RTP server for audio stream - c++

I'm in the mid of my project where I'm trying to send the audio data over RTP using ffmpeg in VC++.
but I'm unable to do that.
My start up code is:
setRTPOutputAddr("127.0.0.1");
setRTPOutputPort(9985);
av_register_all();
avformat_network_init();
formatCtx= avformat_alloc_context();
//av_dump_format(formatCtx,0,"rtp",1);
avio_open_dyn_buf(&ioctx);
avio_open(&formatCtx->pb, "rtp", AVIO_FLAG_WRITE);
//av_dump_format(formatCtx,0,"rtp",1);
formatCtx->pb = ioctx;
rtpCtx = avformat_alloc_context();
rtpCtx->oformat = av_guess_format("rtp",0,0);
AVStream *fakeVideo = 0;
fakeVideo = avformat_new_stream(rtpCtx,0);
avcodec_get_context_defaults3(fakeVideo->codec, NULL);
fakeVideo->codec->codec_id = AV_CODEC_ID_MPEG2TS;
rtpCtx->audio_codec_id = AV_CODEC_ID_NONE;
rtpCtx->video_codec_id = AV_CODEC_ID_MPEG2TS;
// avformat_write_header(rtpCtx,0);
char *url = new char[1024];
sprintf(url,"rtp://%s:%d",rtpOutputAddr,rtpOutputPort);
printf("will output to url:%s\n",url);
avio_open(&rtpCtx->pb,url,AVIO_FLAG_WRITE);
avformat_write_header(rtpCtx, NULL);
delete url;
if (avio_open(&formatCtx->pb, "rtp", AVIO_FLAG_WRITE) < 0)
{
fprintf(stderr, "Could not open '%s'\n", formatCtx->filename);
return -1;
}
else
{
printf("succeed \n");
}
Error Here: avformat_write_header(formatCtx, NULL); //program Crashes
Do anyone having any idea where I'm doing wrong?
Thanks!

Related

Get video from webcam using FFmpeg Libav

I am trying to record webcam video using FFmpeg C libraries (libav), on a Mac computer. I made changes to the transcode.c example so that it opens a device instead of a file. However, for some reason the code only receives a single packet and then closes.
static int open_input_source(const char *dev_name) {
int ret;
unsigned int i;
AVDictionary *p_av_options = NULL;
AVInputFormat *p_av_input_format = av_find_input_format("avfoundation");
av_dict_set(&p_av_options, "framerate", "30", 0);
ifmt_ctx = NULL;
if ((ret = avformat_open_input(&ifmt_ctx, dev_name, p_av_input_format, &p_av_options) < 0)) {
av_log(NULL, AV_LOG_ERROR, "Cannot open input file\n");
return ret;
}
if ((ret = avformat_find_stream_info(ifmt_ctx, NULL)) < 0) {
av_log(NULL, AV_LOG_ERROR, "Cannot find stream information\n");
return ret;
}
stream_ctx = av_calloc(ifmt_ctx->nb_streams, sizeof(*stream_ctx));
if (!stream_ctx)
return AVERROR(ENOMEM);
for (i = 0; i < ifmt_ctx->nb_streams; i++) {
AVStream *stream = ifmt_ctx->streams[i];
const AVCodec *dec = avcodec_find_decoder(stream->codecpar->codec_id);
AVCodecContext *codec_ctx;
if (!dec) {
av_log(NULL, AV_LOG_ERROR, "Failed to find decoder for stream #%u\n", i);
return AVERROR_DECODER_NOT_FOUND;
}
codec_ctx = avcodec_alloc_context3(dec);
if (!codec_ctx) {
av_log(NULL, AV_LOG_ERROR, "Failed to allocate the decoder context for stream #%u\n", i);
return AVERROR(ENOMEM);
}
ret = avcodec_parameters_to_context(codec_ctx, stream->codecpar);
if (ret < 0) {
av_log(NULL, AV_LOG_ERROR, "Failed to copy decoder parameters to input decoder context "
"for stream #%u\n", i);
return ret;
}
/* Reencode video & audio and remux subtitles etc. */
if (codec_ctx->codec_type == AVMEDIA_TYPE_VIDEO
|| codec_ctx->codec_type == AVMEDIA_TYPE_AUDIO) {
if (codec_ctx->codec_type == AVMEDIA_TYPE_VIDEO)
codec_ctx->framerate = av_guess_frame_rate(ifmt_ctx, stream, NULL);
/* Open decoder */
ret = avcodec_open2(codec_ctx, dec, NULL);
if (ret < 0) {
av_log(NULL, AV_LOG_ERROR, "Failed to open decoder for stream #%u\n", i);
return ret;
}
}
stream_ctx[i].dec_ctx = codec_ctx;
stream_ctx[i].dec_frame = av_frame_alloc();
if (!stream_ctx[i].dec_frame)
return AVERROR(ENOMEM);
}
av_dump_format(ifmt_ctx, 0, dev_name, 0);
return 0;
}
I have looked for other code examples but they are all deprecated and no longer compile in updated FFmpeg.
