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mad: helpfully bodge the last buffer to let mad decode the last frame

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If http://www.mars.org/mailman/public/mad-dev/2001-May/000262.html is
to be believed, the last buffer must be followed by a number of 0 bytes
in order for the last frame to be decoded (at least in some cases).
Doing so seems to work here, fixing a missing 1152 samples when using
mp3parse before mad (not using mp3parse would yield the correct amount
of samples, if there's extra non-MP3 data after (eg, tag data)).
This commit is contained in:
Vincent Penquerc'h 2011-12-22 15:23:54 +00:00
parent 20dcefd5c0
commit 30e29b6fdb
2 changed files with 34 additions and 0 deletions
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32
ext/mad/gstmad.c
View file

@ -82,6 +82,7 @@ static gboolean gst_mad_parse (GstAudioDecoder * dec, GstAdapter * adapter,
gint * offset, gint * length);
static GstFlowReturn gst_mad_handle_frame (GstAudioDecoder * dec,
GstBuffer * buffer);
static gboolean gst_mad_event (GstAudioDecoder * dec, GstEvent * event);
static void gst_mad_flush (GstAudioDecoder * dec, gboolean hard);
static void gst_mad_set_property (GObject * object, guint prop_id,
@ -119,6 +120,7 @@ gst_mad_class_init (GstMadClass * klass)
base_class->parse = GST_DEBUG_FUNCPTR (gst_mad_parse);
base_class->handle_frame = GST_DEBUG_FUNCPTR (gst_mad_handle_frame);
base_class->flush = GST_DEBUG_FUNCPTR (gst_mad_flush);
base_class->event = GST_DEBUG_FUNCPTR (gst_mad_event);
gobject_class->set_property = gst_mad_set_property;
gobject_class->get_property = gst_mad_get_property;
@ -168,6 +170,7 @@ gst_mad_start (GstAudioDecoder * dec)
mad_stream_options (&mad->stream, options);
mad->header.mode = -1;
mad->header.emphasis = -1;
mad->eos = FALSE;
/* call upon legacy upstream byte support (e.g. seeking) */
gst_audio_decoder_set_byte_time (dec, TRUE);
@ -282,6 +285,20 @@ gst_mad_parse (GstAudioDecoder * dec, GstAdapter * adapter,
mad = GST_MAD (dec);
if (mad->eos) {
/* This is one steaming hack right there.
* mad will not decode the last frame if it is not followed by
* a number of 0 bytes, due to some buffer overflow, which can
* not be fixed for reasons I did not inquire into, see
* http://www.mars.org/mailman/public/mad-dev/2001-May/000262.html
*/
GstBuffer *guard = gst_buffer_new_and_alloc (MAD_BUFFER_GUARD);
memset (GST_BUFFER_DATA (guard), 0, GST_BUFFER_SIZE (guard));
GST_DEBUG_OBJECT (mad, "Discreetly stuffing %u zero bytes in the adapter",
GST_BUFFER_SIZE (guard));
gst_adapter_push (adapter, guard);
}
/* we basically let mad library do parsing,
* and translate that back to baseclass.
* if a frame is found (and also decoded), subsequent handle_frame
@ -482,6 +499,21 @@ gst_mad_flush (GstAudioDecoder * dec, gboolean hard)
}
}
static gboolean
gst_mad_event (GstAudioDecoder * dec, GstEvent * event)
{
GstMad *mad;
mad = GST_MAD (dec);
if (GST_EVENT_TYPE (event) == GST_EVENT_EOS) {
GST_DEBUG_OBJECT (mad, "We got EOS, will pad next time");
mad->eos = TRUE;
}
/* Let the base class do its usual thing */
return FALSE;
}
static void
gst_mad_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)

2
ext/mad/gstmad.h
View file

@ -63,6 +63,8 @@ struct _GstMad
gint times_pending;
gboolean caps_set; /* used to keep track of whether to change/update caps */
gboolean eos;
/* properties */
gboolean half;
gboolean ignore_crc;