examples: rename muxing to mux

1 files changed, 645 insertions, 0 deletions

diff --git a/doc/examples/mux.c b/doc/examples/mux.c
new file mode 100644
index 0000000000..e3062c5003
--- /dev/null
+++ b/doc/examples/mux.c
@@ -0,0 +1,645 @@
+/*
+ * Copyright (c) 2003 Fabrice Bellard
+ *
+ * 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 API example.
+ *
+ * Output a media file in any supported libavformat format. The default
+ * codecs are used.
+ * @example mux.c
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <math.h>
+
+#include <libavutil/avassert.h>
+#include <libavutil/channel_layout.h>
+#include <libavutil/opt.h>
+#include <libavutil/mathematics.h>
+#include <libavutil/timestamp.h>
+#include <libavcodec/avcodec.h>
+#include <libavformat/avformat.h>
+#include <libswscale/swscale.h>
+#include <libswresample/swresample.h>
+
+#define STREAM_DURATION   10.0
+#define STREAM_FRAME_RATE 25 /* 25 images/s */
+#define STREAM_PIX_FMT    AV_PIX_FMT_YUV420P /* default pix_fmt */
+
+#define SCALE_FLAGS SWS_BICUBIC
+
+// a wrapper around a single output AVStream
+typedef struct OutputStream {
+    AVStream *st;
+    AVCodecContext *enc;
+
+    /* pts of the next frame that will be generated */
+    int64_t next_pts;
+    int samples_count;
+
+    AVFrame *frame;
+    AVFrame *tmp_frame;
+
+    AVPacket *tmp_pkt;
+
+    float t, tincr, tincr2;
+
+    struct SwsContext *sws_ctx;
+    struct SwrContext *swr_ctx;
+} OutputStream;
+
+static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt)
+{
+    AVRational *time_base = &fmt_ctx->streams[pkt->stream_index]->time_base;
+
+    printf("pts:%s pts_time:%s dts:%s dts_time:%s duration:%s duration_time:%s stream_index:%d\n",
+           av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, time_base),
+           av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, time_base),
+           av_ts2str(pkt->duration), av_ts2timestr(pkt->duration, time_base),
+           pkt->stream_index);
+}
+
+static int write_frame(AVFormatContext *fmt_ctx, AVCodecContext *c,
+                       AVStream *st, AVFrame *frame, AVPacket *pkt)
+{
+    int ret;
+
+    // send the frame to the encoder
+    ret = avcodec_send_frame(c, frame);
+    if (ret < 0) {
+        fprintf(stderr, "Error sending a frame to the encoder: %s\n",
+                av_err2str(ret));
+        exit(1);
+    }
+
+    while (ret >= 0) {
+        ret = avcodec_receive_packet(c, pkt);
+        if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
+            break;
+        else if (ret < 0) {
+            fprintf(stderr, "Error encoding a frame: %s\n", av_err2str(ret));
+            exit(1);
+        }
+
+        /* rescale output packet timestamp values from codec to stream timebase */
+        av_packet_rescale_ts(pkt, c->time_base, st->time_base);
+        pkt->stream_index = st->index;
+
+        /* Write the compressed frame to the media file. */
+        log_packet(fmt_ctx, pkt);
+        ret = av_interleaved_write_frame(fmt_ctx, pkt);
+        /* pkt is now blank (av_interleaved_write_frame() takes ownership of
+         * its contents and resets pkt), so that no unreferencing is necessary.
+         * This would be different if one used av_write_frame(). */
+        if (ret < 0) {
+            fprintf(stderr, "Error while writing output packet: %s\n", av_err2str(ret));
+            exit(1);
+        }
+    }
+
+    return ret == AVERROR_EOF ? 1 : 0;
+}
+
+/* Add an output stream. */
+static void add_stream(OutputStream *ost, AVFormatContext *oc,
+                       const AVCodec **codec,
+                       enum AVCodecID codec_id)
+{
+    AVCodecContext *c;
+    int i;
+
+    /* find the encoder */
+    *codec = avcodec_find_encoder(codec_id);
+    if (!(*codec)) {
+        fprintf(stderr, "Could not find encoder for '%s'\n",
+                avcodec_get_name(codec_id));
+        exit(1);
+    }
+
+    ost->tmp_pkt = av_packet_alloc();
+    if (!ost->tmp_pkt) {
+        fprintf(stderr, "Could not allocate AVPacket\n");
+        exit(1);
+    }
+
+    ost->st = avformat_new_stream(oc, NULL);
+    if (!ost->st) {
+        fprintf(stderr, "Could not allocate stream\n");
+        exit(1);
+    }
+    ost->st->id = oc->nb_streams-1;
+    c = avcodec_alloc_context3(*codec);
+    if (!c) {
+        fprintf(stderr, "Could not alloc an encoding context\n");
+        exit(1);
+    }
+    ost->enc = c;
+
+    switch ((*codec)->type) {
+    case AVMEDIA_TYPE_AUDIO:
+        c->sample_fmt  = (*codec)->sample_fmts ?