Is there some missing setting in my open_input_source function? Alternatively, is the problem in using transcoding is my basis? Should I try to use some other example?
In general, is there is a C source code reference which fulfills my requirements?
Thanks
This is a pretty fleshed out example that might meet your requirements:
https://github.com/argvk/ffmpeg-examples/blob/master/dshow_capture_video.c
I don't think you need nearly as much code as is include there, but you might be able to just update lines 260 with how long you want it to run (that example is 300 frames) and line 83 to open your webcam (sounds like you've already successfully done this with ret = avformat_open_input(&ifmt_ctx, dev_name, p_av_input_format, &p_av_options) in your code.
There are lots of other options there which you might want to remove, keep, or change depending on the details which are not provided here. Unfortunately I don't have a simplified code sample I'm able to share on here, but this dshow example is doing everything I expect.
Hope it helps some.

FFMPEG using AV_PIX_FMT_D3D11 gives "Error registering the input resource" from NVENC

Input frames start on the GPU as ID3D11Texture2D pointers.
I encode them to H264 using FFMPEG + NVENC. NVENC works perfectly if I download the textures to CPU memory as format AV_PIX_FMT_BGR0, but I'd like to cut out the CPU texture download entirely, and pass the GPU memory pointer directly into the encoder in native format. I write frames like this:
int write_gpu_video_frame(ID3D11Texture2D* gpuTex, AVFormatContext* oc, OutputStream* ost) {
AVFrame *hw_frame = ost->hw_frame;
printf("gpuTex address = 0x%x\n", &gpuTex);
hw_frame->data[0] = (uint8_t *) gpuTex;
hw_frame->data[1] = (uint8_t *) (intptr_t) 0;
hw_frame->pts = ost->next_pts++;
return write_frame(oc, ost->enc, ost->st, hw_frame);
// write_frame is identical to sample code in ffmpeg repo
}
Running the code with this modification gives the following error:
gpuTex address = 0x4582f6d0
[h264_nvenc # 00000191233e1bc0] Error registering an input resource: invalid call (9):
[h264_nvenc # 00000191233e1bc0] Could not register an input HW frame
Error sending a frame to the encoder: Unknown error occurred
Here's some supplemental code used in setting up and configuring the hw context and encoder:
/* A few config flags */
#define ENABLE_NVENC TRUE
#define USE_D3D11 TRUE // Skip downloading textures to CPU memory and send it straight to NVENC
/* Init hardware frame context */
static int set_hwframe_ctx(AVCodecContext* ctx, AVBufferRef* hw_device_ctx) {
AVBufferRef* hw_frames_ref;
AVHWFramesContext* frames_ctx = NULL;
int err = 0;
if (!(hw_frames_ref = av_hwframe_ctx_alloc(hw_device_ctx))) {
fprintf(stderr, "Failed to create HW frame context.\n");
throw;
}
frames_ctx = (AVHWFramesContext*) (hw_frames_ref->data);
