Recherche avancée
Médias (1)
-
The Slip - Artworks
26 septembre 2011, par
Mis à jour : Septembre 2011
Langue : English
Type : Texte
Autres articles (95)
-
Les vidéos
21 avril 2011, parComme les documents de type "audio", Mediaspip affiche dans la mesure du possible les vidéos grâce à la balise html5 .
Un des inconvénients de cette balise est qu’elle n’est pas reconnue correctement par certains navigateurs (Internet Explorer pour ne pas le nommer) et que chaque navigateur ne gère en natif que certains formats de vidéos.
Son avantage principal quant à lui est de bénéficier de la prise en charge native de vidéos dans les navigateur et donc de se passer de l’utilisation de Flash et (...) -
Websites made with MediaSPIP
2 mai 2011, parThis page lists some websites based on MediaSPIP.
-
Possibilité de déploiement en ferme
12 avril 2011, parMediaSPIP peut être installé comme une ferme, avec un seul "noyau" hébergé sur un serveur dédié et utilisé par une multitude de sites différents.
Cela permet, par exemple : de pouvoir partager les frais de mise en œuvre entre plusieurs projets / individus ; de pouvoir déployer rapidement une multitude de sites uniques ; d’éviter d’avoir à mettre l’ensemble des créations dans un fourre-tout numérique comme c’est le cas pour les grandes plate-formes tout public disséminées sur le (...)
Sur d’autres sites (6711)
-
Subtitling Sierra VMD Files
1er juin 2016, par Multimedia Mike — Game HackingI was contacted by a game translation hobbyist from Spain (henceforth known as The Translator). He had set his sights on Sierra’s 7-CD Phantasmagoria. This mammoth game was driven by a lot of FMV files and animations that have speech. These require language translation in the form of video subtitling. He’s lucky that he found possibly the one person on the whole internet who has just the right combination of skill, time, and interest to pull this off. And why would I care about helping ? I guess I share a certain camaraderie with game hackers. Don’t act so surprised. You know what kind of stuff I like to work on.
The FMV format used in this game is VMD, which makes an appearance in numerous Sierra titles. FFmpeg already supports decoding this format. FFmpeg also supports subtitling video. So, ideally, all that’s necessary to support this goal is to add a muxer for the VMD format which can encode raw video and audio, which the format supports. Implement video compression as extra credit.
The pipeline that I envisioned looks like this :
VMD Subtitling Process
“Trivial !” I surmised. I just never learn, do I ?
The Plan
So here’s my initial pitch, outlining the work I estimated that I would need to do towards the stated goal :- Create a new file muxer that produces a syntactically valid VMD file with bogus video and audio data. Make sure it works with both FFmpeg’s playback system as well as the proper Phantasmagoria engine.
- Create a new video encoder that essentially operates in pass-through mode while correctly building a palette.
- Create a new basic encoder for the video frames.
A big unknown for me was exactly how subtitle handling operates in FFmpeg. Thanks to this project, I now know. I was concerned because I was pretty sure that font rendering entails anti-aliasing which bodes poorly for keeping the palette count under 256 unique colors.
Computer Science Puzzle
When pondering how to process the palette, I was excited for the opportunity to exercise actual computer science. FFmpeg converts frames from paletted frames to full RGB frames. Then it needs to convert them back to paletted frames. I had a vague recollection of solving this problem once before when I was experimenting with a new paletted video codec. I seem to recall that I did the palette conversion in a very naive manner. I just used a static 256-element array and processed each RGB pixel of the frame, seeing if the value already occurred in the table (O(n) lookup) and adding it otherwise.
There are more efficient algorithms, however, such as hash tables and trees. Somewhere along the line, FFmpeg helpfully acquired a rarely-used tree data structure, which was perfect for this project.
So I was pretty pleased with this optimization. Too bad this wouldn’t survive to the end of the effort.
Another palette-related challenge was the fact that a group of pictures would be accumulating a new palette but that palette needed to be recorded before the group. Thus, the muxer needed to have extra logic to rewind the file when the video encoder transmitted a palette change.
Video Compression
VMD has a few methods in its compression toolbox. It can use interframe differencing, it has some RLE, or it can code a frame raw. It can also use a custom LZ-like format on top of these. For early prototypes, I elected to leave each frame coded raw. After the concept was proved, I implemented the frame differencing.
Top frame compared with the middle frame yields the bottom frame : red pixels indicate changesEncoding only those red dots in between vast runs of unchanged pixels yielded a vast measurable improvement. The next step was to try wiring up FFmpeg’s existing LZ compression facilities to the encoder. This turned out to be implausible since VMD’s LZ variant has nothing to do with anything FFmpeg already provides. Fortunately, the LZ piece is not absolutely required and the frame differencing + RLE provides plenty of compression.
Subtitling
I’ve never done anything, multimedia programming-wise, concerning subtitles. I guess all the entertainment I care about has always been in my native tongue. What a good excuse to program outside of my comfort zone !First, I needed to know how to access FFmpeg’s subtitling facilities. Fortunately, The Translator did the legwork on this matter so I didn’t have to figure it out.
