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output example: use OutputStream for audio streams as well

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This commit is contained in:
Anton Khirnov 2014-06-24 08:56:27 +02:00
parent 5e7b125b6a
commit edd5f95764
1 changed files with 39 additions and 42 deletions
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81
doc/examples/output.c
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@ -53,21 +53,21 @@ typedef struct OutputStream {
AVFrame *frame; AVFrame *frame;
AVFrame *tmp_frame; AVFrame *tmp_frame;
float t, tincr, tincr2;
int audio_input_frame_size;
} OutputStream; } OutputStream;
/**************************************************************/ /**************************************************************/
/* audio output */ /* audio output */
static float t, tincr, tincr2;
static int audio_input_frame_size;
/* /*
* add an audio output stream * add an audio output stream
*/ */
static AVStream *add_audio_stream(AVFormatContext *oc, enum AVCodecID codec_id) static void add_audio_stream(OutputStream *ost, AVFormatContext *oc,
enum AVCodecID codec_id)
{ {
AVCodecContext *c; AVCodecContext *c;
AVStream *st;
AVCodec *codec; AVCodec *codec;
/* find the audio encoder */ /* find the audio encoder */
@ -77,13 +77,13 @@ static AVStream *add_audio_stream(AVFormatContext *oc, enum AVCodecID codec_id)
exit(1); exit(1);
} }
st = avformat_new_stream(oc, codec); ost->st = avformat_new_stream(oc, codec);
if (!st) { if (!ost->st) {
fprintf(stderr, "Could not alloc stream\n"); fprintf(stderr, "Could not alloc stream\n");
exit(1); exit(1);
} }
c = st->codec; c = ost->st->codec;
/* put sample parameters */ /* put sample parameters */
c->sample_fmt = AV_SAMPLE_FMT_S16; c->sample_fmt = AV_SAMPLE_FMT_S16;
@ -95,15 +95,13 @@ static AVStream *add_audio_stream(AVFormatContext *oc, enum AVCodecID codec_id)
// some formats want stream headers to be separate // some formats want stream headers to be separate
if (oc->oformat->flags & AVFMT_GLOBALHEADER) if (oc->oformat->flags & AVFMT_GLOBALHEADER)
c->flags |= CODEC_FLAG_GLOBAL_HEADER; c->flags |= CODEC_FLAG_GLOBAL_HEADER;
return st;
} }
static void open_audio(AVFormatContext *oc, AVStream *st) static void open_audio(AVFormatContext *oc, OutputStream *ost)
{ {
AVCodecContext *c; AVCodecContext *c;
c = st->codec; c = ost->st->codec;
/* open it */ /* open it */
if (avcodec_open2(c, NULL, NULL) < 0) { if (avcodec_open2(c, NULL, NULL) < 0) {
@ -112,20 +110,20 @@ static void open_audio(AVFormatContext *oc, AVStream *st)
} }
/* init signal generator */ /* init signal generator */
t = 0; ost->t = 0;
tincr = 2 * M_PI * 110.0 / c->sample_rate; ost->tincr = 2 * M_PI * 110.0 / c->sample_rate;
/* increment frequency by 110 Hz per second */ /* increment frequency by 110 Hz per second */
tincr2 = 2 * M_PI * 110.0 / c->sample_rate / c->sample_rate; ost->tincr2 = 2 * M_PI * 110.0 / c->sample_rate / c->sample_rate;
if (c->codec->capabilities & CODEC_CAP_VARIABLE_FRAME_SIZE) if (c->codec->capabilities & CODEC_CAP_VARIABLE_FRAME_SIZE)
audio_input_frame_size = 10000; ost->audio_input_frame_size = 10000;
else else
audio_input_frame_size = c->frame_size; ost->audio_input_frame_size = c->frame_size;
} }
/* Prepare a 16 bit dummy audio frame of 'frame_size' samples and /* Prepare a 16 bit dummy audio frame of 'frame_size' samples and
* 'nb_channels' channels. */ * 'nb_channels' channels. */
static void get_audio_frame(AVFrame *frame, int nb_channels) static void get_audio_frame(OutputStream *ost, AVFrame *frame, int nb_channels)
{ {
int j, i, v, ret; int j, i, v, ret;
int16_t *q = (int16_t*)frame->data[0]; int16_t *q = (int16_t*)frame->data[0];
@ -139,15 +137,15 @@ static void get_audio_frame(AVFrame *frame, int nb_channels)
exit(1); exit(1);
for (j = 0; j < frame->nb_samples; j++) { for (j = 0; j < frame->nb_samples; j++) {
v = (int)(sin(t) * 10000); v = (int)(sin(ost->t) * 10000);
for (i = 0; i < nb_channels; i++) for (i = 0; i < nb_channels; i++)
*q++ = v; *q++ = v;
t += tincr; ost->t += ost->tincr;
tincr += tincr2; ost->tincr += ost->tincr2;
} }
} }
static void write_audio_frame(AVFormatContext *oc, AVStream *st) static void write_audio_frame(AVFormatContext *oc, OutputStream *ost)
{ {
AVCodecContext *c; AVCodecContext *c;
AVPacket pkt = { 0 }; // data and size must be 0; AVPacket pkt = { 0 }; // data and size must be 0;
@ -155,10 +153,10 @@ static void write_audio_frame(AVFormatContext *oc, AVStream *st)
int got_packet, ret; int got_packet, ret;
av_init_packet(&pkt); av_init_packet(&pkt);
c = st->codec; c = ost->st->codec;
frame->sample_rate = c->sample_rate; frame->sample_rate = c->sample_rate;