+            (*codec)->sample_fmts[0] : AV_SAMPLE_FMT_FLTP;
+        c->bit_rate    = 64000;
+        c->sample_rate = 44100;
+        if ((*codec)->supported_samplerates) {
+            c->sample_rate = (*codec)->supported_samplerates[0];
+            for (i = 0; (*codec)->supported_samplerates[i]; i++) {
+                if ((*codec)->supported_samplerates[i] == 44100)
+                    c->sample_rate = 44100;
+            }
+        }
+        av_channel_layout_copy(&c->ch_layout, &(AVChannelLayout)AV_CHANNEL_LAYOUT_STEREO);
+        ost->st->time_base = (AVRational){ 1, c->sample_rate };
+        break;
+
+    case AVMEDIA_TYPE_VIDEO:
+        c->codec_id = codec_id;
+
+        c->bit_rate = 400000;
+        /* Resolution must be a multiple of two. */
+        c->width    = 352;
+        c->height   = 288;
+        /* timebase: This is the fundamental unit of time (in seconds) in terms
+         * of which frame timestamps are represented. For fixed-fps content,
+         * timebase should be 1/framerate and timestamp increments should be
+         * identical to 1. */
+        ost->st->time_base = (AVRational){ 1, STREAM_FRAME_RATE };
+        c->time_base       = ost->st->time_base;
+
+        c->gop_size      = 12; /* emit one intra frame every twelve frames at most */
+        c->pix_fmt       = STREAM_PIX_FMT;
+        if (c->codec_id == AV_CODEC_ID_MPEG2VIDEO) {
+            /* just for testing, we also add B-frames */
+            c->max_b_frames = 2;
+        }
+        if (c->codec_id == AV_CODEC_ID_MPEG1VIDEO) {
+            /* Needed to avoid using macroblocks in which some coeffs overflow.
+             * This does not happen with normal video, it just happens here as
+             * the motion of the chroma plane does not match the luma plane. */
+            c->mb_decision = 2;
+        }
+        break;
+
+    default:
+        break;
+    }
+
+    /* Some formats want stream headers to be separate. */
+    if (oc->oformat->flags & AVFMT_GLOBALHEADER)
+        c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
+}
+
+/**************************************************************/
+/* audio output */
+
+static AVFrame *alloc_audio_frame(enum AVSampleFormat sample_fmt,
+                                  const AVChannelLayout *channel_layout,
+                                  int sample_rate, int nb_samples)
+{
+    AVFrame *frame = av_frame_alloc();
+    if (!frame) {
+        fprintf(stderr, "Error allocating an audio frame\n");
+        exit(1);
+    }
+
+    frame->format = sample_fmt;
+    av_channel_layout_copy(&frame->ch_layout, channel_layout);
+    frame->sample_rate = sample_rate;
+    frame->nb_samples = nb_samples;
+
+    if (nb_samples) {
+        if (av_frame_get_buffer(frame, 0) < 0) {
+            fprintf(stderr, "Error allocating an audio buffer\n");
+            exit(1);
+        }
+    }
+
+    return frame;
+}
+
+static void open_audio(AVFormatContext *oc, const AVCodec *codec,
+                       OutputStream *ost, AVDictionary *opt_arg)
+{
+    AVCodecContext *c;
+    int nb_samples;
+    int ret;
+    AVDictionary *opt = NULL;
+
+    c = ost->enc;
+
+    /* open it */
+    av_dict_copy(&opt, opt_arg, 0);
+    ret = avcodec_open2(c, codec, &opt);
+    av_dict_free(&opt);
+    if (ret < 0) {
+        fprintf(stderr, "Could not open audio codec: %s\n", av_err2str(ret));
+        exit(1);
+    }
+
+    /* init signal generator */
+    ost->t     = 0;
+    ost->tincr = 2 * M_PI * 110.0 / c->sample_rate;
+    /* increment frequency by 110 Hz per second */
+    ost->tincr2 = 2 * M_PI * 110.0 / c->sample_rate / c->sample_rate;
+
+    if (c->codec->capabilities & AV_CODEC_CAP_VARIABLE_FRAME_SIZE)
+        nb_samples = 10000;
+    else
+        nb_samples = c->frame_size;
+
+    ost->frame     = alloc_audio_frame(c->sample_fmt, &c->ch_layout,
+                                       c->sample_rate, nb_samples);
+    ost->tmp_frame = alloc_audio_frame(AV_SAMPLE_FMT_S16, &c->ch_layout,
+                                       c->sample_rate, nb_samples);