frames_ctx->format = AV_PIX_FMT_D3D11;
frames_ctx->sw_format = AV_PIX_FMT_NV12;
frames_ctx->width = STREAM_WIDTH;
frames_ctx->height = STREAM_HEIGHT;
//frames_ctx->initial_pool_size = 20;
if ((err = av_hwframe_ctx_init(hw_frames_ref)) < 0) {
fprintf(stderr, "Failed to initialize hw frame context. Error code: %s\n", av_err2str(err));
av_buffer_unref(&hw_frames_ref);
throw;
}
ctx->hw_frames_ctx = av_buffer_ref(hw_frames_ref);
if (!ctx->hw_frames_ctx)
err = AVERROR(ENOMEM);
av_buffer_unref(&hw_frames_ref);
return err;
}
/* Add an output stream. */
static void add_video_stream(
OutputStream* ost,
AVFormatContext* oc,
const AVCodec** codec,
enum AVCodecID codec_id,
int width,
int height
) {
AVCodecContext* c;
int i;
bool nvenc = false;
/* find the encoder */
if (ENABLE_NVENC) {
printf("Getting nvenc encoder\n");
*codec = avcodec_find_encoder_by_name("h264_nvenc");
nvenc = true;
}
if (!ENABLE_NVENC || *codec == NULL) {
printf("Getting standard encoder\n");
avcodec_find_encoder(codec_id);
nvenc = false;
}
if (!(*codec)) {
fprintf(stderr, "Could not find encoder for '%s'\n",
avcodec_get_name(codec_id));
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;
printf("Using video codec %s\n", avcodec_get_name(codec_id));
c->codec_id = codec_id;
c->bit_rate = 4000000;
/* Resolution must be a multiple of two. */
c->width = STREAM_WIDTH;
c->height = STREAM_HEIGHT;
/* 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 = {1, STREAM_FRAME_RATE};
c->time_base = ost->st->time_base;
c->gop_size = 12; /* emit one intra frame every twelve frames at most */
if (nvenc && USE_D3D11) {
const std::string hw_device_name = "d3d11va";
AVHWDeviceType device_type = av_hwdevice_find_type_by_name(hw_device_name.c_str());
// set up hw device context
AVBufferRef *hw_device_ctx;
// const char* device = "0"; // Default GPU (may be integrated in the case of switchable graphics!)
const char* device = "1";
ret = av_hwdevice_ctx_create(&hw_device_ctx, device_type, device, nullptr, 0);
if (ret < 0) {
fprintf(stderr, "Could not create hwdevice context; %s", av_err2str(ret));
}
set_hwframe_ctx(c, hw_device_ctx);
c->pix_fmt = AV_PIX_FMT_D3D11;
} else if (nvenc && !USE_D3D11)
c->pix_fmt = AV_PIX_FMT_BGR0;
else
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;
}
/* Some formats want stream headers to be separate. */
if (oc->oformat->flags & AVFMT_GLOBALHEADER)
c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
}

av_read_frame of ffmpeg in windows always returning random packet.stream_index

I'm using ffmpeg to decode an rtsp stream, the av_read_frame is always returning random value on packet.stream_index.
The stream have only 2 index, 1 video and 1 audio respectively on streams[0] and streams[1].
But when i call av_read_frame, i've random value on packet.stream_index and no data in the packet.
If someone can help me, i'm beginner in FFMPEG.
