Class: GstBase::Adapter

Inherits:
Object
  • Object
show all
Defined in:
(unknown)

Instance Method Summary collapse

Constructor Details

#initialize ⇒ GstBase::Adapter

Creates a new Gst::Adapter. Free with g_object_unref().

Instance Method Details

#available ⇒ Integer

Gets the maximum amount of bytes available, that is it returns the maximum
value that can be supplied to gst_adapter_map() without that function
returning nil.

Returns:

  • (Integer) —

    number of bytes available in adapter

#available_fast ⇒ Integer

Gets the maximum number of bytes that are immediately available without
requiring any expensive operations (like copying the data into a
temporary buffer).
operations

Returns:

  • (Integer) —

    number of bytes that are available in adapter without expensive

#clear ⇒ nil

Removes all buffers from adapter.

Returns:

  • (nil)

#copy(dest, offset, size) ⇒ nil

Copies size bytes of data starting at offset out of the buffers
contained in Gst::Adapter into an array dest provided by the caller.

The array dest should be large enough to contain size bytes.
The user should check that the adapter has (offset + size) bytes
available before calling this function.

Parameters:

  • dest (Array<Integer>) —

    the memory to copy into

  • offset (Integer) —

    the bytes offset in the adapter to start from

  • size (Integer) —

    the number of bytes to copy

Returns:

  • (nil)

#copy_bytes(offset, size) ⇒ GLib::Bytes

Similar to gst_adapter_copy, but more suitable for language bindings. size
bytes of data starting at offset will be copied out of the buffers contained
in adapter and into a new #GBytes structure which is returned. Depending on
the value of the size argument an empty #GBytes structure may be returned.

Parameters:

  • offset (Integer) —

    the bytes offset in the adapter to start from

  • size (Integer) —

    the number of bytes to copy

Returns:

  • (GLib::Bytes) —

    A new #GBytes structure containing the copied data.

#distance_from_discont ⇒ Integer

Get the distance in bytes since the last buffer with the
%GST_BUFFER_FLAG_DISCONT flag.

The distance will be reset to 0 for all buffers with
%GST_BUFFER_FLAG_DISCONT on them, and then calculated for all other
following buffers based on their size.

Returns:

  • (Integer) —

    The offset. Can be %GST_BUFFER_OFFSET_NONE.

#dts_at_discont ⇒ Gst::ClockTime

Get the DTS that was on the last buffer with the GST_BUFFER_FLAG_DISCONT
flag, or GST_CLOCK_TIME_NONE.

Returns:

  • (Gst::ClockTime) —

    The DTS at the last discont or GST_CLOCK_TIME_NONE.

#flush(flush) ⇒ nil

Flushes the first flush bytes in the adapter. The caller must ensure that
at least this many bytes are available.

See also: gst_adapter_map(), gst_adapter_unmap()

Parameters:

  • flush (Integer) —

    the number of bytes to flush

Returns:

  • (nil)

#get_buffer(nbytes) ⇒ Gst::Buffer

Returns a Gst::Buffer containing the first nbytes of the adapter, but
does not flush them from the adapter. See gst_adapter_take_buffer()
for details.

Caller owns a reference to the returned buffer. gst_buffer_unref() after
usage.

Free-function: gst_buffer_unref

Parameters:

  • nbytes (Integer) —

    the number of bytes to get

Returns:

  • (Gst::Buffer) —

    a Gst::Buffer containing the first
    nbytes of the adapter, or nil if nbytes bytes are not available.
    gst_buffer_unref() when no longer needed.

#get_buffer_fast(nbytes) ⇒ Gst::Buffer

Returns a Gst::Buffer containing the first nbytes of the adapter, but
does not flush them from the adapter. See gst_adapter_take_buffer_fast()
for details.

Caller owns a reference to the returned buffer. gst_buffer_unref() after
usage.

Free-function: gst_buffer_unref

Parameters:

  • nbytes (Integer) —

    the number of bytes to get

Returns:

  • (Gst::Buffer) —

    a Gst::Buffer containing the first
    nbytes of the adapter, or nil if nbytes bytes are not available.
    gst_buffer_unref() when no longer needed.

