FFmpeg
hw_decode.c

This example shows how to do HW-accelerated decoding with output frames from the HW video surfaces.

/*
* Copyright (c) 2017 Jun Zhao
* Copyright (c) 2017 Kaixuan Liu
*
* HW Acceleration API (video decoding) decode sample
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
/**
* @file
* HW-Accelerated decoding example.
*
* @example hw_decode.c
* This example shows how to do HW-accelerated decoding with output
* frames from the HW video surfaces.
*/
#include <stdio.h>
#include <libavutil/opt.h>
static FILE *output_file = NULL;
{
int err = 0;
NULL, NULL, 0)) < 0) {
fprintf(stderr, "Failed to create specified HW device.\n");
return err;
}
ctx->hw_device_ctx = av_buffer_ref(hw_device_ctx);
return err;
}
const enum AVPixelFormat *pix_fmts)
{
const enum AVPixelFormat *p;
for (p = pix_fmts; *p != -1; p++) {
if (*p == hw_pix_fmt)
return *p;
}
fprintf(stderr, "Failed to get HW surface format.\n");
}
static int decode_write(AVCodecContext *avctx, AVPacket *packet)
{
AVFrame *frame = NULL, *sw_frame = NULL;
AVFrame *tmp_frame = NULL;
uint8_t *buffer = NULL;
int size;
int ret = 0;
ret = avcodec_send_packet(avctx, packet);
if (ret < 0) {
fprintf(stderr, "Error during decoding\n");
return ret;
}
while (1) {
if (!(frame = av_frame_alloc()) || !(sw_frame = av_frame_alloc())) {
fprintf(stderr, "Can not alloc frame\n");
ret = AVERROR(ENOMEM);
goto fail;
}
if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
av_frame_free(&sw_frame);
return 0;
} else if (ret < 0) {
fprintf(stderr, "Error while decoding\n");
goto fail;
}
if (frame->format == hw_pix_fmt) {
/* retrieve data from GPU to CPU */
if ((ret = av_hwframe_transfer_data(sw_frame, frame, 0)) < 0) {
fprintf(stderr, "Error transferring the data to system memory\n");
goto fail;
}
tmp_frame = sw_frame;
} else
tmp_frame = frame;
size = av_image_get_buffer_size(tmp_frame->format, tmp_frame->width,
tmp_frame->height, 1);
if (!buffer) {
fprintf(stderr, "Can not alloc buffer\n");
ret = AVERROR(ENOMEM);
goto fail;
}
(const uint8_t * const *)tmp_frame->data,
(const int *)tmp_frame->linesize, tmp_frame->format,
tmp_frame->width, tmp_frame->height, 1);
if (ret < 0) {
fprintf(stderr, "Can not copy image to buffer\n");
goto fail;
}
if ((ret = fwrite(buffer, 1, size, output_file)) < 0) {
fprintf(stderr, "Failed to dump raw data.\n");
goto fail;
}
av_frame_free(&sw_frame);
if (ret < 0)
return ret;
}
}
int main(int argc, char *argv[])
{
AVFormatContext *input_ctx = NULL;
const AVCodec *decoder = NULL;
AVPacket packet;
int i;
if (argc < 4) {
fprintf(stderr, "Usage: %s <device type> <input file> <output file>\n", argv[0]);
return -1;
}
fprintf(stderr, "Device type %s is not supported.\n", argv[1]);
fprintf(stderr, "Available device types:");
fprintf(stderr, " %s", av_hwdevice_get_type_name(type));
fprintf(stderr, "\n");
return -1;
}
/* open the input file */
if (avformat_open_input(&input_ctx, argv[2], NULL, NULL) != 0) {
fprintf(stderr, "Cannot open input file '%s'\n", argv[2]);
return -1;
}
if (avformat_find_stream_info(input_ctx, NULL) < 0) {
fprintf(stderr, "Cannot find input stream information.\n");
return -1;
}
/* find the video stream information */
ret = av_find_best_stream(input_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, &decoder, 0);
if (ret < 0) {
fprintf(stderr, "Cannot find a video stream in the input file\n");
return -1;
}
for (i = 0;; i++) {
if (!config) {
fprintf(stderr, "Decoder %s does not support device type %s.\n",
return -1;
}
config->device_type == type) {
hw_pix_fmt = config->pix_fmt;
break;
}
}
return AVERROR(ENOMEM);
video = input_ctx->streams[video_stream];
return -1;
return -1;
fprintf(stderr, "Failed to open codec for stream #%u\n", video_stream);
return -1;
}
/* open the file to dump raw data */
output_file = fopen(argv[3], "w+b");
/* actual decoding and dump the raw data */
while (ret >= 0) {
if ((ret = av_read_frame(input_ctx, &packet)) < 0)
break;
if (video_stream == packet.stream_index)
av_packet_unref(&packet);
}
/* flush the decoder */
packet.data = NULL;
packet.size = 0;
av_packet_unref(&packet);
fclose(output_file);
avformat_close_input(&input_ctx);
return 0;
}
av_packet_unref
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:417
AVCodec
AVCodec.