I add my simplified code to make you an idea of what i do :
AVFormatContext* input_ctx = NULL;
AVStream* video_st = NULL;
AVCodecContext* decoder_ctx = NULL;
AVCodec* decoder;
AVPacket pkt = { 0 };
AVFrame* frame = NULL;
DWORD dwHeight = 576;
DWORD dwWidth = 704;
int ret, i;
input_ctx = avformat_alloc_context();
/* open the input file */
ret = avformat_open_input(&input_ctx, "rtsp://**************************/Streaming/Channels/102?profile=Profile_1", NULL, NULL);
avformat_find_stream_info(input_ctx, NULL);
av_dump_format(input_ctx, 0, "rtsp://**************************/Streaming/Channels/102?profile=Profile_1", 0);
av_find_best_stream(input_ctx, AVMEDIA_TYPE_VIDEO, 0, -1, &decoder, 0);
/* find the first H.264 video stream */
for (i = 0; i < input_ctx->nb_streams-1; i++) {
AVStream *st = input_ctx->streams[i];
video_st = st;
}
decoder_ctx = input_ctx->streams[0]->codec;
decoder = avcodec_find_decoder(decoder_ctx->codec_id);
decoder_ctx = avcodec_alloc_context3(decoder);
ret = avcodec_open2(decoder_ctx, NULL, NULL);
frame = av_frame_alloc();
av_read_play(input_ctx);
/* actual decoding */
while (ret >= 0) {
ret = av_read_frame(input_ctx, &pkt);
if (pkt.stream_index == video_st->index) {
if ((avcodec_send_packet != NULL)&&(avcodec_receive_frame!=NULL)) {
ret = avcodec_send_packet(decoder_ctx, pkt);
Thx in advance.

ffmpeg memory leak in the avcodec_open2 method

I've developed an application which handles live video stream. The problem is that it should run as a service and over time I am noticing some memory increase. When I check the application with valgrind - it did not find any leak related issues.
So I've check it with google profile tools. This is a result(substracting the one of the first dumps from the latest) after approximately 6 hour run:
30.0 35.7% 35.7% 30.0 35.7% av_malloc
28.9 34.4% 70.2% 28.9 34.4% av_reallocp
24.5 29.2% 99.4% 24.5 29.2% x264_malloc
When I check the memory on the graph I see, that these allocations are related to avcodec_open2. The client code is:
` g_EncoderMutex.lock();
ffmpeg_encoder_start(OutFileName.c_str(), AV_CODEC_ID_H264, m_FPS, width, height);
for (pts = 0; pts < VideoImages.size(); pts++) {
m_frame->pts = pts;
ffmpeg_encoder_encode_frame(VideoImages[pts].RGBimage[0]);
}
ffmpeg_encoder_finish();
g_EncoderMutex.unlock()
The ffmpeg_encoder_start method is:
void VideoEncoder::ffmpeg_encoder_start(const char *filename, int codec_id, int fps, int width, int height)
{
int ret;
m_FPS=fps;
AVOutputFormat * fmt = av_guess_format(filename, NULL, NULL);
m_oc = NULL;
avformat_alloc_output_context2(&m_oc, NULL, NULL, filename);
m_stream = avformat_new_stream(m_oc, 0);
AVCodec *codec=NULL;
codec = avcodec_find_encoder(codec_id);
if (!codec)
{
fprintf(stderr, "Codec not found\n");
return; //-1
}
m_c=m_stream->codec;
avcodec_get_context_defaults3(m_c, codec);
m_c->bit_rate = 400000;
m_c->width = width;
m_c->height = height;
m_c->time_base.num = 1;
m_c->time_base.den = m_FPS;
m_c->gop_size = 10;
m_c->max_b_frames = 1;
m_c->pix_fmt = AV_PIX_FMT_YUV420P;
if (codec_id == AV_CODEC_ID_H264)
av_opt_set(m_c->priv_data, "preset", "ultrafast", 0);