However, I intuitively had misgivings about this phase. I had heard that the subtitling process performs anti-aliasing. That means that the image would need to be promoted to a higher colorspace for this phase and that the anti-aliasing process would likely push the color count way past 256. Some quick tests revealed this to be the case, as the running color count would leap by several hundred colors as soon as the palette accounting algorithm encountered a subtitle.
So I dug into the subtitle subsystem. I discovered that the subtitle library operates by creating a linked list of subtitle bitmaps that the client app must render. The bitmaps are comprised of 8-bit alpha transparency values that must be composited onto the target frame (i.e., 0 = transparent, 255 = 100% opaque). For example, the letter ‘H’ :
(with 00s removed) 13 F8 41 00 00 00 00 68 E4 | 13 F8 41 68 E4 14 FF 44 00 00 00 00 6C EC | 14 FF 44 6C EC 14 FF 44 00 00 00 00 6C EC | 14 FF 44 6C EC 14 FF 44 00 00 00 00 6C EC | 14 FF 44 6C EC 14 FF DC D0 D0 D0 D0 E4 EC | 14 FF DC D0 D0 D0 D0 E4 EC 14 FF 7E 50 50 50 50 9A EC | 14 FF 7E 50 50 50 50 9A EC 14 FF 44 00 00 00 00 6C EC | 14 FF 44 6C EC 14 FF 44 00 00 00 00 6C EC | 14 FF 44 6C EC 14 FF 44 00 00 00 00 6C EC | 14 FF 44 6C EC 11 E0 3B 00 00 00 00 5E CE | 11 E0 3B 5E CETo get around the color explosion problem, I chose a threshold value and quantized values above and below to 255 and 0, respectively. Further, the process chooses an appropriate color from the existing palette rather than introducing any new colors.
Muxing Matters
In order to force VMD into a general purpose media framework, a lot of special information needs to be passed around. Like many paletted codecs, the palette needs to be transmitted from the file demuxer to the video decoder via some side channel. For re-encoding, this also implies that the palette needs to make the trip from the video encoder to the file muxer. As if this wasn’t enough, individual VMD frames have even more data that needs to be ferried between the muxer and codec levels, including frame change boundaries. FFmpeg provides methods to do these things, but I could not always rely on the systems to relay the data in all cases. I was probably doing something wrong ; I accept that. Instead, I just packed all the information at the front of an encoded frame and split it apart in the muxer.I could not quite figure out how to get the audio and video muxed correctly. As a result, neither FFmpeg nor the Phantasmagoria engine could replay the files correctly.
Plan B
Since I was having so much trouble creating an entirely new VMD file, likely due to numerous unknown bits of the file format, I thought of another angle : re-use the existing VMD file. For this approach, I kept the video encoder and file muxer that I created in the initial phase, but modified the file muxer to emit a special intermediate file. Then, I created a Python tool to repackage the original VMD file using compressed video data in the intermediate file.For this phase, I also implemented a command line switch for FFmpeg to disable subtitle blending, to make the feature feel like less of an unofficial hack, as though this nonsense would ever have a chance of being incorporated upstream.
At this point, I was seeing some success with the complete, albeit roundabout, subtitling process. I constructed a subtitle file using “Spanish I Learned From Mexican Telenovelas” and the frames turned out fairly readable :
“she cheated on him”
“he’s a scumbag” … these random subtitles could fit surprisingly well !
The few files that I tested appeared to work fine. But then I handed off my work to The Translator and he immediately found a bunch of problems. According to my notes, the problems mostly took the form of flashing, solid color frames. Further, I found tiny, mostly imperceptible flaws in my RLE compressor, usually only detectable by running strict comparison tools ; but I wasn’t satisfied.
At this point, I think I attempted to just encode the entire palette at the front of each frame, as allowed by the format, but that did not seem to fix any problems. My notes are not completely clear on this matter (likely because I was still trying to figure out the exact problem), but I think it had to do with FFmpeg inserting extra video frames in order to even out gaps in the video framerate.
Sigh, Plan C
At this point, I was getting tired of trying to force FFmpeg to do this. So I decided to minimize its involvement using lessons learned up to this point.The next pitch :
- Create a new C program that can open an existing VMD file and output an identical VMD file. I know this sounds easy, but the specific method of copying entails interpreting individual parts of the file and writing those individual parts to the new file. This is in preparation for…
- Import the VMD video decoder functions directly into the program to decode the individual video frames and re-encode them, replacing the video frames as the file is rewritten.
- Wire up the subtitle system. During the adventure to disable subtitle blending, I accidentally learned enough about interfacing to the subtitle library to just invoke it directly.
- Rewrite the RLE method so that it is 100% correct.
Off to work I went. That part about lifting the existing VMD decoder functions out of their libavcodec nest turned out to not be that straightforward. As an alternative, I modified the decoder to dump the raw frames to an intermediate file. In doing so, I think I was able to avoid the issue of the duplicated frames that plagued the previous efforts.