#get_buffer_list(nbytes) ⇒ Gst::BufferList

Returns a Gst::BufferList of buffers containing the first nbytes bytes of
the adapter but does not flush them from the adapter. See
gst_adapter_take_buffer_list() for details.

Caller owns the returned list. Call gst_buffer_list_unref() to free
the list after usage.

Parameters:

  • nbytes (Integer) —

    the number of bytes to get

Returns:

  • (Gst::BufferList) —

    a Gst::BufferList of buffers containing
    the first nbytes of the adapter, or nil if nbytes bytes are not
    available

#get_list(nbytes) ⇒ GLib::List<Gst::Buffer>

Returns a #GList of buffers containing the first nbytes bytes of the
adapter, but does not flush them from the adapter. See
gst_adapter_take_list() for details.

Caller owns returned list and contained buffers. gst_buffer_unref() each
buffer in the list before freeing the list after usage.

Parameters:

  • nbytes (Integer) —

    the number of bytes to get

Returns:

  • (GLib::List<Gst::Buffer>) —

    a #GList of
    buffers containing the first nbytes of the adapter, or nil if nbytes
    bytes are not available

#map(size) ⇒ Array<Integer>

Gets the first size bytes stored in the adapter. The returned pointer is
valid until the next function is called on the adapter.

Note that setting the returned pointer as the data of a Gst::Buffer is
incorrect for general-purpose plugins. The reason is that if a downstream
element stores the buffer so that it has access to it outside of the bounds
of its chain function, the buffer will have an invalid data pointer after
your element flushes the bytes. In that case you should use
gst_adapter_take(), which returns a freshly-allocated buffer that you can set
as Gst::Buffer memory or the potentially more performant
gst_adapter_take_buffer().

Returns nil if size bytes are not available.

Parameters:

  • size (Integer) —

    the number of bytes to map/peek

Returns:

  • (Array<Integer>) —

    a pointer to the first size bytes of data, or nil

#masked_scan_uint32(mask, pattern, offset, size) ⇒ GstBase::gssize

Scan for pattern pattern with applied mask mask in the adapter data,
starting from offset offset.

The bytes in pattern and mask are interpreted left-to-right, regardless
of endianness. All four bytes of the pattern must be present in the
adapter for it to match, even if the first or last bytes are masked out.

It is an error to call this function without making sure that there is
enough data (offset+size bytes) in the adapter.

This function calls gst_adapter_masked_scan_uint32_peek() passing nil
for value.
Example:
|[
// Assume the adapter contains 0x00 0x01 0x02 ... 0xfe 0xff

gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x00010203, 0, 256);
// -> returns 0
gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x00010203, 1, 255);
// -> returns -1
gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x01020304, 1, 255);
// -> returns 1
gst_adapter_masked_scan_uint32 (adapter, 0xffff, 0x0001, 0, 256);
// -> returns -1
gst_adapter_masked_scan_uint32 (adapter, 0xffff, 0x0203, 0, 256);
// -> returns 0
gst_adapter_masked_scan_uint32 (adapter, 0xffff0000, 0x02030000, 0, 256);
// -> returns 2
gst_adapter_masked_scan_uint32 (adapter, 0xffff0000, 0x02030000, 0, 4);
// -> returns -1
]|

Parameters:

  • mask (Integer) —

    mask to apply to data before matching against pattern

  • pattern (Integer) —

    pattern to match (after mask is applied)

  • offset (Integer) —

    offset into the adapter data from which to start scanning, returns
    the last scanned position.

  • size (Integer) —

    number of bytes to scan from offset

Returns:

  • (GstBase::gssize) —

    offset of the first match, or -1 if no match was found.

#masked_scan_uint32_peek(mask, pattern, offset, size, value) ⇒ GstBase::gssize

Scan for pattern pattern with applied mask mask in the adapter data,
starting from offset offset. If a match is found, the value that matched
is returned through value, otherwise value is left untouched.

The bytes in pattern and mask are interpreted left-to-right, regardless
of endianness. All four bytes of the pattern must be present in the
adapter for it to match, even if the first or last bytes are masked out.

It is an error to call this function without making sure that there is
enough data (offset+size bytes) in the adapter.

Parameters:

  • mask (Integer) —

    mask to apply to data before matching against pattern

  • pattern (Integer) —

    pattern to match (after mask is applied)

  • offset (Integer) —

    offset into the adapter data from which to start scanning, returns
    the last scanned position.