Definition: codec.h:197
hw_pix_fmt
static enum AVPixelFormat hw_pix_fmt
Definition: hw_decode.c:46
AVPixelFormat
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
opt.h
AVCodecContext::get_format
enum AVPixelFormat(* get_format)(struct AVCodecContext *s, const enum AVPixelFormat *fmt)
Callback to negotiate the pixel format.
Definition: avcodec.h:643
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:57
av_frame_free
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:112
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:303
pixdesc.h
AVFormatContext::streams
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1175
AVFrame::width
int width
Definition: frame.h:361
AV_HWDEVICE_TYPE_NONE
@ AV_HWDEVICE_TYPE_NONE
Definition: hwcontext.h:28
AVPacket::data
uint8_t * data
Definition: packet.h:373
av_hwdevice_find_type_by_name
enum AVHWDeviceType av_hwdevice_find_type_by_name(const char *name)
Look up an AVHWDeviceType by name.
Definition: hwcontext.c:82
av_hwdevice_iterate_types
enum AVHWDeviceType av_hwdevice_iterate_types(enum AVHWDeviceType prev)
Iterate over supported device types.
Definition: hwcontext.c:101
av_read_frame
int av_read_frame(AVFormatContext *s, AVPacket *pkt)
Return the next frame of a stream.
Definition: utils.c:1669
tf_sess_config.config
config
Definition: tf_sess_config.py:33
AVFrame::data
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:317
av_malloc
#define av_malloc(s)
Definition: tableprint_vlc.h:31
av_find_best_stream
int av_find_best_stream(AVFormatContext *ic, enum AVMediaType type, int wanted_stream_nb, int related_stream, const AVCodec **decoder_ret, int flags)
Find the "best" stream in the file.
Definition: utils.c:4121
avformat_close_input
void avformat_close_input(AVFormatContext **s)
Close an opened input AVFormatContext.
Definition: utils.c:4347
decoder
static const chunk_decoder decoder[8]
Definition: dfa.c:330
get_hw_format
static enum AVPixelFormat get_hw_format(AVCodecContext *ctx, const enum AVPixelFormat *pix_fmts)
Definition: hw_decode.c:63
fail
#define fail()
Definition: checkasm.h:136
type
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf type
Definition: writing_filters.txt:86
av_frame_alloc
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
Definition: frame.c:99
avassert.h
avformat_open_input
int avformat_open_input(AVFormatContext **ps, const char *url, const AVInputFormat *fmt, AVDictionary **options)
Open an input stream and read the header.
Definition: utils.c:483
avcodec_alloc_context3
AVCodecContext * avcodec_alloc_context3(const AVCodec *codec)
Allocate an AVCodecContext and set its fields to default values.
Definition: options.c:141
avcodec_receive_frame
int avcodec_receive_frame(AVCodecContext *avctx, AVFrame *frame)
Return decoded output data from a decoder.
Definition: decode.c:639
AVHWDeviceType
AVHWDeviceType
Definition: hwcontext.h:27
pix_fmts
static enum AVPixelFormat pix_fmts[]
Definition: libkvazaar.c:290
decoder_ctx
static AVCodecContext * decoder_ctx
Definition: vaapi_transcode.c:43
ctx
AVFormatContext * ctx
Definition: movenc.c:48
av_hwdevice_get_type_name
const char * av_hwdevice_get_type_name(enum AVHWDeviceType type)
Get the string name of an AVHWDeviceType.
Definition: hwcontext.c:92
AVFormatContext
Format I/O context.
Definition: avformat.h:1107
NULL
#define NULL
Definition: coverity.c:32
av_buffer_unref
void av_buffer_unref(AVBufferRef **buf)
Free a given reference and automatically free the buffer if there are no more references to it.
