Public interface

Data Structures
struct	hvd_config
	Decoder configuration. More...
struct	hvd_packet
	Encoded data packet. More...
struct	hvd
	Internal library data passed around by the user. More...

Enumerations
enum	hvd_retval_enum { HVD_AGAIN =AVERROR(EAGAIN), HVD_ERROR =-1, HVD_OK =0 }
	Constants returned by most of library functions. More...

Functions
struct hvd *	hvd_init (const struct hvd_config *config)
	Initialize internal library data. More...
void	hvd_close (struct hvd *h)
	Free library resources. More...
int	hvd_send_packet (struct hvd *h, struct hvd_packet *packet)
	Send packet to hardware for decoding. More...
AVFrame *	hvd_receive_frame (struct hvd *h, int *error)
	Retrieve decoded frame data from hardware. More...

Detailed Description

Enumeration Type Documentation

enum hvd_retval_enum

Constants returned by most of library functions.

Enumerator
HVD_AGAIN	hvd_send_packet was not accepted (e.g. buffers full), use hvd_receive_frame before next call
HVD_ERROR	error occured
HVD_OK	succesfull execution

Function Documentation

void hvd_close

(

struct hvd *

h

)

Free library resources.

Cleans and frees library memory.

Parameters

h	pointer to internal library data

See also

hvd_init

struct hvd* hvd_init

(

const struct hvd_config *

config

)

Initialize internal library data.

Parameters

config

decoder configuration

Returns

• pointer to internal library data
• NULL on error, errors printed to stderr

See also

hvd_config, hvd_close

AVFrame* hvd_receive_frame	(	struct hvd *	h,
		int *	error
	)

Retrieve decoded frame data from hardware.

Keep calling this functions after hvd_send_packet until NULL is returned. The ownership of returned FFmpeg AVFrame remains with the library:

• consume it immidiately
• or copy the data

Parameters

h	pointer to internal library data
error	pointer to error code

Returns

• AVFrame* pointer to FFMpeg AVFrame, you are mainly interested in data and linesize arrays
• NULL when no more data is pending, query error argument to check result (HVD_OK on success)

See also

hvd_send_packet

Example (in decoding loop):

//send data for hardware decoding
if(hvd_send_packet(h, packet) != HVD_OK)
  break; //break on error

//get the decoded data
while( (frame = hvd_receive_frame(av, &error) ) )
{
  //do something with frame->data, frame->linesize
}

//NULL frame and non-zero failed indicates failure during decoding
if(failed)
  break; //break on error

int hvd_send_packet	(	struct hvd *	h,
		struct hvd_packet *	packet
	)

Send packet to hardware for decoding.

Pass data in hvd_packet for decoding. Follow with hvd_receive_frame to get decoded data from hardware.

If you have simple loop like:

• send encoded data with hve_send_packet
• receive decoded data with hve_receive_frame

HVD_AGAIN return value will never happen. If you are sending lots of data and not reading you may get HVD_AGAIN when buffers are full.

When you are done with decoding call with:

• NULL packet argument
• or packet with NULL data and 0 size to flush the decoder and follow with hvd_receive_frame as usual to get last frames from decoder.

After flushing and reading last frames you can follow with decoding new stream.

Perfomance hints:

• don't copy data from your source, pass the pointer in packet->data

Parameters

h	pointer to internal library data
packet	data to decode

Returns

• HVD_OK on success
• HVD_ERROR on error
• HVD_AGAIN input was rejected, read data with hvd_receive_packet before next try

See also

hvd_packet, hvd_receive_frame

Example flushing:

//flush
hvd_send_packet(hardware_decoder, NULL);

//retrieve last frames from decoder as usual
while( (frame=hvd_receive_frame(hardware_decoder, &failed)) )
{
   //do something with frame->data, frame->linesize
}

//NULL frame and non-zero failed indicates failure during decoding
if(failed)
   //your logic on failure

//terminate or continue decoding new stream