2 * Copyright (c) 2017 Jun Zhao
3 * Copyright (c) 2017 Kaixuan Liu
5 * HW Acceleration API (video decoding) decode sample
7 * Permission is hereby granted, free of charge, to any person obtaining a copy
8 * of this software and associated documentation files (the "Software"), to deal
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12 * furnished to do so, subject to the following conditions:
14 * The above copyright notice and this permission notice shall be included in
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28 * HW-Accelerated decoding example.
30 * @example hw_decode.c
31 * This example shows how to do HW-accelerated decoding with output
32 * frames from the HW video surfaces.
37 #include <libavcodec/avcodec.h>
38 #include <libavformat/avformat.h>
39 #include <libavutil/pixdesc.h>
40 #include <libavutil/hwcontext.h>
41 #include <libavutil/opt.h>
42 #include <libavutil/avassert.h>
43 #include <libavutil/imgutils.h>
45 static AVBufferRef *hw_device_ctx = NULL;
46 static enum AVPixelFormat hw_pix_fmt;
47 static FILE *output_file = NULL;
49 static int hw_decoder_init(AVCodecContext *ctx, const enum AVHWDeviceType type)
53 if ((err = av_hwdevice_ctx_create(&hw_device_ctx, type,
54 NULL, NULL, 0)) < 0) {
55 fprintf(stderr, "Failed to create specified HW device.\n");
58 ctx->hw_device_ctx = av_buffer_ref(hw_device_ctx);
63 static enum AVPixelFormat get_hw_format(AVCodecContext *ctx,
64 const enum AVPixelFormat *pix_fmts)
66 const enum AVPixelFormat *p;
68 for (p = pix_fmts; *p != -1; p++) {
73 fprintf(stderr, "Failed to get HW surface format.\n");
74 return AV_PIX_FMT_NONE;
77 static int decode_write(AVCodecContext *avctx, AVPacket *packet)
79 AVFrame *frame = NULL, *sw_frame = NULL;
80 AVFrame *tmp_frame = NULL;
81 uint8_t *buffer = NULL;
85 ret = avcodec_send_packet(avctx, packet);
87 fprintf(stderr, "Error during decoding\n");
92 if (!(frame = av_frame_alloc()) || !(sw_frame = av_frame_alloc())) {
93 fprintf(stderr, "Can not alloc frame\n");
94 ret = AVERROR(ENOMEM);
98 ret = avcodec_receive_frame(avctx, frame);
99 if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
100 av_frame_free(&frame);
101 av_frame_free(&sw_frame);
103 } else if (ret < 0) {
104 fprintf(stderr, "Error while decoding\n");
108 if (frame->format == hw_pix_fmt) {
109 /* retrieve data from GPU to CPU */
110 if ((ret = av_hwframe_transfer_data(sw_frame, frame, 0)) < 0) {
111 fprintf(stderr, "Error transferring the data to system memory\n");
114 tmp_frame = sw_frame;
118 size = av_image_get_buffer_size(tmp_frame->format, tmp_frame->width,
119 tmp_frame->height, 1);
120 buffer = av_malloc(size);
122 fprintf(stderr, "Can not alloc buffer\n");
123 ret = AVERROR(ENOMEM);
126 ret = av_image_copy_to_buffer(buffer, size,
127 (const uint8_t * const *)tmp_frame->data,
128 (const int *)tmp_frame->linesize, tmp_frame->format,
129 tmp_frame->width, tmp_frame->height, 1);
131 fprintf(stderr, "Can not copy image to buffer\n");
135 if ((ret = fwrite(buffer, 1, size, output_file)) < 0) {
136 fprintf(stderr, "Failed to dump raw data.\n");
141 av_frame_free(&frame);
142 av_frame_free(&sw_frame);
149 int main(int argc, char *argv[])
151 AVFormatContext *input_ctx = NULL;
152 int video_stream, ret;
153 AVStream *video = NULL;
154 AVCodecContext *decoder_ctx = NULL;
155 AVCodec *decoder = NULL;
157 enum AVHWDeviceType type;
161 fprintf(stderr, "Usage: %s <device type> <input file> <output file>\n", argv[0]);
165 type = av_hwdevice_find_type_by_name(argv[1]);
166 if (type == AV_HWDEVICE_TYPE_NONE) {
167 fprintf(stderr, "Device type %s is not supported.\n", argv[1]);
168 fprintf(stderr, "Available device types:");
169 while((type = av_hwdevice_iterate_types(type)) != AV_HWDEVICE_TYPE_NONE)
170 fprintf(stderr, " %s", av_hwdevice_get_type_name(type));
171 fprintf(stderr, "\n");
175 /* open the input file */
176 if (avformat_open_input(&input_ctx, argv[2], NULL, NULL) != 0) {
177 fprintf(stderr, "Cannot open input file '%s'\n", argv[2]);
181 if (avformat_find_stream_info(input_ctx, NULL) < 0) {
182 fprintf(stderr, "Cannot find input stream information.\n");
186 /* find the video stream information */
187 ret = av_find_best_stream(input_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, &decoder, 0);
189 fprintf(stderr, "Cannot find a video stream in the input file\n");
195 const AVCodecHWConfig *config = avcodec_get_hw_config(decoder, i);
197 fprintf(stderr, "Decoder %s does not support device type %s.\n",
198 decoder->name, av_hwdevice_get_type_name(type));
201 if (config->methods & AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX &&
202 config->device_type == type) {
203 hw_pix_fmt = config->pix_fmt;
208 if (!(decoder_ctx = avcodec_alloc_context3(decoder)))
209 return AVERROR(ENOMEM);
211 video = input_ctx->streams[video_stream];
212 if (avcodec_parameters_to_context(decoder_ctx, video->codecpar) < 0)
215 decoder_ctx->get_format = get_hw_format;
217 if (hw_decoder_init(decoder_ctx, type) < 0)
220 if ((ret = avcodec_open2(decoder_ctx, decoder, NULL)) < 0) {
221 fprintf(stderr, "Failed to open codec for stream #%u\n", video_stream);
225 /* open the file to dump raw data */
226 output_file = fopen(argv[3], "w+");
228 /* actual decoding and dump the raw data */
230 if ((ret = av_read_frame(input_ctx, &packet)) < 0)
233 if (video_stream == packet.stream_index)
234 ret = decode_write(decoder_ctx, &packet);
236 av_packet_unref(&packet);
239 /* flush the decoder */
242 ret = decode_write(decoder_ctx, &packet);
243 av_packet_unref(&packet);
247 avcodec_free_context(&decoder_ctx);
248 avformat_close_input(&input_ctx);
249 av_buffer_unref(&hw_device_ctx);