2 * Copyright (c) 2017 Jun Zhao
3 * Copyright (c) 2017 Kaixuan Liu
5 * HW Acceleration API (video decoding) decode sample
7 * This file is part of FFmpeg.
9 * FFmpeg is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
14 * FFmpeg is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with FFmpeg; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
26 * HW-Accelerated decoding example.
28 * @example hw_decode.c
29 * This example shows how to do HW-accelerated decoding with output
30 * frames from the HW video surfaces.
35 #include <libavcodec/avcodec.h>
36 #include <libavformat/avformat.h>
37 #include <libavutil/pixdesc.h>
38 #include <libavutil/hwcontext.h>
39 #include <libavutil/opt.h>
40 #include <libavutil/avassert.h>
41 #include <libavutil/imgutils.h>
43 static AVBufferRef *hw_device_ctx = NULL;
44 static enum AVPixelFormat hw_pix_fmt;
45 static FILE *output_file = NULL;
47 static int hw_decoder_init(AVCodecContext *ctx, const enum AVHWDeviceType type)
51 if ((err = av_hwdevice_ctx_create(&hw_device_ctx, type,
52 NULL, NULL, 0)) < 0) {
53 fprintf(stderr, "Failed to create specified HW device.\n");
56 ctx->hw_device_ctx = av_buffer_ref(hw_device_ctx);
61 static enum AVPixelFormat get_hw_format(AVCodecContext *ctx,
62 const enum AVPixelFormat *pix_fmts)
64 const enum AVPixelFormat *p;
66 for (p = pix_fmts; *p != -1; p++) {
71 fprintf(stderr, "Failed to get HW surface format.\n");
72 return AV_PIX_FMT_NONE;
75 static int decode_write(AVCodecContext *avctx, AVPacket *packet)
77 AVFrame *frame = NULL, *sw_frame = NULL;
78 AVFrame *tmp_frame = NULL;
79 uint8_t *buffer = NULL;
83 ret = avcodec_send_packet(avctx, packet);
85 fprintf(stderr, "Error during decoding\n");
90 if (!(frame = av_frame_alloc()) || !(sw_frame = av_frame_alloc())) {
91 fprintf(stderr, "Can not alloc frame\n");
92 ret = AVERROR(ENOMEM);
96 ret = avcodec_receive_frame(avctx, frame);
97 if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
98 av_frame_free(&frame);
99 av_frame_free(&sw_frame);
101 } else if (ret < 0) {
102 fprintf(stderr, "Error while decoding\n");
106 if (frame->format == hw_pix_fmt) {
107 /* retrieve data from GPU to CPU */
108 if ((ret = av_hwframe_transfer_data(sw_frame, frame, 0)) < 0) {
109 fprintf(stderr, "Error transferring the data to system memory\n");
112 tmp_frame = sw_frame;
116 size = av_image_get_buffer_size(tmp_frame->format, tmp_frame->width,
117 tmp_frame->height, 1);
118 buffer = av_malloc(size);
120 fprintf(stderr, "Can not alloc buffer\n");
121 ret = AVERROR(ENOMEM);
124 ret = av_image_copy_to_buffer(buffer, size,
125 (const uint8_t * const *)tmp_frame->data,
126 (const int *)tmp_frame->linesize, tmp_frame->format,
127 tmp_frame->width, tmp_frame->height, 1);
129 fprintf(stderr, "Can not copy image to buffer\n");
133 if ((ret = fwrite(buffer, 1, size, output_file)) < 0) {
134 fprintf(stderr, "Failed to dump raw data.\n");
139 av_frame_free(&frame);
140 av_frame_free(&sw_frame);
147 int main(int argc, char *argv[])
149 AVFormatContext *input_ctx = NULL;
150 int video_stream, ret;
151 AVStream *video = NULL;
152 AVCodecContext *decoder_ctx = NULL;
153 AVCodec *decoder = NULL;
155 enum AVHWDeviceType type;
159 fprintf(stderr, "Usage: %s <device type> <input file> <output file>\n", argv[0]);
163 type = av_hwdevice_find_type_by_name(argv[1]);
164 if (type == AV_HWDEVICE_TYPE_NONE) {
165 fprintf(stderr, "Device type %s is not supported.\n", argv[1]);
166 fprintf(stderr, "Available device types:");
167 while((type = av_hwdevice_iterate_types(type)) != AV_HWDEVICE_TYPE_NONE)
168 fprintf(stderr, " %s", av_hwdevice_get_type_name(type));
169 fprintf(stderr, "\n");
173 /* open the input file */
174 if (avformat_open_input(&input_ctx, argv[2], NULL, NULL) != 0) {
175 fprintf(stderr, "Cannot open input file '%s'\n", argv[2]);
179 if (avformat_find_stream_info(input_ctx, NULL) < 0) {
180 fprintf(stderr, "Cannot find input stream information.\n");
184 /* find the video stream information */
185 ret = av_find_best_stream(input_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, &decoder, 0);
187 fprintf(stderr, "Cannot find a video stream in the input file\n");
193 const AVCodecHWConfig *config = avcodec_get_hw_config(decoder, i);
195 fprintf(stderr, "Decoder %s does not support device type %s.\n",
196 decoder->name, av_hwdevice_get_type_name(type));
199 if (config->methods & AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX &&
200 config->device_type == type) {
201 hw_pix_fmt = config->pix_fmt;
206 if (!(decoder_ctx = avcodec_alloc_context3(decoder)))
207 return AVERROR(ENOMEM);
209 video = input_ctx->streams[video_stream];
210 if (avcodec_parameters_to_context(decoder_ctx, video->codecpar) < 0)
213 decoder_ctx->get_format = get_hw_format;
214 av_opt_set_int(decoder_ctx, "refcounted_frames", 1, 0);
216 if (hw_decoder_init(decoder_ctx, type) < 0)
219 if ((ret = avcodec_open2(decoder_ctx, decoder, NULL)) < 0) {
220 fprintf(stderr, "Failed to open codec for stream #%u\n", video_stream);
224 /* open the file to dump raw data */
225 output_file = fopen(argv[3], "w+");
227 /* actual decoding and dump the raw data */
229 if ((ret = av_read_frame(input_ctx, &packet)) < 0)
232 if (video_stream == packet.stream_index)
233 ret = decode_write(decoder_ctx, &packet);
235 av_packet_unref(&packet);
238 /* flush the decoder */
241 ret = decode_write(decoder_ctx, &packet);
242 av_packet_unref(&packet);
246 avcodec_free_context(&decoder_ctx);
247 avformat_close_input(&input_ctx);
248 av_buffer_unref(&hw_device_ctx);