if (m_oc->oformat->flags & AVFMT_GLOBALHEADER)
m_c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
avcodec_open2( m_c, codec, NULL );
m_stream->time_base=(AVRational){1, m_FPS};
if (avio_open(&m_oc->pb, filename, AVIO_FLAG_WRITE) < 0)
{
printf( "Could not open '%s'\n", filename);
exit(1);
}
avformat_write_header(m_oc, NULL);
m_frame = av_frame_alloc();
if (!m_frame) {
printf( "Could not allocate video frame\n");
exit(1);
}
m_frame->format = m_c->pix_fmt;
m_frame->width = m_c->width;
m_frame->height = m_c->height;
ret = av_image_alloc(m_frame->data, m_frame->linesize, m_c->width, m_c->height, m_c->pix_fmt, 32);
if (ret < 0) {
printf("Could not allocate raw picture buffer\n");
exit(1);
}
}
The ffmpeg_encoder_encode_frame is:
void VideoEncoder::ffmpeg_encoder_encode_frame(uint8_t *rgb)
{
int ret, got_output;
ffmpeg_encoder_set_frame_yuv_from_rgb(rgb);
av_init_packet(&m_pkt);
m_pkt.data = NULL;
m_pkt.size = 0;
ret = avcodec_encode_video2(m_c, &m_pkt, m_frame, &got_output);
if (ret < 0) {
printf("Error encoding frame\n");
exit(1);
}
if (got_output)
{
av_packet_rescale_ts(&m_pkt,
(AVRational){1, m_FPS}, m_stream->time_base);
m_pkt.stream_index = m_stream->index;
int ret = av_interleaved_write_frame(m_oc, &m_pkt);
av_packet_unref(&m_pkt);
}
}
ffmpeg_encoder_finish code is:
void VideoEncoder::ffmpeg_encoder_finish(void)
{
int got_output, ret;
do {
ret = avcodec_encode_video2(m_c, &m_pkt, NULL, &got_output);
if (ret < 0) {
printf( "Error encoding frame\n");
exit(1);
}
if (got_output) {
av_packet_rescale_ts(&m_pkt,
(AVRational){1, m_FPS}, m_stream->time_base);
m_pkt.stream_index = m_stream->index;
int ret = av_interleaved_write_frame(m_oc, &m_pkt);
av_packet_unref(&m_pkt);
}
} while (got_output);
av_write_trailer(m_oc);
avio_closep(&m_oc->pb);
avformat_free_context(m_oc);
av_freep(&m_frame->data[0]);
av_frame_free(&m_frame);
av_packet_unref(&m_pkt);
sws_freeContext(m_sws_context);
}
This code runs multiple times in the loop.
So my question is - what am I doing wrong? maybe ffmpeg is using some kind of internal buffering? If so, how to disable it? Because such an increase in memory usage is unacceptable at all.
You didn't close encoder context. Add avcodec_close(m_c) to ffmpeg_encoder_finish().
See ffmpeg.org
User is required to call avcodec_close() and avformat_free_context() to clean up the allocation by avformat_new_stream().
Plus I don't see how m_c is allocated. Usually it is allocated with avcodec_alloc_context and must be deallocated with av_free (after closing of course).
Don't use valgrind to check memory leaks for your own projects, use sanitizers, with these you can pin point the source of the leak. Check this out: Multi-Threaded Video Decoder Leaks Memory
Hope that helps.
It's sufficient to call 'avcodec_free_context(m_c)', this procedure calls 'avcodec_close' and also de-allocates 'extradata'(if it's was allocated) and 'subtitle_header' (if it was allocated).

Audio/Video encoding with ffmpeg

Audio/Video encoding with ffmpeg:
I am trying to create an avi file with encoded video and audio, using ffmpeg.
