Media Tool
Media tool enables your application to manage various media handles.
The main features of the Media Tool API include:
-
Creating the media_format handle to specify video or audio information.
You can set and get video or audio information using the media_format handle.
-
Creating the media_packet handle to include metadata (such as pts, dts, and duration) and allocate a buffer to the heap or TBM surface.
You can set and get the metadata using the media_packet handle.
The media_format_h handle is created by the caller, who can set and get the video or audio information. The media_format handle creates the media_packet_h handle and allocates the buffer. The caller can set and get the metadata with the media_packet_h handle.
The following table describes the reference count design of the media_format_h handle.
| Function | Reference count number | Description |
|---|---|---|
|
media_format_h fmt1, fmt2, tmp; media_packet_h pkt1, pkt2; media_format_create(&fmt1); |
fmt1: 1 | Define the media_format_h and media_packet_h handles.
Create the fmt1 handle. |
| media_packet_create(&pkt1, fmt1); | fmt1: 2 | After the media_packet_create() function, you must use the media_format_unref() function. |
| media_format_unref(fmt1); | fmt1: 1 | If the ref_count is 1, the fmt1 is currently owned by the pkt1 only. |
| media_packet_copy(pkt1, &pkt2); | fmt1: 2 | Copy the pkt1 metadata to pkt2, except the allocated buffer and buffer size. pkt2 refers to fmt1, and fmt1 ref_count is increased. |
| media_packet_get_format(pkt1, &tmp); | fmt1: 3 | If you try to call the set_video_info function for fmt1 (tmp), ref_count is bigger than 1, and fmt1 cannot be modified. To modify fmt1 data, call the media_format_make_writable() function. |
| media_format_set_video_info(tmp, ...); | fmt1: 3 | Define the media_format_h and media_packet_h handles.
Create the fmt1 handle. |
| media_format_make_writable(tmp, &fmt2); |
fmt1: 2 fmt2: 1 |
If called, the tmp (fmt1) ref_count is decreased. Creates the fmt2 handle and copies the fmt1 data to fmt2. |
| media_format_set_video_info(fmt2, ...); |
fmt1: 2 fmt2: 1 |
fmt2 ref_count is 1, which means that you can modify the fmt2 data. |
| media_packet_set_format(pkt2, fmt2); |
fmt1: 2
fmt2: 2 |
Set the modified fmt2 to the pkt2 handle. You must call the media_format_unref(fmt2) function. |
| media_format_unref(tmp); |
fmt1: 1
fmt2: 2 |
You must call this function because of the media_packet_get_format(pkt1, &tmp) function call. |
| media_format_unref(fmt2); |
fmt1: 1 fmt2: 1 |
You must call this function because of the media_packet_set_video(fmt2..) function call. |
| media_packet_destroy(pkt1); |
fmt1: 1 > finalize fmt2: 1 |
If you destroy the pkt1 handle, the fmt1 ref_count is decreased. If the ref_count becomes 0, fmt1 is freed. |
| media_packet_destroy(pkt2); |
fmt1: 1 > finalize fmt2: 0 > finalize |
If you destroy the pkt2 handle, the fmt2 ref_count is decreased. If the ref_count becomes 0, fmt2 is freed. |