+
+    /* copy the stream parameters to the muxer */
+    ret = avcodec_parameters_from_context(ost->st->codecpar, c);
+    if (ret < 0) {
+        fprintf(stderr, "Could not copy the stream parameters\n");
+        exit(1);
+    }
+
+    /* create resampler context */
+    ost->swr_ctx = swr_alloc();
+    if (!ost->swr_ctx) {
+        fprintf(stderr, "Could not allocate resampler context\n");
+        exit(1);
+    }
+
+    /* set options */
+    av_opt_set_chlayout  (ost->swr_ctx, "in_chlayout",       &c->ch_layout,      0);
+    av_opt_set_int       (ost->swr_ctx, "in_sample_rate",     c->sample_rate,    0);
+    av_opt_set_sample_fmt(ost->swr_ctx, "in_sample_fmt",      AV_SAMPLE_FMT_S16, 0);
+    av_opt_set_chlayout  (ost->swr_ctx, "out_chlayout",      &c->ch_layout,      0);
+    av_opt_set_int       (ost->swr_ctx, "out_sample_rate",    c->sample_rate,    0);
+    av_opt_set_sample_fmt(ost->swr_ctx, "out_sample_fmt",     c->sample_fmt,     0);
+
+    /* initialize the resampling context */
+    if ((ret = swr_init(ost->swr_ctx)) < 0) {
+        fprintf(stderr, "Failed to initialize the resampling context\n");
+        exit(1);
+    }
+}
+
+/* Prepare a 16 bit dummy audio frame of 'frame_size' samples and
+ * 'nb_channels' channels. */
+static AVFrame *get_audio_frame(OutputStream *ost)
+{
+    AVFrame *frame = ost->tmp_frame;
+    int j, i, v;
+    int16_t *q = (int16_t*)frame->data[0];
+
+    /* check if we want to generate more frames */
+    if (av_compare_ts(ost->next_pts, ost->enc->time_base,
+                      STREAM_DURATION, (AVRational){ 1, 1 }) > 0)
+        return NULL;
+
+    for (j = 0; j <frame->nb_samples; j++) {
+        v = (int)(sin(ost->t) * 10000);
+        for (i = 0; i < ost->enc->ch_layout.nb_channels; i++)
+            *q++ = v;
+        ost->t     += ost->tincr;
+        ost->tincr += ost->tincr2;
+    }
+
+    frame->pts = ost->next_pts;
+    ost->next_pts  += frame->nb_samples;
+
+    return frame;
+}
+
+/*
+ * encode one audio frame and send it to the muxer
+ * return 1 when encoding is finished, 0 otherwise
+ */
+static int write_audio_frame(AVFormatContext *oc, OutputStream *ost)
+{
+    AVCodecContext *c;
+    AVFrame *frame;
+    int ret;
+    int dst_nb_samples;
+
+    c = ost->enc;
+
+    frame = get_audio_frame(ost);
+
+    if (frame) {
+        /* convert samples from native format to destination codec format, using the resampler */
+        /* compute destination number of samples */
+        dst_nb_samples = av_rescale_rnd(swr_get_delay(ost->swr_ctx, c->sample_rate) + frame->nb_samples,
+                                        c->sample_rate, c->sample_rate, AV_ROUND_UP);
+        av_assert0(dst_nb_samples == frame->nb_samples);
+
+        /* when we pass a frame to the encoder, it may keep a reference to it
+         * internally;
+         * make sure we do not overwrite it here
+         */
+        ret = av_frame_make_writable(ost->frame);
+        if (ret < 0)
+            exit(1);
+
+        /* convert to destination format */
+        ret = swr_convert(ost->swr_ctx,
+                          ost->frame->data, dst_nb_samples,
+                          (const uint8_t **)frame->data, frame->nb_samples);
+        if (ret < 0) {
+            fprintf(stderr, "Error while converting\n");
+            exit(1);
+        }
+        frame = ost->frame;
+
+        frame->pts = av_rescale_q(ost->samples_count, (AVRational){1, c->sample_rate}, c->time_base);
+        ost->samples_count += dst_nb_samples;
+    }
+
+    return write_frame(oc, c, ost->st, frame, ost->tmp_pkt);
+}
+
+/**************************************************************/
+/* video output */
+
+static AVFrame *alloc_picture(enum AVPixelFormat pix_fmt, int width, int height)
+{
+    AVFrame *picture;
+    int ret;
+
+    picture = av_frame_alloc();
+    if (!picture)
+        return NULL;
+
+    picture->format = pix_fmt;
+    picture->width  = width;
+    picture->height = height;
+
+    /* allocate the buffers for the frame data */
+    ret = av_frame_get_buffer(picture, 0);