First, I create the file:
//define BITRATE 10000000
//define GOP 300
//define FPS 60
//define VIDEOTYPE "avi"
if (!encoder_->createFile(QFileInfo(*(videoFile_.data())).absoluteFilePath(), targetRect.width(), targetRect.height(), BITRATE*(1000 / FPS), GOP, 1000))
The buffers are initialized as:
audio_outbuf_size = 44100 * 0.005 * 16; //5ms of audio should be encoded, each time this function is called
audio_outbuf = new uint8_t[audio_outbuf_size];
outbuf_size = getWidth()*getHeight() * 3;
outbuf = new uint8_t[outbuf_size];
Then add audio and video streams (audio: CODEC_ID_PCM_S16LE, 16000 kb/s and 44100 Hz, video: PIX_FMT_YUV420P)
void MediaMuxer::addAudioStream(QString fileName, ffmpeg::CodecID codec_id)
{
// Add the audio stream
ffmpeg::AVCodec *encoder = avcodec_find_encoder(codec_id);
pAudioStream_ = ffmpeg::av_new_stream(pOutputFormatCtx_, 0);
if (!pAudioStream_) {
printf("Could not allocate stream\n");
return;
}
pAudioCodecCtx_ = pAudioStream_->codec;
pAudioCodecCtx_->codec_id = codec_id;
pAudioCodecCtx_->codec_type = ffmpeg::AVMEDIA_TYPE_AUDIO;
pAudioCodecCtx_->sample_fmt = ffmpeg::AV_SAMPLE_FMT_S16;
pAudioCodecCtx_->sample_fmt = encoder->sample_fmts[0];
pAudioCodecCtx_->bit_rate = 16000;
//pAudioCodecCtx_->bit_rate = 64000;
pAudioCodecCtx_->sample_rate = N;
pAudioCodecCtx_->channels = 1;
pAudioCodecCtx_->time_base.den = FPS;
pAudioCodecCtx_->time_base.num = 1;
avcodec_thread_init(pAudioCodecCtx_, 10);
// some formats want stream headers to be separate
if (pOutputFormatCtx_->oformat->flags & AVFMT_GLOBALHEADER)
pAudioCodecCtx_->flags |= CODEC_FLAG_GLOBAL_HEADER;
if (av_set_parameters(pOutputFormatCtx_, NULL) < 0)
{
printf("Invalid output format parameters\n");
return;
}
//ffmpeg::dump_format(pOutputFormatCtx_, 0, fileName.toStdString().c_str(), 1);
// open_video
// find the audio encoder
pAudioCodec_ = avcodec_find_encoder(pAudioCodecCtx_->codec_id);
if (!pAudioCodec_)
{
printf("codec not found\n");
return;
}
// open the codec
if (avcodec_open(pAudioCodecCtx_, pAudioCodec_) < 0)
{
printf("could not open codec\n");
return;
}
// Allocate memory for output
if (!initAudioOutputBuf())
{
printf("Can't allocate memory for audio output bitstream\n");
return;
}
// Allocate the audio frame
if (!initAudioFrame())
{
printf("Can't init audio frame\n");
return;
}
if (url_fopen(&pOutputFormatCtx_->pb, fileName.toStdString().c_str(), URL_WRONLY) < 0)
{
printf("Could not open '%s'\n", fileName.toStdString().c_str());
return;
}
av_write_header(pOutputFormatCtx_);
}
void MediaMuxer::addVideoStream(QString fileName)
{
// Add the video stream
pVideoStream_ = ffmpeg::av_new_stream(pOutputFormatCtx_, 0);
if (!pVideoStream_)
{
printf("Could not allocate stream\n");
return;
}
pVideoCodecCtx_ = pVideoStream_->codec;
pVideoCodecCtx_->codec_id = pOutputFormat_->video_codec;
pVideoCodecCtx_->codec_type = ffmpeg::AVMEDIA_TYPE_VIDEO;
pVideoCodecCtx_->bit_rate = Bitrate;
pVideoCodecCtx_->width = getWidth();
pVideoCodecCtx_->height = getHeight();
pVideoCodecCtx_->time_base.den = FPS;
pVideoCodecCtx_->time_base.num = 1;
pVideoCodecCtx_->gop_size = Gop;
pVideoCodecCtx_->pix_fmt = ffmpeg::PIX_FMT_YUV420P;
avcodec_thread_init(pVideoCodecCtx_, 10);
// some formats want stream headers to be separate
if (pOutputFormatCtx_->oformat->flags & AVFMT_GLOBALHEADER)
pVideoCodecCtx_->flags |= CODEC_FLAG_GLOBAL_HEADER;
if (av_set_parameters(pOutputFormatCtx_, NULL) < 0)
{
printf("Invalid output format parameters\n");
return;
}
//ffmpeg::dump_format(pOutputFormatCtx_, 0, fileName.toStdString().c_str(), 1);