Definition: buffer.c:125
avcodec_free_context
void avcodec_free_context(AVCodecContext **avctx)
Free the codec context and everything associated with it and write NULL to the provided pointer.
Definition: options.c:156
AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX
@ AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX
The codec supports this format via the hw_device_ctx interface.
Definition: codec.h:422
avcodec_open2
int attribute_align_arg avcodec_open2(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **options)
Initialize the AVCodecContext to use the given AVCodec.
Definition: avcodec.c:137
avformat_find_stream_info
int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
Read packets of a media file to get stream information.
Definition: utils.c:3547
AVPacket::size
int size
Definition: packet.h:374
size
int size
Definition: twinvq_data.h:10344
AVFrame::format
int format
format of the frame, -1 if unknown or unset Values correspond to enum AVPixelFormat for video frames,...
Definition: frame.h:376
av_image_get_buffer_size
int av_image_get_buffer_size(enum AVPixelFormat pix_fmt, int width, int height, int align)
Return the size in bytes of the amount of data required to store an image with the given parameters.
Definition: imgutils.c:466
avcodec_send_packet
int avcodec_send_packet(AVCodecContext *avctx, const AVPacket *avpkt)
Supply raw packet data as input to a decoder.
Definition: decode.c:576
i
int i
Definition: input.c:406
hw_device_ctx
static AVBufferRef * hw_device_ctx
Definition: hw_decode.c:45
avcodec_parameters_to_context
int avcodec_parameters_to_context(AVCodecContext *codec, const AVCodecParameters *par)
Fill the codec context based on the values from the supplied codec parameters.
Definition: codec_par.c:147
main
int main(int argc, char *argv[])
Definition: hw_decode.c:149
avcodec.h
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:847
frame
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a frame
Definition: filter_design.txt:264
video_stream
static AVStream * video_stream
Definition: demuxing_decoding.c:42
av_hwdevice_ctx_create
int av_hwdevice_ctx_create(AVBufferRef **pdevice_ref, enum AVHWDeviceType type, const char *device, AVDictionary *opts, int flags)
Open a device of the specified type and create an AVHWDeviceContext for it.
Definition: hwcontext.c:610
avformat.h
av_hwframe_transfer_data
int av_hwframe_transfer_data(AVFrame *dst, const AVFrame *src, int flags)
Copy data to or from a hw surface.
Definition: hwcontext.c:443
output_file
static FILE * output_file
Definition: hw_decode.c:47
AVCodecContext
main external API structure.
Definition: avcodec.h:379
AVFrame::height
int height
Definition: frame.h:361
hw_decoder_init
static int hw_decoder_init(AVCodecContext *ctx, const enum AVHWDeviceType type)
Definition: hw_decode.c:49
buffer
the frame and frame reference mechanism is intended to as much as expensive copies of that data while still allowing the filters to produce correct results The data is stored in buffers represented by AVFrame structures Several references can point to the same frame buffer
Definition: filter_design.txt:49
AV_PIX_FMT_NONE
@ AV_PIX_FMT_NONE
Definition: pixfmt.h:65
video
A Quick Description Of Rate Distortion Theory We want to encode a video
Definition: rate_distortion.txt:3
AVPacket::stream_index
int stream_index
Definition: packet.h:375
av_buffer_ref
AVBufferRef * av_buffer_ref(AVBufferRef *buf)
Create a new reference to an AVBuffer.
Definition: buffer.c:93
avcodec_get_hw_config
const AVCodecHWConfig * avcodec_get_hw_config(const AVCodec *codec, int index)
Retrieve supported hardware configurations for a codec.
Definition: utils.c:858
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
AVBufferRef
A reference to a data buffer.
Definition: buffer.h:82
av_image_copy_to_buffer
int av_image_copy_to_buffer(uint8_t *dst, int dst_size, const uint8_t *const src_data[4], const int src_linesize[4], enum AVPixelFormat pix_fmt, int width, int height, int align)
Copy image data from an image into a buffer.
Definition: imgutils.c:501
AVPacket
This structure stores compressed data.
Definition: packet.h:350
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:35
imgutils.h
hwcontext.h
AVFrame::linesize
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:334
AVCodecHWConfig
Definition: codec.h:454
decode_write
static int decode_write(AVCodecContext *avctx, AVPacket *packet)
Definition: hw_decode.c:77