  • size (Integer) —

    number of bytes to scan from offset

  • value (Integer) —

    pointer to uint32 to return matching data

Returns:

  • (GstBase::gssize) —

    offset of the first match, or -1 if no match was found.

#offset_at_discont ⇒ Integer

Get the offset that was on the last buffer with the GST_BUFFER_FLAG_DISCONT
flag, or GST_BUFFER_OFFSET_NONE.

Returns:

  • (Integer) —

    The offset at the last discont or GST_BUFFER_OFFSET_NONE.

#prev_dts(distance) ⇒ Gst::ClockTime

Get the dts that was before the current byte in the adapter. When
distance is given, the amount of bytes between the dts and the current
position is returned.

The dts is reset to GST_CLOCK_TIME_NONE and the distance is set to 0 when
the adapter is first created or when it is cleared. This also means that before
the first byte with a dts is removed from the adapter, the dts
and distance returned are GST_CLOCK_TIME_NONE and 0 respectively.

Parameters:

  • distance (Integer) —

    pointer to location for distance, or nil

Returns:

  • (Gst::ClockTime) —

    The previously seen dts.

#prev_dts_at_offset(offset, distance) ⇒ Gst::ClockTime

Get the dts that was before the byte at offset offset in the adapter. When
distance is given, the amount of bytes between the dts and the current
position is returned.

The dts is reset to GST_CLOCK_TIME_NONE and the distance is set to 0 when
the adapter is first created or when it is cleared. This also means that before
the first byte with a dts is removed from the adapter, the dts
and distance returned are GST_CLOCK_TIME_NONE and 0 respectively.

Parameters:

  • offset (Integer) —

    the offset in the adapter at which to get timestamp

  • distance (Integer) —

    pointer to location for distance, or nil

Returns:

  • (Gst::ClockTime) —

    The previously seen dts at given offset.

#prev_offset(distance) ⇒ Integer

Get the offset that was before the current byte in the adapter. When
distance is given, the amount of bytes between the offset and the current
position is returned.

The offset is reset to GST_BUFFER_OFFSET_NONE and the distance is set to 0
when the adapter is first created or when it is cleared. This also means that
before the first byte with an offset is removed from the adapter, the offset
and distance returned are GST_BUFFER_OFFSET_NONE and 0 respectively.

Parameters:

  • distance (Integer) —

    pointer to a location for distance, or nil

Returns:

  • (Integer) —

    The previous seen offset.

#prev_pts(distance) ⇒ Gst::ClockTime

Get the pts that was before the current byte in the adapter. When
distance is given, the amount of bytes between the pts and the current
position is returned.

The pts is reset to GST_CLOCK_TIME_NONE and the distance is set to 0 when
the adapter is first created or when it is cleared. This also means that before
the first byte with a pts is removed from the adapter, the pts
and distance returned are GST_CLOCK_TIME_NONE and 0 respectively.

Parameters:

  • distance (Integer) —

    pointer to location for distance, or nil

Returns:

  • (Gst::ClockTime) —

    The previously seen pts.

#prev_pts_at_offset(offset, distance) ⇒ Gst::ClockTime

Get the pts that was before the byte at offset offset in the adapter. When
distance is given, the amount of bytes between the pts and the current
position is returned.

The pts is reset to GST_CLOCK_TIME_NONE and the distance is set to 0 when
the adapter is first created or when it is cleared. This also means that before
the first byte with a pts is removed from the adapter, the pts
and distance returned are GST_CLOCK_TIME_NONE and 0 respectively.

Parameters:

  • offset (Integer) —

    the offset in the adapter at which to get timestamp

  • distance (Integer) —

    pointer to location for distance, or nil

Returns:

  • (Gst::ClockTime) —

    The previously seen pts at given offset.

#pts_at_discont ⇒ Gst::ClockTime

Get the PTS that was on the last buffer with the GST_BUFFER_FLAG_DISCONT
flag, or GST_CLOCK_TIME_NONE.

Returns:

  • (Gst::ClockTime) —

    The PTS at the last discont or GST_CLOCK_TIME_NONE.

#push(buf) ⇒ nil

Adds the data from buf to the data stored inside adapter and takes
ownership of the buffer.