+    if (ret < 0) {
+        fprintf(stderr, "Could not allocate frame data.\n");
+        exit(1);
+    }
+
+    return picture;
+}
+
+static void open_video(AVFormatContext *oc, const AVCodec *codec,
+                       OutputStream *ost, AVDictionary *opt_arg)
+{
+    int ret;
+    AVCodecContext *c = ost->enc;
+    AVDictionary *opt = NULL;
+
+    av_dict_copy(&opt, opt_arg, 0);
+
+    /* open the codec */
+    ret = avcodec_open2(c, codec, &opt);
+    av_dict_free(&opt);
+    if (ret < 0) {
+        fprintf(stderr, "Could not open video codec: %s\n", av_err2str(ret));
+        exit(1);
+    }
+
+    /* allocate and init a re-usable frame */
+    ost->frame = alloc_picture(c->pix_fmt, c->width, c->height);
+    if (!ost->frame) {
+        fprintf(stderr, "Could not allocate video frame\n");
+        exit(1);
+    }
+
+    /* If the output format is not YUV420P, then a temporary YUV420P
+     * picture is needed too. It is then converted to the required
+     * output format. */
+    ost->tmp_frame = NULL;
+    if (c->pix_fmt != AV_PIX_FMT_YUV420P) {
+        ost->tmp_frame = alloc_picture(AV_PIX_FMT_YUV420P, c->width, c->height);
+        if (!ost->tmp_frame) {
+            fprintf(stderr, "Could not allocate temporary picture\n");
+            exit(1);
+        }
+    }
+
+    /* copy the stream parameters to the muxer */
+    ret = avcodec_parameters_from_context(ost->st->codecpar, c);
+    if (ret < 0) {
+        fprintf(stderr, "Could not copy the stream parameters\n");
+        exit(1);
+    }
+}
+
+/* Prepare a dummy image. */
+static void fill_yuv_image(AVFrame *pict, int frame_index,
+                           int width, int height)
+{
+    int x, y, i;
+
+    i = frame_index;
+
+    /* Y */
+    for (y = 0; y < height; y++)
+        for (x = 0; x < width; x++)
+            pict->data[0][y * pict->linesize[0] + x] = x + y + i * 3;
+
+    /* Cb and Cr */
+    for (y = 0; y < height / 2; y++) {
+        for (x = 0; x < width / 2; x++) {
+            pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2;
+            pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5;
+        }
+    }
+}
+
+static AVFrame *get_video_frame(OutputStream *ost)
+{
+    AVCodecContext *c = ost->enc;
+
+    /* check if we want to generate more frames */
+    if (av_compare_ts(ost->next_pts, c->time_base,
+                      STREAM_DURATION, (AVRational){ 1, 1 }) > 0)
+        return NULL;
+
+    /* when we pass a frame to the encoder, it may keep a reference to it
+     * internally; make sure we do not overwrite it here */
+    if (av_frame_make_writable(ost->frame) < 0)
+        exit(1);
+
+    if (c->pix_fmt != AV_PIX_FMT_YUV420P) {
+        /* as we only generate a YUV420P picture, we must convert it
+         * to the codec pixel format if needed */
+        if (!ost->sws_ctx) {
+            ost->sws_ctx = sws_getContext(c->width, c->height,
+                                          AV_PIX_FMT_YUV420P,
+                                          c->width, c->height,
+                                          c->pix_fmt,
+                                          SCALE_FLAGS, NULL, NULL, NULL);
+            if (!ost->sws_ctx) {
+                fprintf(stderr,
+                        "Could not initialize the conversion context\n");
+                exit(1);
+            }
+        }
+        fill_yuv_image(ost->tmp_frame, ost->next_pts, c->width, c->height);
+        sws_scale(ost->sws_ctx, (const uint8_t * const *) ost->tmp_frame->data,
+                  ost->tmp_frame->linesize, 0, c->height, ost->frame->data,
+                  ost->frame->linesize);
+    } else {
+        fill_yuv_image(ost->frame, ost->next_pts, c->width, c->height);
+    }
+
+    ost->frame->pts = ost->next_pts++;
+
+    return ost->frame;
+}
+
+/*
+ * encode one video frame and send it to the muxer
+ * return 1 when encoding is finished, 0 otherwise
+ */
+static int write_video_frame(AVFormatContext *oc, OutputStream *ost)
+{
+    return write_frame(oc, ost->enc, ost->st, get_video_frame(ost), ost->tmp_pkt);
