summaryrefslogtreecommitdiff
path: root/doc/examples/demuxing.c
diff options
context:
space:
mode:
Diffstat (limited to 'doc/examples/demuxing.c')
-rw-r--r--doc/examples/demuxing.c342
1 files changed, 342 insertions, 0 deletions
diff --git a/doc/examples/demuxing.c b/doc/examples/demuxing.c
new file mode 100644
index 0000000000..8a1b69bcf5
--- /dev/null
+++ b/doc/examples/demuxing.c
@@ -0,0 +1,342 @@
+/*
+ * Copyright (c) 2012 Stefano Sabatini
+ *
+ * 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
+ * libavformat demuxing API use example.
+ *
+ * Show how to use the libavformat and libavcodec API to demux and
+ * decode audio and video data.
+ * @example doc/examples/demuxing.c
+ */
+
+#include <libavutil/imgutils.h>
+#include <libavutil/samplefmt.h>
+#include <libavutil/timestamp.h>
+#include <libavformat/avformat.h>
+
+static AVFormatContext *fmt_ctx = NULL;
+static AVCodecContext *video_dec_ctx = NULL, *audio_dec_ctx;
+static AVStream *video_stream = NULL, *audio_stream = NULL;
+static const char *src_filename = NULL;
+static const char *video_dst_filename = NULL;
+static const char *audio_dst_filename = NULL;
+static FILE *video_dst_file = NULL;
+static FILE *audio_dst_file = NULL;
+
+static uint8_t *video_dst_data[4] = {NULL};
+static int video_dst_linesize[4];
+static int video_dst_bufsize;
+
+static uint8_t **audio_dst_data = NULL;
+static int audio_dst_linesize;
+static int audio_dst_bufsize;
+
+static int video_stream_idx = -1, audio_stream_idx = -1;
+static AVFrame *frame = NULL;
+static AVPacket pkt;
+static int video_frame_count = 0;
+static int audio_frame_count = 0;
+
+static int decode_packet(int *got_frame, int cached)
+{
+ int ret = 0;
+
+ if (pkt.stream_index == video_stream_idx) {
+ /* decode video frame */
+ ret = avcodec_decode_video2(video_dec_ctx, frame, got_frame, &pkt);
+ if (ret < 0) {
+ fprintf(stderr, "Error decoding video frame\n");
+ return ret;
+ }
+
+ if (*got_frame) {
+ printf("video_frame%s n:%d coded_n:%d pts:%s\n",
+ cached ? "(cached)" : "",
+ video_frame_count++, frame->coded_picture_number,
+ av_ts2timestr(frame->pts, &video_dec_ctx->time_base));
+
+ /* copy decoded frame to destination buffer:
+ * this is required since rawvideo expects non aligned data */
+ av_image_copy(video_dst_data, video_dst_linesize,
+ (const uint8_t **)(frame->data), frame->linesize,
+ video_dec_ctx->pix_fmt, video_dec_ctx->width, video_dec_ctx->height);
+
+ /* write to rawvideo file */
+ fwrite(video_dst_data[0], 1, video_dst_bufsize, video_dst_file);
+ }
+ } else if (pkt.stream_index == audio_stream_idx) {
+ /* decode audio frame */
+ ret = avcodec_decode_audio4(audio_dec_ctx, frame, got_frame, &pkt);
+ if (ret < 0) {
+ fprintf(stderr, "Error decoding audio frame\n");
+ return ret;
+ }
+
+ if (*got_frame) {
+ printf("audio_frame%s n:%d nb_samples:%d pts:%s\n",
+ cached ? "(cached)" : "",
+ audio_frame_count++, frame->nb_samples,
+ av_ts2timestr(frame->pts, &audio_dec_ctx->time_base));
+
+ ret = av_samples_alloc(audio_dst_data, &audio_dst_linesize, av_frame_get_channels(frame),
+ frame->nb_samples, frame->format, 1);
+ if (ret < 0) {
+ fprintf(stderr, "Could not allocate audio buffer\n");
+ return AVERROR(ENOMEM);
+ }
+
+ /* TODO: extend return code of the av_samples_* functions so that this call is not needed */
+ audio_dst_bufsize =
+ av_samples_get_buffer_size(NULL, av_frame_get_channels(frame),
+ frame->nb_samples, frame->format, 1);
+
+ /* copy audio data to destination buffer:
+ * this is required since rawaudio expects non aligned data */
+ av_samples_copy(audio_dst_data, frame->data, 0, 0,
+ frame->nb_samples, av_frame_get_channels(frame), frame->format);
+
+ /* write to rawaudio file */
+ fwrite(audio_dst_data[0], 1, audio_dst_bufsize, audio_dst_file);
+ av_freep(&audio_dst_data[0]);
+ }
+ }
+
+ return ret;
+}
+