frame->nb_samples = audio_input_frame_size; frame->nb_samples = ost->audio_input_frame_size;
frame->format = AV_SAMPLE_FMT_S16; frame->format = AV_SAMPLE_FMT_S16;
frame->channel_layout = c->channel_layout; frame->channel_layout = c->channel_layout;
ret = av_frame_get_buffer(frame, 0); ret = av_frame_get_buffer(frame, 0);
@ -167,13 +165,13 @@ static void write_audio_frame(AVFormatContext *oc, AVStream *st)
exit(1); exit(1);
} }
get_audio_frame(frame, c->channels); get_audio_frame(ost, frame, c->channels);
avcodec_encode_audio2(c, &pkt, frame, &got_packet); avcodec_encode_audio2(c, &pkt, frame, &got_packet);
if (!got_packet) if (!got_packet)
return; return;
pkt.stream_index = st->index; pkt.stream_index = ost->st->index;
/* Write the compressed frame to the media file. */ /* Write the compressed frame to the media file. */
if (av_interleaved_write_frame(oc, &pkt) != 0) { if (av_interleaved_write_frame(oc, &pkt) != 0) {
@ -183,9 +181,9 @@ static void write_audio_frame(AVFormatContext *oc, AVStream *st)
av_frame_free(&frame); av_frame_free(&frame);
} }
static void close_audio(AVFormatContext *oc, AVStream *st) static void close_audio(AVFormatContext *oc, OutputStream *ost)
{ {
avcodec_close(st->codec); avcodec_close(ost->st->codec);
} }
/**************************************************************/ /**************************************************************/
@ -413,13 +411,12 @@ static void close_video(AVFormatContext *oc, OutputStream *ost)
int main(int argc, char **argv) int main(int argc, char **argv)
{ {
OutputStream video_st; OutputStream video_st, audio_st;
const char *filename; const char *filename;
AVOutputFormat *fmt; AVOutputFormat *fmt;
AVFormatContext *oc; AVFormatContext *oc;
AVStream *audio_st;
double audio_pts, video_pts; double audio_pts, video_pts;
int have_video = 0; int have_video = 0, have_audio = 0;
int i; int i;
/* Initialize libavcodec, and register all codecs and formats. */ /* Initialize libavcodec, and register all codecs and formats. */
@ -458,21 +455,21 @@ int main(int argc, char **argv)
/* Add the audio and video streams using the default format codecs /* Add the audio and video streams using the default format codecs
* and initialize the codecs. */ * and initialize the codecs. */
audio_st = NULL;
if (fmt->video_codec != AV_CODEC_ID_NONE) { if (fmt->video_codec != AV_CODEC_ID_NONE) {
add_video_stream(&video_st, oc, fmt->video_codec); add_video_stream(&video_st, oc, fmt->video_codec);
have_video = 1; have_video = 1;
} }
if (fmt->audio_codec != AV_CODEC_ID_NONE) { if (fmt->audio_codec != AV_CODEC_ID_NONE) {
audio_st = add_audio_stream(oc, fmt->audio_codec); add_audio_stream(&audio_st, oc, fmt->audio_codec);
have_audio = 1;
} }
/* Now that all the parameters are set, we can open the audio and /* Now that all the parameters are set, we can open the audio and
* video codecs and allocate the necessary encode buffers. */ * video codecs and allocate the necessary encode buffers. */
if (have_video) if (have_video)
open_video(oc, &video_st); open_video(oc, &video_st);
if (audio_st) if (have_audio)
open_audio(oc, audio_st); open_audio(oc, &audio_st);
av_dump_format(oc, 0, filename, 1); av_dump_format(oc, 0, filename, 1);
@ -489,8 +486,8 @@ int main(int argc, char **argv)
for (;;) { for (;;) {
/* Compute current audio and video time. */ /* Compute current audio and video time. */
if (audio_st) if (have_audio)
audio_pts = (double)audio_st->pts.val * audio_st->time_base.num / audio_st->time_base.den; audio_pts = (double)audio_st.st->pts.val * audio_st.st->time_base.num / audio_st.st->time_base.den;
else else
audio_pts = 0.0; audio_pts = 0.0;
@ -500,13 +497,13 @@ int main(int argc, char **argv)
else else
video_pts = 0.0; video_pts = 0.0;
if ((!audio_st || audio_pts >= STREAM_DURATION) && if ((!have_audio || audio_pts >= STREAM_DURATION) &&
(!have_video || video_pts >= STREAM_DURATION)) (!have_video || video_pts >= STREAM_DURATION))
break; break;
/* write interleaved audio and video frames */ /* write interleaved audio and video frames */
if (!have_video || (have_video && audio_st && audio_pts < video_pts)) { if (!have_video || (have_video && have_audio && audio_pts < video_pts)) {
write_audio_frame(oc, audio_st); write_audio_frame(oc, &audio_st);
} else { } else {
write_video_frame(oc, &video_st); write_video_frame(oc, &video_st);
} }
@ -521,8 +518,8 @@ int main(int argc, char **argv)
/* Close each codec. */ /* Close each codec. */
if (have_video) if (have_video)
close_video(oc, &video_st); close_video(oc, &video_st);
if (audio_st) if (have_audio)
close_audio(oc, audio_st); close_audio(oc, &audio_st);
/* Free the streams. */ /* Free the streams. */
for (i = 0; i < oc->nb_streams; i++) { for (i = 0; i < oc->nb_streams; i++) {