+}
+
+static void close_stream(AVFormatContext *oc, OutputStream *ost)
+{
+    avcodec_free_context(&ost->enc);
+    av_frame_free(&ost->frame);
+    av_frame_free(&ost->tmp_frame);
+    av_packet_free(&ost->tmp_pkt);
+    sws_freeContext(ost->sws_ctx);
+    swr_free(&ost->swr_ctx);
+}
+
+/**************************************************************/
+/* media file output */
+
+int main(int argc, char **argv)
+{
+    OutputStream video_st = { 0 }, audio_st = { 0 };
+    const AVOutputFormat *fmt;
+    const char *filename;
+    AVFormatContext *oc;
+    const AVCodec *audio_codec, *video_codec;
+    int ret;
+    int have_video = 0, have_audio = 0;
+    int encode_video = 0, encode_audio = 0;
+    AVDictionary *opt = NULL;
+    int i;
+
+    if (argc < 2) {
+        printf("usage: %s output_file\n"
+               "API example program to output a media file with libavformat.\n"
+               "This program generates a synthetic audio and video stream, encodes and\n"
+               "muxes them into a file named output_file.\n"
+               "The output format is automatically guessed according to the file extension.\n"
+               "Raw images can also be output by using '%%d' in the filename.\n"
+               "\n", argv[0]);
+        return 1;
+    }
+
+    filename = argv[1];
+    for (i = 2; i+1 < argc; i+=2) {
+        if (!strcmp(argv[i], "-flags") || !strcmp(argv[i], "-fflags"))
+            av_dict_set(&opt, argv[i]+1, argv[i+1], 0);
+    }
+
+    /* allocate the output media context */
+    avformat_alloc_output_context2(&oc, NULL, NULL, filename);
+    if (!oc) {
+        printf("Could not deduce output format from file extension: using MPEG.\n");
+        avformat_alloc_output_context2(&oc, NULL, "mpeg", filename);
+    }
+    if (!oc)
+        return 1;
+
+    fmt = oc->oformat;
+
+    /* Add the audio and video streams using the default format codecs
+     * and initialize the codecs. */
+    if (fmt->video_codec != AV_CODEC_ID_NONE) {
+        add_stream(&video_st, oc, &video_codec, fmt->video_codec);
+        have_video = 1;
+        encode_video = 1;
+    }
+    if (fmt->audio_codec != AV_CODEC_ID_NONE) {
+        add_stream(&audio_st, oc, &audio_codec, fmt->audio_codec);
+        have_audio = 1;
+        encode_audio = 1;
+    }
+
+    /* Now that all the parameters are set, we can open the audio and
+     * video codecs and allocate the necessary encode buffers. */
+    if (have_video)
+        open_video(oc, video_codec, &video_st, opt);
+
+    if (have_audio)
+        open_audio(oc, audio_codec, &audio_st, opt);
+
+    av_dump_format(oc, 0, filename, 1);
+
+    /* open the output file, if needed */
+    if (!(fmt->flags & AVFMT_NOFILE)) {
+        ret = avio_open(&oc->pb, filename, AVIO_FLAG_WRITE);
+        if (ret < 0) {
+            fprintf(stderr, "Could not open '%s': %s\n", filename,
+                    av_err2str(ret));
+            return 1;
+        }
+    }
+
+    /* Write the stream header, if any. */
+    ret = avformat_write_header(oc, &opt);
+    if (ret < 0) {
+        fprintf(stderr, "Error occurred when opening output file: %s\n",
+                av_err2str(ret));
+        return 1;
+    }
+
+    while (encode_video || encode_audio) {
+        /* select the stream to encode */
+        if (encode_video &&
+            (!encode_audio || av_compare_ts(video_st.next_pts, video_st.enc->time_base,
+                                            audio_st.next_pts, audio_st.enc->time_base) <= 0)) {
+            encode_video = !write_video_frame(oc, &video_st);
+        } else {
+            encode_audio = !write_audio_frame(oc, &audio_st);
+        }
+    }
+
+    av_write_trailer(oc);
+
+    /* Close each codec. */
+    if (have_video)
+        close_stream(oc, &video_st);
+    if (have_audio)
+        close_stream(oc, &audio_st);
+
+    if (!(fmt->flags & AVFMT_NOFILE))
+        /* Close the output file. */
+        avio_closep(&oc->pb);
+
+    /* free the stream */
+    avformat_free_context(oc);
+
+    return 0;
+}