+static int open_codec_context(int *stream_idx,
+ AVFormatContext *fmt_ctx, enum AVMediaType type)
+{
+ int ret;
+ AVStream *st;
+ AVCodecContext *dec_ctx = NULL;
+ AVCodec *dec = NULL;
+
+ ret = av_find_best_stream(fmt_ctx, type, -1, -1, NULL, 0);
+ if (ret < 0) {
+ fprintf(stderr, "Could not find %s stream in input file '%s'\n",
+ av_get_media_type_string(type), src_filename);
+ return ret;
+ } else {
+ *stream_idx = ret;
+ st = fmt_ctx->streams[*stream_idx];
+
+ /* find decoder for the stream */
+ dec_ctx = st->codec;
+ dec = avcodec_find_decoder(dec_ctx->codec_id);
+ if (!dec) {
+ fprintf(stderr, "Failed to find %s codec\n",
+ av_get_media_type_string(type));
+ return ret;
+ }
+
+ if ((ret = avcodec_open2(dec_ctx, dec, NULL)) < 0) {
+ fprintf(stderr, "Failed to open %s codec\n",
+ av_get_media_type_string(type));
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+static int get_format_from_sample_fmt(const char **fmt,
+ enum AVSampleFormat sample_fmt)
+{
+ int i;
+ struct sample_fmt_entry {
+ enum AVSampleFormat sample_fmt; const char *fmt_be, *fmt_le;
+ } sample_fmt_entries[] = {
+ { AV_SAMPLE_FMT_U8, "u8", "u8" },
+ { AV_SAMPLE_FMT_S16, "s16be", "s16le" },
+ { AV_SAMPLE_FMT_S32, "s32be", "s32le" },
+ { AV_SAMPLE_FMT_FLT, "f32be", "f32le" },
+ { AV_SAMPLE_FMT_DBL, "f64be", "f64le" },
+ };
+ *fmt = NULL;
+
+ for (i = 0; i < FF_ARRAY_ELEMS(sample_fmt_entries); i++) {
+ struct sample_fmt_entry *entry = &sample_fmt_entries[i];
+ if (sample_fmt == entry->sample_fmt) {
+ *fmt = AV_NE(entry->fmt_be, entry->fmt_le);
+ return 0;
+ }
+ }
+
+ fprintf(stderr,
+ "sample format %s is not supported as output format\n",
+ av_get_sample_fmt_name(sample_fmt));
+ return -1;
+}
+
+int main (int argc, char **argv)
+{
+ int ret = 0, got_frame;
+
+ if (argc != 4) {
+ fprintf(stderr, "usage: %s input_file video_output_file audio_output_file\n"
+ "API example program to show how to read frames from an input file.\n"
+ "This program reads frames from a file, decodes them, and writes decoded\n"
+ "video frames to a rawvideo file named video_output_file, and decoded\n"
+ "audio frames to a rawaudio file named audio_output_file.\n"
+ "\n", argv[0]);
+ exit(1);
+ }
+ src_filename = argv[1];
+ video_dst_filename = argv[2];
+ audio_dst_filename = argv[3];
+
+ /* register all formats and codecs */
+ av_register_all();
+
+ /* open input file, and allocate format context */
+ if (avformat_open_input(&fmt_ctx, src_filename, NULL, NULL) < 0) {
+ fprintf(stderr, "Could not open source file %s\n", src_filename);
+ exit(1);
+ }
+
+ /* retrieve stream information */
+ if (avformat_find_stream_info(fmt_ctx, NULL) < 0) {
+ fprintf(stderr, "Could not find stream information\n");
+ exit(1);
+ }
+
+ if (open_codec_context(&video_stream_idx, fmt_ctx, AVMEDIA_TYPE_VIDEO) >= 0) {
+ video_stream = fmt_ctx->streams[video_stream_idx];
+ video_dec_ctx = video_stream->codec;
+
+ video_dst_file = fopen(video_dst_filename, "wb");
+ if (!video_dst_file) {
+ fprintf(stderr, "Could not open destination file %s\n", video_dst_filename);
+ ret = 1;
+ goto end;
+ }
+
+ /* allocate image where the decoded image will be put */
+ ret = av_image_alloc(video_dst_data, video_dst_linesize,
+ video_dec_ctx->width, video_dec_ctx->height,
+ video_dec_ctx->pix_fmt, 1);
+ if (ret < 0) {
+ fprintf(stderr, "Could not allocate raw video buffer\n");
+ goto end;
+ }
+ video_dst_bufsize = ret;
+ }
+
+ if (open_codec_context(&audio_stream_idx, fmt_ctx, AVMEDIA_TYPE_AUDIO) >= 0) {
+ int nb_planes;
+
+ audio_stream = fmt_ctx->streams[audio_stream_idx];
+ audio_dec_ctx = audio_stream->codec;
+ audio_dst_file = fopen(audio_dst_filename, "wb");
+ if (!audio_dst_file) {
+ fprintf(stderr, "Could not open destination file %s\n", video_dst_filename);
+ ret = 1;
+ goto end;
+ }
+
+ nb_planes = av_sample_fmt_is_planar(audio_dec_ctx->sample_fmt) ?
