我从偶数驱动源接收原始h264和aac音频帧。我试图将这些帧发送到rtmp服务器。 我开始使用ffmpeg示例muxing.c，它成功地将自定义流发送到rtmp服务器。我想我只需要用自己的框架数据替换他们的框架数据。我在网上找到了这个建议。我试过How to pack raw h264 stream to flv container and send over rtmp using ffmpeg (not command) 和 How to publish selfmade stream with ffmpeg and c++ to rtmp server? 和其他一些建议，但没有一个对我有用。 我试图直接memcpy我的字节缓冲区，但我的代码一直失败 at ret = avcodec_encode_video2（c，＆amp; pkt，frame，＆amp; got_packet）。 具体来说，我得到一个无效的访问错误。 对于更多上下文，无论何时我收到一个帧（由事件驱动），都会调用void RTMPWriter :: WriteVideoFrame（...）。假设在收到第一帧之前已经调用了构造函数。 我对ffmpeg并不熟悉，代码可能有几个问题。任何输入都将非常感激。
#define STREAM_FRAME_RATE 25 /* 25 images/s */
#define STREAM_PIX_FMT AV_PIX_FMT_YUV420P /* default pix_fmt */
#define SCALE_FLAGS SWS_BICUBIC
RTMPWriter::RTMPWriter()
: seenKeyFrame(false),
video_st({ 0 }),
audio_st({ 0 }),
have_video(0),
have_audio(0)
{
const char *filename;
AVCodec *audio_codec = NULL, *video_codec = NULL;
int ret;
int encode_video = 0, encode_audio = 0;
AVDictionary *opt = NULL;
int i;
/* Initialize libavcodec, and register all codecs and formats. */
av_register_all();
avformat_network_init();
String^ StreamURL = "StreamURL";
String^ out_uri = safe_cast<Platform::String^>(ApplicationData::Current->LocalSettings->Values->Lookup(StreamURL));
std::wstring out_uriW(out_uri->Begin());
std::string out_uriA(out_uriW.begin(), out_uriW.end());
filename = out_uriA.c_str();
/* allocate the output media context */
avformat_alloc_output_context2(&oc, NULL, "flv", filename);
if (!oc)
{
OutputDebugString(L"Could not deduce output format from file extension: using MPEG.\n");
avformat_alloc_output_context2(&oc, NULL, "mpeg", filename);
}
if (!oc)
{
OutputDebugString(L"Could not allocate using MPEG.\n");
}
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)
{
OutputDebugString(L"Could not open ");
OutputDebugString(out_uri->Data());
}
}
/* Write the stream header, if any. */
ret = avformat_write_header(oc, &opt);
if (ret < 0)
{
OutputDebugString(L"Error occurred when writing stream header \n");
}
}
void RTMPWriter::WriteVideoFrame(
boolean isKeyFrame,
boolean hasDiscontinuity,
UINT64 frameId,
UINT32 videoBufferLength,
BYTE *videoBytes)
{
int ret;
AVCodecContext *c;
AVFrame* frame;
int got_packet = 0;
AVPacket pkt = { 0 };
c = video_st.enc;
frame = get_video_frame(videoBufferLength, videoBytes);
/* encode the image */
ret = avcodec_encode_video2(c, &pkt, frame, &got_packet);
if (ret < 0) {
OutputDebugString(L"Error encoding video frame: \n")
}
if (got_packet)
{
ret = write_frame(oc, &c->time_base, video_st.st, &pkt);
}
else {
ret = 0;
}
if (ret < 0) {
OutputDebugString(L"Error while writing video frame: %s\n");
}
}
AVFrame * RTMPWriter::get_video_frame(
UINT32 videoBufferLength,
BYTE *videoBytes)
{
AVCodecContext *c = video_st.enc;
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 (!video_st.sws_ctx) {
video_st.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 (!video_st.sws_ctx) {
fprintf(stderr,
"Could not initialize the conversion context\n");
exit(1);
}
}
fill_yuv_image(video_st.tmp_frame, video_st.next_pts, c->width, c->height, videoBufferLength, videoBytes);
sws_scale(video_st.sws_ctx,
(const uint8_t * const *)video_st.tmp_frame->data, video_st.tmp_frame->linesize,
0, c->height, video_st.frame->data, video_st.frame->linesize);
}
else {
fill_yuv_image(video_st.frame, video_st.next_pts, c->width, c->height, videoBufferLength, videoBytes);
}
video_st.frame->pts = video_st.next_pts++;
return video_st.frame;
}
/* Prepare a dummy image. */
void RTMPWriter::fill_yuv_image(
AVFrame *pict,
int frame_index,
int width,
int height,
UINT32 videoBufferLength,
BYTE *videoBytes)
{
//int x, y, i, ret;
/* 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(pict);
if (ret < 0)
{
OutputDebugString(L"Unable to make piture writable");
}
memcpy(pict->data, videoBytes, videoBufferLength);
//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;
// }
//}
}
void RTMPWriter::WriteAudioFrame()
{
}
