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mpegtsmux: generate SPS/PPS header once and fix overflow

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Some H264 packets can be as small as 5 bytes for repeated frames.
In such a situation the output buffer size was not big enough (5*2) to fit the
SPS/PPS header and the start codes. This corrupts the ES stream.
We now generate the SPS/PPS only once which is much more optimal and we now
know the size of the header to calculate the output buffer size more safely.
This commit is contained in:
Julien Moutte 2010-02-02 12:23:24 +01:00
parent 934c91682f
commit 6f1ee59df6
4 changed files with 170 additions and 67 deletions
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9
gst/mpegtsmux/mpegtsmux.c
View file

@ -1,5 +1,5 @@
/*
* Copyright 2006, 2007, 2008 Fluendo S.A.
* Copyright 2006, 2007, 2008, 2009, 2010 Fluendo S.A.
* Authors: Jan Schmidt <jan@fluendo.com>
* Kapil Agrawal <kapil@fluendo.com>
* Julien Moutte <julien@fluendo.com>
@ -350,6 +350,7 @@ mpegtsmux_create_stream (MpegTsMux * mux, MpegTsPadData * ts_data, GstPad * pad)
GST_DEBUG_OBJECT (pad, "we have additional codec data (%d bytes)",
GST_BUFFER_SIZE (ts_data->codec_data));
ts_data->prepare_func = mpegtsmux_prepare_h264;
ts_data->free_func = mpegtsmux_free_h264;
} else {
ts_data->codec_data = NULL;
}
@ -713,7 +714,9 @@ mpegtsmux_request_new_pad (GstElement * element,
pad_data->pid = pid;
pad_data->last_ts = GST_CLOCK_TIME_NONE;
pad_data->codec_data = NULL;
pad_data->prepare_data = NULL;
pad_data->prepare_func = NULL;
pad_data->free_func = NULL;
pad_data->prog_id = -1;
pad_data->prog = NULL;
@ -757,6 +760,10 @@ mpegtsmux_release_pad (GstElement * element, GstPad * pad)
gst_buffer_unref (pad_data->codec_data);
pad_data->codec_data = NULL;
}
if (pad_data->prepare_data && pad_data->free_func) {
pad_data->free_func (pad_data->prepare_data);
pad_data->prepare_data = pad_data->free_func = NULL;
}
}
GST_OBJECT_UNLOCK (pad);

8
gst/mpegtsmux/mpegtsmux.h
View file

@ -1,5 +1,5 @@
/*
* Copyright 2006, 2007, 2008 Fluendo S.A.
* Copyright 2006, 2007, 2008, 2009, 2010 Fluendo S.A.
* Authors: Jan Schmidt <jan@fluendo.com>
* Kapil Agrawal <kapil@fluendo.com>
* Julien Moutte <julien@fluendo.com>
@ -101,6 +101,8 @@ typedef struct MpegTsPadData MpegTsPadData;
typedef GstBuffer * (*MpegTsPadDataPrepareFunction) (GstBuffer * buf,
MpegTsPadData * data, MpegTsMux * mux);
typedef void (*MpegTsPadDataFreePrepareDataFunction) (gpointer prepare_data);
struct MpegTsMux {
GstElement parent;
@ -140,7 +142,11 @@ struct MpegTsPadData {
GstBuffer * codec_data; /* Optional codec data available in the caps */
gpointer prepare_data; /* Opaque data pointer to a structure used by the
prepare function */
MpegTsPadDataPrepareFunction prepare_func; /* Handler to prepare input data */
MpegTsPadDataFreePrepareDataFunction free_func; /* Handler to free the private data */
gboolean eos;

