ac3parse: add support for "audio/x-private1-ac3"

This commit is contained in:
Andoni Morales Alastruey 2013-05-02 14:56:02 +02:00
parent 53da901cc9
commit 4531381541
2 changed files with 66 additions and 7 deletions

View file

@ -35,7 +35,7 @@
*/
/* TODO:
* - add support for audio/x-private1-ac3 as well
* - audio/ac3 to audio/x-private1-ac3 is not implemented (done in the muxer)
* - should accept framed and unframed input (needs decodebin fixes first)
*/
@ -153,7 +153,8 @@ static GstStaticPadTemplate src_template = GST_STATIC_PAD_TEMPLATE ("src",
static GstStaticPadTemplate sink_template = GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("audio/x-ac3; " "audio/x-eac3; " "audio/ac3"));
GST_STATIC_CAPS ("audio/x-ac3; " "audio/x-eac3; " "audio/ac3; "
"audio/x-private1-ac3"));
static void gst_ac3_parse_finalize (GObject * object);
@ -165,6 +166,8 @@ static gboolean gst_ac3_parse_src_event (GstBaseParse * parse,
GstEvent * event);
static GstCaps *gst_ac3_parse_get_sink_caps (GstBaseParse * parse,
GstCaps * filter);
static gboolean gst_ac3_parse_set_sink_caps (GstBaseParse * parse,
GstCaps * caps);
#define gst_ac3_parse_parent_class parent_class
G_DEFINE_TYPE (GstAc3Parse, gst_ac3_parse, GST_TYPE_BASE_PARSE);
@ -195,6 +198,7 @@ gst_ac3_parse_class_init (GstAc3ParseClass * klass)
parse_class->handle_frame = GST_DEBUG_FUNCPTR (gst_ac3_parse_handle_frame);
parse_class->src_event = GST_DEBUG_FUNCPTR (gst_ac3_parse_src_event);
parse_class->get_sink_caps = GST_DEBUG_FUNCPTR (gst_ac3_parse_get_sink_caps);
parse_class->set_sink_caps = GST_DEBUG_FUNCPTR (gst_ac3_parse_set_sink_caps);
}
static void
@ -212,6 +216,8 @@ gst_ac3_parse_init (GstAc3Parse * ac3parse)
{
gst_base_parse_set_min_frame_size (GST_BASE_PARSE (ac3parse), 6);
gst_ac3_parse_reset (ac3parse);
ac3parse->baseparse_chainfunc =
GST_BASE_PARSE_SINK_PAD (GST_BASE_PARSE (ac3parse))->chainfunc;
}
static void
@ -660,6 +666,43 @@ cleanup:
return res;
}
/*
* MPEG-PS private1 streams add a 2 bytes "Audio Substream Headers" for each
* buffer (not each frame) with the offset of the next frame's start.
*
* Buffer 1:
* -------------------------------------------
* |firstAccUnit|AC3SyncWord|xxxxxxxxxxxxxxxxx
* -------------------------------------------
* Buffer 2:
* -------------------------------------------
* |firstAccUnit|xxxxxx|AC3SyncWord|xxxxxxxxxx
* -------------------------------------------
*
* These 2 bytes can be dropped safely as they do not include any timing
* information, only the offset to the start of the next frame.
*
* From http://stnsoft.com/DVD/ass-hdr.html:
* "FirstAccUnit offset to frame which corresponds to PTS value offset 0 is the
* last byte of FirstAccUnit, ie add the offset of byte 2 to get the AU's offset
* The value 0000 indicates there is no first access unit"
* */
static GstFlowReturn
gst_ac3_parse_chain_priv (GstPad * pad, GstObject * parent, GstBuffer * buffer)
{
GstBuffer *newbuf;
GstFlowReturn ret;
GstAc3Parse *ac3parse = GST_AC3_PARSE (parent);
newbuf = gst_buffer_copy_region (buffer, GST_BUFFER_COPY_ALL,
2, gst_buffer_get_size (buffer) - 2);
ret = ac3parse->baseparse_chainfunc (pad, parent, newbuf);
gst_buffer_unref (buffer);
return ret;
}
static gboolean
gst_ac3_parse_src_event (GstBaseParse * parse, GstEvent * event)
{
@ -737,3 +780,18 @@ gst_ac3_parse_get_sink_caps (GstBaseParse * parse, GstCaps * filter)
return res;
}
static gboolean
gst_ac3_parse_set_sink_caps (GstBaseParse * parse, GstCaps * caps)
{
GstStructure *s;
GstAc3Parse *ac3parse = GST_AC3_PARSE (parse);
s = gst_caps_get_structure (caps, 0);
if (gst_structure_has_name (s, "audio/x-private1-ac3")) {
gst_pad_set_chain_function (parse->sinkpad, gst_ac3_parse_chain_priv);
} else {
gst_pad_set_chain_function (parse->sinkpad, ac3parse->baseparse_chainfunc);
}
return TRUE;
}

View file

@ -57,11 +57,12 @@ struct _GstAc3Parse {
GstBaseParse baseparse;
/*< private >*/
gint sample_rate;
gint channels;
gint blocks;
gboolean eac;
volatile gint align;
gint sample_rate;
gint channels;
gint blocks;
gboolean eac;
volatile gint align;
GstPadChainFunction baseparse_chainfunc;
};
/**