/* Add an output stream. */
void RTMPWriter::add_stream(
OutputStream *ost,
AVFormatContext *oc,
AVCodec **codec,
enum AVCodecID codec_id)
{
AVCodecContext *c;
int i;
/* find the encoder */
*codec = avcodec_find_encoder(codec_id);
if (!(*codec)) {
OutputDebugString(L"Could not find encoder for '%s'\n");
//avcodec_get_name(codec_id));
exit(1);
}
ost->st = avformat_new_stream(oc, NULL);
if (!ost->st) {
OutputDebugString(L"Could not allocate stream\n");
exit(1);
}
ost->st->id = oc->nb_streams - 1;
c = avcodec_alloc_context3(*codec);
if (!c) {
OutputDebugString(L"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;
}
}
c->channels = av_get_channel_layout_nb_channels(c->channel_layout);
c->channel_layout = AV_CH_LAYOUT_STEREO;
if ((*codec)->channel_layouts) {
c->channel_layout = (*codec)->channel_layouts[0];
for (i = 0; (*codec)->channel_layouts[i]; i++) {
if ((*codec)->channel_layouts[i] == AV_CH_LAYOUT_STEREO)
c->channel_layout = AV_CH_LAYOUT_STEREO;
}
}
c->channels = av_get_channel_layout_nb_channels(c->channel_layout);
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;
}
AVFrame * RTMPWriter::alloc_audio_frame(
enum AVSampleFormat sample_fmt,
uint64_t channel_layout,
int sample_rate, int nb_samples)
{
AVFrame *frame = av_frame_alloc();
int ret;
if (!frame) {
OutputDebugString(L"Error allocating an audio frame\n");
exit(1);
}
frame->format = sample_fmt;
frame->channel_layout = channel_layout;
frame->sample_rate = sample_rate;
frame->nb_samples = nb_samples;
if (nb_samples) {
ret = av_frame_get_buffer(frame, 0);
if (ret < 0) {
OutputDebugString(L"Error allocating an audio buffer\n");
exit(1);
}
}
return frame;
}
void RTMPWriter::open_audio(
AVFormatContext *oc,
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) {
OutputDebugString(L"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->channel_layout,
c->sample_rate, nb_samples);
ost->tmp_frame = alloc_audio_frame(AV_SAMPLE_FMT_S16, c->channel_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) {
OutputDebugString(L"Could not copy the stream parameters\n");
exit(1);
}
/* create resampler context */
ost->swr_ctx = swr_alloc();
if (!ost->swr_ctx) {
OutputDebugString(L"Could not allocate resampler context\n");
exit(1);
}
/* set options */
av_opt_set_int(ost->swr_ctx, "in_channel_count", c->channels, 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_int(ost->swr_ctx, "out_channel_count", c->channels, 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) {
OutputDebugString(L"Failed to initialize the resampling context\n");
exit(1);
}
}
int RTMPWriter::write_frame(
AVFormatContext *fmt_ctx,
const AVRational *time_base,
AVStream *st,
AVPacket *pkt)
{
/* rescale output packet timestamp values from codec to stream timebase */
av_packet_rescale_ts(pkt, *time_base, st->time_base);
pkt->stream_index = st->index;
/* Write the compressed frame to the media file. */
//log_packet(fmt_ctx, pkt);
OutputDebugString(L"Actually sending video frame: %s\n");
return av_interleaved_write_frame(fmt_ctx, pkt);
}
AVFrame *RTMPWriter::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, 32);
if (ret < 0) {
fprintf(stderr, "Could not allocate frame data.\n");
exit(1);
}
return picture;
}
void RTMPWriter::open_video(
AVFormatContext *oc,
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) {
OutputDebugString(L"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) {
OutputDebugString(L"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) {
OutputDebugString(L"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) {
OutputDebugString(L"Could not copy the stream parameters\n");
exit(1);
}
}
void RTMPWriter::close_stream(AVFormatContext *oc, OutputStream *ost)
{
avcodec_free_context(&ost->enc);
av_frame_free(&ost->frame);
av_frame_free(&ost->tmp_frame);
sws_freeContext(ost->sws_ctx);
swr_free(&ost->swr_ctx);
}
RTMPWriter::~RTMPWriter()
{
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);
}