+ audio_dec_ctx->channels : 1;
+ audio_dst_data = av_mallocz(sizeof(uint8_t *) * nb_planes);
+ if (!audio_dst_data) {
+ fprintf(stderr, "Could not allocate audio data buffers\n");
+ ret = AVERROR(ENOMEM);
+ goto end;
+ }
+ }
+
+ /* dump input information to stderr */
+ av_dump_format(fmt_ctx, 0, src_filename, 0);
+
+ if (!audio_stream && !video_stream) {
+ fprintf(stderr, "Could not find audio or video stream in the input, aborting\n");
+ ret = 1;
+ goto end;
+ }
+
+ frame = avcodec_alloc_frame();
+ if (!frame) {
+ fprintf(stderr, "Could not allocate frame\n");
+ ret = AVERROR(ENOMEM);
+ goto end;
+ }
+
+ /* initialize packet, set data to NULL, let the demuxer fill it */
+ av_init_packet(&pkt);
+ pkt.data = NULL;
+ pkt.size = 0;
+
+ if (video_stream)
+ printf("Demuxing video from file '%s' into '%s'\n", src_filename, video_dst_filename);
+ if (audio_stream)
+ printf("Demuxing audio from file '%s' into '%s'\n", src_filename, audio_dst_filename);
+
+ /* read frames from the file */
+ while (av_read_frame(fmt_ctx, &pkt) >= 0) {
+ decode_packet(&got_frame, 0);
+ av_free_packet(&pkt);
+ }
+
+ /* flush cached frames */
+ pkt.data = NULL;
+ pkt.size = 0;
+ do {
+ decode_packet(&got_frame, 1);
+ } while (got_frame);
+
+ printf("Demuxing succeeded.\n");
+
+ if (video_stream) {
+ printf("Play the output video file with the command:\n"
+ "ffplay -f rawvideo -pix_fmt %s -video_size %dx%d %s\n",
+ av_get_pix_fmt_name(video_dec_ctx->pix_fmt), video_dec_ctx->width, video_dec_ctx->height,
+ video_dst_filename);
+ }
+
+ if (audio_stream) {
+ const char *fmt;
+
+ if ((ret = get_format_from_sample_fmt(&fmt, audio_dec_ctx->sample_fmt)) < 0)
+ goto end;
+ printf("Play the output audio file with the command:\n"
+ "ffplay -f %s -ac %d -ar %d %s\n",
+ fmt, audio_dec_ctx->channels, audio_dec_ctx->sample_rate,
+ audio_dst_filename);
+ }
+
+end:
+ if (video_dec_ctx)
+ avcodec_close(video_dec_ctx);
+ if (audio_dec_ctx)
+ avcodec_close(audio_dec_ctx);
+ avformat_close_input(&fmt_ctx);
+ if (video_dst_file)
+ fclose(video_dst_file);
+ if (audio_dst_file)
+ fclose(audio_dst_file);
+ av_free(frame);
+ av_free(video_dst_data[0]);
+ av_free(audio_dst_data);
+
+ return ret < 0;
+}
View Lorry Controller Status