1 /*
2  * Copyright (c) 2017 Jun Zhao
3  * Copyright (c) 2017 Kaixuan Liu
4  *
5  * HW Acceleration API (video decoding) decode sample
6  *
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
9  * in the Software without restriction, including without limitation the rights
10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11  * copies of the Software, and to permit persons to whom the Software is
12  * furnished to do so, subject to the following conditions:
13  *
14  * The above copyright notice and this permission notice shall be included in
15  * all copies or substantial portions of the Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
23  * THE SOFTWARE.
24  */
25 
26 /**
27  * @file
28  * HW-Accelerated decoding example.
29  *
30  * @example hw_decode.c
31  * This example shows how to do HW-accelerated decoding with output
32  * frames from the HW video surfaces.
33  */
34 
35 #include <stdio.h>
36 
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>
44 
45 static AVBufferRef *hw_device_ctx = NULL;
46 static enum AVPixelFormat hw_pix_fmt;
47 static FILE *output_file = NULL;
48 
hw_decoder_init(AVCodecContext *ctx, const enum AVHWDeviceType type)49 static int hw_decoder_init(AVCodecContext *ctx, const enum AVHWDeviceType type)
50 {
51     int err = 0;
52 
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");
56         return err;
57     }
58     ctx->hw_device_ctx = av_buffer_ref(hw_device_ctx);
59 
60     return err;
61 }
62 
get_hw_format(AVCodecContext *ctx, const enum AVPixelFormat *pix_fmts)63 static enum AVPixelFormat get_hw_format(AVCodecContext *ctx,
64                                         const enum AVPixelFormat *pix_fmts)
65 {
66     const enum AVPixelFormat *p;
67 
68     for (p = pix_fmts; *p != -1; p++) {
69         if (*p == hw_pix_fmt)
70             return *p;
71     }
72 
73     fprintf(stderr, "Failed to get HW surface format.\n");
74     return AV_PIX_FMT_NONE;
75 }
76 
decode_write(AVCodecContext *avctx, AVPacket *packet)77 static int decode_write(AVCodecContext *avctx, AVPacket *packet)
78 {
79     AVFrame *frame = NULL, *sw_frame = NULL;
80     AVFrame *tmp_frame = NULL;
81     uint8_t *buffer = NULL;
82     int size;
83     int ret = 0;
84 
85     ret = avcodec_send_packet(avctx, packet);
86     if (ret < 0) {
87         fprintf(stderr, "Error during decoding\n");
88         return ret;
89     }
90 
91     while (1) {
92         if (!(frame = av_frame_alloc()) || !(sw_frame = av_frame_alloc())) {
93             fprintf(stderr, "Can not alloc frame\n");
94             ret = AVERROR(ENOMEM);
95             goto fail;
96         }
97 
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);
102             return 0;
103         } else if (ret < 0) {
104             fprintf(stderr, "Error while decoding\n");
105             goto fail;
106         }
107 
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");
112                 goto fail;
113             }
114             tmp_frame = sw_frame;
115         } else
116             tmp_frame = frame;
117 
118         size = av_image_get_buffer_size(tmp_frame->format, tmp_frame->width,
119                                         tmp_frame->height, 1);
120         buffer = av_malloc(size);
121         if (!buffer) {
122             fprintf(stderr, "Can not alloc buffer\n");
123             ret = AVERROR(ENOMEM);
124             goto fail;
125         }
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);
130         if (ret < 0) {
131             fprintf(stderr, "Can not copy image to buffer\n");
132             goto fail;
133         }
134 
135         if ((ret = fwrite(buffer, 1, size, output_file)) < 0) {
136             fprintf(stderr, "Failed to dump raw data.\n");
137             goto fail;
138         }
139 
140     fail:
141         av_frame_free(&frame);
142         av_frame_free(&sw_frame);
143         av_freep(&buffer);
144         if (ret < 0)
145             return ret;
146     }
147 }
148 
main(int argc, char *argv[])149 int main(int argc, char *argv[])
150 {
151     AVFormatContext *input_ctx = NULL;
152     int video_stream, ret;
153     AVStream *video = NULL;
154     AVCodecContext *decoder_ctx = NULL;
155     const AVCodec *decoder = NULL;
156     AVPacket *packet = NULL;
157     enum AVHWDeviceType type;
158     int i;
159 
160     if (argc < 4) {
161         fprintf(stderr, "Usage: %s <device type> <input file> <output file>\n", argv[0]);
162         return -1;
163     }
164 
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");
172         return -1;
173     }
174 
175     packet = av_packet_alloc();
176     if (!packet) {
177         fprintf(stderr, "Failed to allocate AVPacket\n");
178         return -1;
179     }
180 
181     /* open the input file */
182     if (avformat_open_input(&input_ctx, argv[2], NULL, NULL) != 0) {
183         fprintf(stderr, "Cannot open input file '%s'\n", argv[2]);
184         return -1;
185     }
186 
187     if (avformat_find_stream_info(input_ctx, NULL) < 0) {
188         fprintf(stderr, "Cannot find input stream information.\n");
189         return -1;
190     }
191 
192     /* find the video stream information */
193     ret = av_find_best_stream(input_ctx, AVMEDIA_TYPE_VIDEO, -1, -1, &decoder, 0);
194     if (ret < 0) {
195         fprintf(stderr, "Cannot find a video stream in the input file\n");
196         return -1;
197     }
198     video_stream = ret;
199 
200     for (i = 0;; i++) {
201         const AVCodecHWConfig *config = avcodec_get_hw_config(decoder, i);
202         if (!config) {
203             fprintf(stderr, "Decoder %s does not support device type %s.\n",
204                     decoder->name, av_hwdevice_get_type_name(type));
205             return -1;
206         }
207         if (config->methods & AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX &&
208             config->device_type == type) {
209             hw_pix_fmt = config->pix_fmt;
210             break;
211         }
212     }
213 
214     if (!(decoder_ctx = avcodec_alloc_context3(decoder)))
215         return AVERROR(ENOMEM);
216 
217     video = input_ctx->streams[video_stream];
218     if (avcodec_parameters_to_context(decoder_ctx, video->codecpar) < 0)
219         return -1;
220 
221     decoder_ctx->get_format  = get_hw_format;
222 
223     if (hw_decoder_init(decoder_ctx, type) < 0)
224         return -1;
225 
226     if ((ret = avcodec_open2(decoder_ctx, decoder, NULL)) < 0) {
227         fprintf(stderr, "Failed to open codec for stream #%u\n", video_stream);
228         return -1;
229     }
230 
231     /* open the file to dump raw data */
232     output_file = fopen(argv[3], "w+b");
233 
234     /* actual decoding and dump the raw data */
235     while (ret >= 0) {
236         if ((ret = av_read_frame(input_ctx, packet)) < 0)
237             break;
238 
239         if (video_stream == packet->stream_index)
240             ret = decode_write(decoder_ctx, packet);
241 
242         av_packet_unref(packet);
243     }
244 
245     /* flush the decoder */
246     ret = decode_write(decoder_ctx, NULL);
247 
248     if (output_file)
249         fclose(output_file);
250     av_packet_free(&packet);
251     avcodec_free_context(&decoder_ctx);
252     avformat_close_input(&input_ctx);
253     av_buffer_unref(&hw_device_ctx);
254 
255     return 0;
256 }
257