audio_gain / 20);
                uint8_t* p = data;

diff --git a/src/lib/decoder.h b/src/lib/decoder.h
index db51879a17d29e74b611d2d1cba0c4562eab966a..d8551047043f08af5c84b01259a45035bad8d790 100644 (file)
--- a/src/lib/decoder.h
+++ b/src/lib/decoder.h
@@ -131,6 +131,8 @@ private:
        bool _have_setup_video_filters;
        DelayLine* _delay_line;
        int _delay_in_bytes;
+
+       int _audio_frames_processed;
 };
 
 #endif