1 /*
2 * This file is part of FFmpeg.
3 *
4 * FFmpeg is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * FFmpeg is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with FFmpeg; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19 /* shared code for simple demux/decode tools */
20
21 #include <stdlib.h>
22 #include <string.h>
23
24 #include "decode_simple.h"
25
26 #include "libavformat/avformat.h"
27
28 #include "libavcodec/avcodec.h"
29 #include "libavcodec/packet.h"
30
31 #include "libavutil/dict.h"
32 #include "libavutil/error.h"
33 #include "libavutil/frame.h"
34
decode_read(DecodeContext * dc,int flush)35 static int decode_read(DecodeContext *dc, int flush)
36 {
37 const int ret_done = flush ? AVERROR_EOF : AVERROR(EAGAIN);
38 int ret = 0;
39
40 while (ret >= 0 &&
41 (dc->max_frames == 0 || dc->decoder->frame_number < dc->max_frames)) {
42 ret = avcodec_receive_frame(dc->decoder, dc->frame);
43 if (ret < 0) {
44 if (ret == AVERROR_EOF) {
45 int err = dc->process_frame(dc, NULL);
46 if (err < 0)
47 return err;
48 }
49
50 return (ret == ret_done) ? 0 : ret;
51 }
52
53 ret = dc->process_frame(dc, dc->frame);
54 av_frame_unref(dc->frame);
55 if (ret < 0)
56 return ret;
57
58 if (dc->max_frames && dc->decoder->frame_number == dc->max_frames)
59 return 1;
60 }
61
62 return (dc->max_frames == 0 || dc->decoder->frame_number < dc->max_frames) ? 0 : 1;
63 }
64
ds_run(DecodeContext * dc)65 int ds_run(DecodeContext *dc)
66 {
67 int ret;
68
69 ret = avcodec_open2(dc->decoder, NULL, &dc->decoder_opts);
70 if (ret < 0)
71 return ret;
72
73 while (ret >= 0) {
74 ret = av_read_frame(dc->demuxer, dc->pkt);
75 if (ret < 0)
76 goto flush;
77 if (dc->pkt->stream_index != dc->stream->index) {
78 av_packet_unref(dc->pkt);
79 continue;
80 }
81
82 ret = avcodec_send_packet(dc->decoder, dc->pkt);
83 if (ret < 0) {
84 fprintf(stderr, "Error decoding: %d\n", ret);
85 return ret;
86 }
87 av_packet_unref(dc->pkt);
88
89 ret = decode_read(dc, 0);
90 if (ret < 0) {
91 fprintf(stderr, "Error decoding: %d\n", ret);
92 return ret;
93 } else if (ret > 0)
94 return 0;
95 }
96
97 flush:
98 avcodec_send_packet(dc->decoder, NULL);
99 ret = decode_read(dc, 1);
100 if (ret < 0) {
101 fprintf(stderr, "Error flushing: %d\n", ret);
102 return ret;
103 }
104
105 return 0;
106 }
107
ds_free(DecodeContext * dc)108 void ds_free(DecodeContext *dc)
109 {
110 av_dict_free(&dc->decoder_opts);
111
112 av_frame_free(&dc->frame);
113 av_packet_free(&dc->pkt);
114
115 avcodec_free_context(&dc->decoder);
116 avformat_close_input(&dc->demuxer);
117 }
118
ds_open(DecodeContext * dc,const char * url,int stream_idx)119 int ds_open(DecodeContext *dc, const char *url, int stream_idx)
120 {
121 const AVCodec *codec;
122 int ret;
123
124 memset(dc, 0, sizeof(*dc));
125
126 dc->pkt = av_packet_alloc();
127 dc->frame = av_frame_alloc();
128 if (!dc->pkt || !dc->frame) {
129 ret = AVERROR(ENOMEM);
130 goto fail;
131 }
132
133 ret = avformat_open_input(&dc->demuxer, url, NULL, NULL);
134 if (ret < 0) {
135 fprintf(stderr, "Error opening input file: %d\n", ret);
136 return ret;
137 }
138
139 if (stream_idx < 0 || stream_idx >= dc->demuxer->nb_streams)
140 return AVERROR(EINVAL);
141
142 dc->stream = dc->demuxer->streams[stream_idx];
143
144 codec = avcodec_find_decoder(dc->stream->codecpar->codec_id);
145 if (!codec)
146 return AVERROR_DECODER_NOT_FOUND;
147
148 dc->decoder = avcodec_alloc_context3(codec);
149 if (!dc->decoder)
150 return AVERROR(ENOMEM);
151
152 return 0;
153
154 fail:
155 ds_free(dc);
156 return ret;
157 }
158