// open_video
// find the video encoder
pVideoCodec_ = avcodec_find_encoder(pVideoCodecCtx_->codec_id);
if (!pVideoCodec_)
{
printf("codec not found\n");
return;
}
// open the codec
if (avcodec_open(pVideoCodecCtx_, pVideoCodec_) < 0)
{
printf("could not open codec\n");
return;
}
// Allocate memory for output
if (!initOutputBuf())
{
printf("Can't allocate memory for output bitstream\n");
return;
}
// Allocate the YUV frame
if (!initFrame())
{
printf("Can't init frame\n");
return;
}
if (url_fopen(&pOutputFormatCtx_->pb, fileName.toStdString().c_str(), URL_WRONLY) < 0)
{
printf("Could not open '%s'\n", fileName.toStdString().c_str());
return;
}
av_write_header(pOutputFormatCtx_);
}
Finally, I call alternatively encodeVideo/encodeAudio to encode video and PCM audio frames at specific recording times(pts):
int MediaMuxer::encodeVideo(const QImage &img, unsigned pts)
{
convertImage_sws(img); // SWS conversion
pVideoCodecCtx_->coded_frame->pts = pts; // Set the time stamp
int out_size = ffmpeg::avcodec_encode_video(pVideoCodecCtx_, outbuf, outbuf_size, ppicture);
pVideoCodecCtx_->coded_frame->pts = pts; // Set the time stamp
if (out_size > 0)
{
ffmpeg::av_init_packet(&pkt);
if (pVideoCodecCtx_->coded_frame->pts != (0x8000000000000000LL))
pkt.pts = av_rescale_q(pVideoCodecCtx_->coded_frame->pts, pVideoCodecCtx_->time_base, pVideoStream_->time_base);
if (pVideoCodecCtx_->coded_frame->key_frame)
pkt.flags |= AV_PKT_FLAG_KEY;
pkt.stream_index = pVideoStream_->index;
pkt.data = outbuf;
pkt.size = out_size;
int ret = ffmpeg::av_interleaved_write_frame(pOutputFormatCtx_, &pkt);
if (ret<0)
return -1;
}
return out_size;
}
int MediaMuxer::encodeAudio(unsigned pts)
{
pAudioCodecCtx_->coded_frame->pts = pts; // Set the time stamp
// simple sound encoding
int16_t samples[220] = { 0 }; // buffer
int n; // buffer index
double Fs = 44100.0; // sampling frequency
// Generate audio data
for (n = 0; n < 220; ++n) //220 samples (44100*.005sec as the interval between 2 video frames is 10ms)
samples[n] = 16383.0 * sin(n*1000.0*2.0*M_PI / Fs); //sine wav
int out_size = ffmpeg::avcodec_encode_audio(pAudioCodecCtx_, audio_outbuf, audio_outbuf_size, (const short*)samples);
pAudioCodecCtx_->coded_frame->pts = pts; // Set the time stamp
if (out_size>0)
{
// Packet
ffmpeg::AVPacket pkt = { 0 };
av_init_packet(&pkt);
pkt.data = NULL; // packet data will be allocated by the encoder
pkt.size = 0;
if (pAudioCodecCtx_->coded_frame->pts != (0x8000000000000000LL))
pkt.pts = av_rescale_q(pAudioCodecCtx_->coded_frame->pts, pAudioCodecCtx_->time_base, pAudioStream_->time_base);
if (pAudioCodecCtx_->coded_frame->key_frame)
pkt.flags |= AV_PKT_FLAG_KEY;
pkt.stream_index = pAudioStream_->index;
pkt.data = audio_outbuf;
pkt.size = out_size;
int ret = av_interleaved_write_frame(pOutputFormatCtx_, &pkt);
if (ret<0)
return -1;
av_free_packet(&pkt);
}
//end simple sound encoding
return pkt.size;
}
The result is a nice video with some audio behind (either a regular beeping sound at regular intervals but ending way earlier than the video or a continuous longer sound that also last shorter than the video).
I want to generate a beeping sound each time the function encodeAudio() is called - at non-regular intervals. I have tried to modify the sampling rate, the buffer size, the pkt size and the number of samples but without any success. I also tried to set the pts at different times but it did not get me where I want to be. Could someone please help?