Parameters:

  • buf (Gst::Buffer) —

    a Gst::Buffer to add to queue in the adapter

Returns:

  • (nil)

#take(nbytes) ⇒ Array<Integer>

Returns a freshly allocated buffer containing the first nbytes bytes of the
adapter. The returned bytes will be flushed from the adapter.

Caller owns returned value. g_free after usage.

Free-function: g_free

Parameters:

  • nbytes (Integer) —

    the number of bytes to take

Returns:

  • (Array<Integer>) —

    oven-fresh hot data, or nil if nbytes bytes are not available

#take_buffer(nbytes) ⇒ Gst::Buffer

Returns a Gst::Buffer containing the first nbytes bytes of the
adapter. The returned bytes will be flushed from the adapter.
This function is potentially more performant than
gst_adapter_take() since it can reuse the memory in pushed buffers
by subbuffering or merging. This function will always return a
buffer with a single memory region.

Note that no assumptions should be made as to whether certain buffer
flags such as the DISCONT flag are set on the returned buffer, or not.
The caller needs to explicitly set or unset flags that should be set or
unset.

Since 1.6 this will also copy over all GstMeta of the input buffers except
for meta with the %GST_META_FLAG_POOLED flag or with the "memory" tag.

Caller owns a reference to the returned buffer. gst_buffer_unref() after
usage.

Free-function: gst_buffer_unref

Parameters:

  • nbytes (Integer) —

    the number of bytes to take

Returns:

  • (Gst::Buffer) —

    a Gst::Buffer containing the first
    nbytes of the adapter, or nil if nbytes bytes are not available.
    gst_buffer_unref() when no longer needed.

#take_buffer_fast(nbytes) ⇒ Gst::Buffer

Returns a Gst::Buffer containing the first nbytes of the adapter.
The returned bytes will be flushed from the adapter. This function
is potentially more performant than gst_adapter_take_buffer() since
it can reuse the memory in pushed buffers by subbuffering or
merging. Unlike gst_adapter_take_buffer(), the returned buffer may
be composed of multiple non-contiguous Gst::Memory objects, no
copies are made.

Note that no assumptions should be made as to whether certain buffer
flags such as the DISCONT flag are set on the returned buffer, or not.
The caller needs to explicitly set or unset flags that should be set or
unset.

This will also copy over all GstMeta of the input buffers except
for meta with the %GST_META_FLAG_POOLED flag or with the "memory" tag.

This function can return buffer up to the return value of
gst_adapter_available() without making copies if possible.

Caller owns a reference to the returned buffer. gst_buffer_unref() after
usage.

Free-function: gst_buffer_unref

Parameters:

  • nbytes (Integer) —

    the number of bytes to take

Returns:

  • (Gst::Buffer) —

    a Gst::Buffer containing the first
    nbytes of the adapter, or nil if nbytes bytes are not available.
    gst_buffer_unref() when no longer needed.

#take_buffer_list(nbytes) ⇒ Gst::BufferList

Returns a Gst::BufferList of buffers containing the first nbytes bytes of
the adapter. The returned bytes will be flushed from the adapter.
When the caller can deal with individual buffers, this function is more
performant because no memory should be copied.

Caller owns the returned list. Call gst_buffer_list_unref() to free
the list after usage.

Parameters:

  • nbytes (Integer) —

    the number of bytes to take

Returns:

  • (Gst::BufferList) —

    a Gst::BufferList of buffers containing
    the first nbytes of the adapter, or nil if nbytes bytes are not
    available

#take_list(nbytes) ⇒ GLib::List<Gst::Buffer>

Returns a #GList of buffers containing the first nbytes bytes of the
adapter. The returned bytes will be flushed from the adapter.
When the caller can deal with individual buffers, this function is more
performant because no memory should be copied.

Caller owns returned list and contained buffers. gst_buffer_unref() each
buffer in the list before freeing the list after usage.

Parameters:

  • nbytes (Integer) —

    the number of bytes to take

Returns:

  • (GLib::List<Gst::Buffer>) —

    a #GList of
    buffers containing the first nbytes of the adapter, or nil if nbytes
    bytes are not available

#unmap ⇒ nil

Releases the memory obtained with the last gst_adapter_map().

Returns:

  • (nil)