136
gst/mpegtsmux/mpegtsmux_h264.c
View file

@ -1,5 +1,5 @@
/*
* Copyright 2006, 2007, 2008 Fluendo S.A.
* Copyright 2006, 2007, 2008, 2009, 2010 Fluendo S.A.
* Authors: Jan Schmidt <jan@fluendo.com>
* Kapil Agrawal <kapil@fluendo.com>
* Julien Moutte <julien@fluendo.com>
@ -90,28 +90,71 @@
GST_DEBUG_CATEGORY_EXTERN (mpegtsmux_debug);
#define GST_CAT_DEFAULT mpegtsmux_debug
GstBuffer *
mpegtsmux_prepare_h264 (GstBuffer * buf, MpegTsPadData * data, MpegTsMux * mux)
#define SPS_PPS_PERIOD GST_SECOND
typedef struct PrivDataH264 PrivDataH264;
struct PrivDataH264
{
guint8 nal_length_size = 0;
guint8 startcode[4] = { 0x00, 0x00, 0x00, 0x01 };
GstBuffer *out_buf = gst_buffer_new_and_alloc (GST_BUFFER_SIZE (buf) * 2);
GstBuffer *last_codec_data;
GstClockTime last_resync_ts;
GstBuffer *cached_es;
guint8 nal_length_size;
};
void
mpegtsmux_free_h264 (gpointer prepare_data)
{
PrivDataH264 *h264_data = (PrivDataH264 *) prepare_data;
if (h264_data->cached_es) {
gst_buffer_unref (h264_data->cached_es);
h264_data->cached_es = NULL;
}
g_free (prepare_data);
}
static inline gboolean
mpegtsmux_process_codec_data_h264 (MpegTsPadData * data, MpegTsMux * mux)
{
PrivDataH264 *h264_data;
gboolean ret = FALSE;
/* Initialize our private data structure for caching */
if (G_UNLIKELY (!data->prepare_data)) {
data->prepare_data = g_new0 (PrivDataH264, 1);
h264_data = (PrivDataH264 *) data->prepare_data;
h264_data->last_resync_ts = GST_CLOCK_TIME_NONE;
}
h264_data = (PrivDataH264 *) data->prepare_data;
/* Detect a codec data change */
if (h264_data->last_codec_data != data->codec_data) {
gst_buffer_unref (h264_data->cached_es);
h264_data->cached_es = NULL;
ret = TRUE;
}
/* Generate the SPS/PPS ES header that will be prepended regularly */
if (G_UNLIKELY (!h264_data->cached_es)) {
gint offset = 4, i = 0, nb_sps = 0, nb_pps = 0;
gsize out_offset = 0, in_offset = 0;
GST_DEBUG_OBJECT (mux, "Preparing H264 buffer for output");
/* We want the same metadata */
gst_buffer_copy_metadata (out_buf, buf, GST_BUFFER_COPY_ALL);
gsize out_offset = 0;
guint8 startcode[4] = { 0x00, 0x00, 0x00, 0x01 };
h264_data->last_codec_data = data->codec_data;
h264_data->cached_es =
gst_buffer_new_and_alloc (GST_BUFFER_SIZE (data->codec_data) * 10);
/* Get NAL length size */
nal_length_size =
(GST_READ_UINT8 (GST_BUFFER_DATA (data->codec_data) + offset) & 0x03) + 1;
GST_LOG_OBJECT (mux, "NAL length will be coded on %u bytes", nal_length_size);
h264_data->nal_length_size =
(GST_READ_UINT8 (GST_BUFFER_DATA (data->codec_data) + offset) & 0x03) +
1;
GST_LOG_OBJECT (mux, "NAL length will be coded on %u bytes",
h264_data->nal_length_size);
offset++;
/* Generate SPS */
nb_sps = GST_READ_UINT8 (GST_BUFFER_DATA (data->codec_data) + offset) & 0x1f;
/* How many SPS */
nb_sps =
GST_READ_UINT8 (GST_BUFFER_DATA (data->codec_data) + offset) & 0x1f;
GST_DEBUG_OBJECT (mux, "we have %d Sequence Parameter Set", nb_sps);
offset++;
@ -126,16 +169,18 @@ mpegtsmux_prepare_h264 (GstBuffer * buf, MpegTsPadData * data, MpegTsMux * mux)
offset += 2;
/* Fake a start code */
memcpy (GST_BUFFER_DATA (out_buf) + out_offset, startcode, 4);
memcpy (GST_BUFFER_DATA (h264_data->cached_es) + out_offset,
startcode, 4);
out_offset += 4;
/* Now push the SPS */
memcpy (GST_BUFFER_DATA (out_buf) + out_offset,
memcpy (GST_BUFFER_DATA (h264_data->cached_es) + out_offset,
GST_BUFFER_DATA (data->codec_data) + offset, sps_size);
out_offset += sps_size;
offset += sps_size;
}
/* How many PPS */
nb_pps = GST_READ_UINT8 (GST_BUFFER_DATA (data->codec_data) + offset);
GST_LOG_OBJECT (mux, "we have %d Picture Parameter Set", nb_sps);
offset++;
@ -151,21 +196,64 @@ mpegtsmux_prepare_h264 (GstBuffer * buf, MpegTsPadData * data, MpegTsMux * mux)
offset += 2;
/* Fake a start code */
memcpy (GST_BUFFER_DATA (out_buf) + out_offset, startcode, 4);
memcpy (GST_BUFFER_DATA (h264_data->cached_es) + out_offset,
startcode, 4);
out_offset += 4;
/* Now push the PPS */
memcpy (GST_BUFFER_DATA (out_buf) + out_offset,
memcpy (GST_BUFFER_DATA (h264_data->cached_es) + out_offset,
GST_BUFFER_DATA (data->codec_data) + offset, pps_size);
out_offset += pps_size;
offset += pps_size;
}
GST_BUFFER_SIZE (h264_data->cached_es) = out_offset;
GST_DEBUG_OBJECT (mux, "generated a %" G_GSIZE_FORMAT
" bytes SPS/PPS header", out_offset);
}
return ret;
}
GstBuffer *
mpegtsmux_prepare_h264 (GstBuffer * buf, MpegTsPadData * data, MpegTsMux * mux)
{
guint8 startcode[4] = { 0x00, 0x00, 0x00, 0x01 };
gsize out_offset = 0, in_offset = 0;
GstBuffer *out_buf;
gboolean changed;
PrivDataH264 *h264_data;
GstClockTimeDiff diff = GST_CLOCK_TIME_NONE;
GST_DEBUG_OBJECT (mux, "Preparing H264 buffer for output");
changed = mpegtsmux_process_codec_data_h264 (data, mux);
h264_data = (PrivDataH264 *) data->prepare_data;
if (GST_CLOCK_TIME_IS_VALID (h264_data->last_resync_ts) &&
GST_CLOCK_TIME_IS_VALID (GST_BUFFER_TIMESTAMP (buf))) {
diff = GST_CLOCK_DIFF (h264_data->last_resync_ts,
GST_BUFFER_TIMESTAMP (buf));
}
if (changed || (GST_CLOCK_TIME_IS_VALID (diff) && diff > SPS_PPS_PERIOD)) {
out_buf = gst_buffer_new_and_alloc (GST_BUFFER_SIZE (buf) * 2 +
GST_BUFFER_SIZE (h264_data->cached_es));
h264_data->last_resync_ts = GST_BUFFER_TIMESTAMP (buf);
memcpy (GST_BUFFER_DATA (out_buf), GST_BUFFER_DATA (h264_data->cached_es),
GST_BUFFER_SIZE (h264_data->cached_es));
out_offset = GST_BUFFER_SIZE (h264_data->cached_es);
GST_DEBUG_OBJECT (mux, "prepending SPS/PPS information to that packet");
} else {
out_buf = gst_buffer_new_and_alloc (GST_BUFFER_SIZE (buf) * 2);
}
/* We want the same metadata */
gst_buffer_copy_metadata (out_buf, buf, GST_BUFFER_COPY_ALL);
while (in_offset < GST_BUFFER_SIZE (buf) &&
out_offset < GST_BUFFER_SIZE (out_buf) - 4) {
guint32 nal_size = 0;
switch (nal_length_size) {
switch (h264_data->nal_length_size) {
case 1:
nal_size = GST_READ_UINT8 (GST_BUFFER_DATA (buf) + in_offset);
break;
@ -177,9 +265,9 @@ mpegtsmux_prepare_h264 (GstBuffer * buf, MpegTsPadData * data, MpegTsMux * mux)
break;
default:
GST_WARNING_OBJECT (mux, "unsupported NAL length size %u",
nal_length_size);
h264_data->nal_length_size);
}
in_offset += nal_length_size;
in_offset += h264_data->nal_length_size;
/* Generate an Elementary stream buffer by inserting a startcode */
memcpy (GST_BUFFER_DATA (out_buf) + out_offset, startcode, 4);

4
gst/mpegtsmux/mpegtsmux_h264.h
View file

@ -1,5 +1,5 @@
/*
* Copyright 2006, 2007, 2008 Fluendo S.A.
* Copyright 2006, 2007, 2008, 2009, 2010 Fluendo S.A.
* Authors: Jan Schmidt <jan@fluendo.com>
* Kapil Agrawal <kapil@fluendo.com>
* Julien Moutte <julien@fluendo.com>
@ -88,4 +88,6 @@
GstBuffer * mpegtsmux_prepare_h264 (GstBuffer * buf, MpegTsPadData * data,
MpegTsMux * mux);
void mpegtsmux_free_h264 (gpointer prepare_data);
#endif /* __MPEGTSMUX_H264_H__ */