Also, remember how I was really pleased with the palette conversion technique in which I was able to leverage computer science big-O theory ? By this stage, I had no reason to convert the paletted video to RGB in the first place ; all of the decoding, subtitling and re-encoding operates in the paletted colorspace.
This approach seemed to work pretty well. The final program is subtitle-vmd.c. The process is still a little weird. The modifications in my own FFmpeg fork are necessary to create an intermediate file that the new C tool can operate with.
Next Steps
The Translator has found some assorted bugs and corner cases that still need to be ironed out. Further, for extra credit, I need find the change windows for each frame to improve compression just a little more. I don’t think I will be trying for LZ compression, though.However, almost as soon as I had this whole system working, The Translator informed me that there is another, different movie format in play in the Phantasmagoria engine called ROBOT, with an extension of RBT. Fortunately, enough of the algorithms have been reverse engineered and re-implemented in ScummVM that I was able to sort out enough details for another subtitling project. That will be the subject of a future post.
See Also :
- Subtitling Sierra RBT Files : The followup in which I discuss how to scribble text on the other animation format
-
increasing memory occupancy while recording screen save to disk with ffmpeg [on hold]
19 mai 2016, par vbtangwonder if there are any resoures i didn’t free ?or do i need to do something special so that i can free these momery ?
ps. run the demo step by step, and found it has the same problem, until it quit the main function, it still have 40MB memory occupancy. And i found the memory increase obviously in the screen capture thread,but when it increased to about 150MB, it won’t increase, until i quit the program, it will have 40MB memory left. i feel confused.
pss. i download ffmpeg dev and shared version form here https://ffmpeg.zeranoe.com/builds/,it seems a dll of debug version ? do i need a release version ?
here is my demo code.#include "stdafx.h"
#ifdef __cplusplus
extern "C"
{
#endif
#include "libavcodec/avcodec.h"
#include "libavformat/avformat.h"
#include "libswscale/swscale.h"
#include "libavdevice/avdevice.h"
#include "libavutil/audio_fifo.h"
#pragma comment(lib, "avcodec.lib")
#pragma comment(lib, "avformat.lib")
#pragma comment(lib, "avutil.lib")
#pragma comment(lib, "avdevice.lib")
#pragma comment(lib, "avfilter.lib")
//#pragma comment(lib, "avfilter.lib")
//#pragma comment(lib, "postproc.lib")
//#pragma comment(lib, "swresample.lib")
#pragma comment(lib, "swscale.lib")
#ifdef __cplusplus
};
#endif
AVFormatContext *pFormatCtx_Video = NULL, *pFormatCtx_Audio = NULL, *pFormatCtx_Out = NULL;
AVCodecContext *pCodecCtx_Video;
AVCodec *pCodec_Video;
AVFifoBuffer *fifo_video = NULL;
AVAudioFifo *fifo_audio = NULL;
int VideoIndex, AudioIndex;
CRITICAL_SECTION AudioSection, VideoSection;
SwsContext *img_convert_ctx;
int frame_size = 0;
uint8_t *picture_buf = NULL, *frame_buf = NULL;
bool bCap = true;
DWORD WINAPI ScreenCapThreadProc( LPVOID lpParam );
DWORD WINAPI AudioCapThreadProc( LPVOID lpParam );
int OpenVideoCapture()
{
AVInputFormat *ifmt=av_find_input_format("gdigrab");
//
AVDictionary *options = NULL;
av_dict_set(&options, "framerate", "15", NULL);
//av_dict_set(&options,"offset_x","20",0);
//The distance from the top edge of the screen or desktop
//av_dict_set(&options,"offset_y","40",0);
//Video frame size. The default is to capture the full screen
//av_dict_set(&options,"video_size","320x240",0);
if(avformat_open_input(&pFormatCtx_Video, "desktop", ifmt, &options)!=0)
{
printf("Couldn't open input stream.（无法打开视频输入流）\n");
return -1;
}
if(avformat_find_stream_info(pFormatCtx_Video,NULL)<0)
{
printf("Couldn't find stream information.（无法获取视频流信息）\n");
return -1;
}
if (pFormatCtx_Video->streams[0]->codec->codec_type != AVMEDIA_TYPE_VIDEO)
{
printf("Couldn't find video stream information.（无法获取视频流信息）\n");
return -1;
}
pCodecCtx_Video = pFormatCtx_Video->streams[0]->codec;
pCodec_Video = avcodec_find_decoder(pCodecCtx_Video->codec_id);
if(pCodec_Video == NULL)
{
printf("Codec not found.（没有找到解码器）\n");
return -1;
}
if(avcodec_open2(pCodecCtx_Video, pCodec_Video, NULL) < 0)
{
printf("Could not open codec.（无法打开解码器）\n");
return -1;
}
img_convert_ctx = sws_getContext(pCodecCtx_Video->width, pCodecCtx_Video->height, pCodecCtx_Video->pix_fmt,
pCodecCtx_Video->width, pCodecCtx_Video->height, PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);
frame_size = avpicture_get_size(pCodecCtx_Video->pix_fmt, pCodecCtx_Video->width, pCodecCtx_Video->height);
//
fifo_video = av_fifo_alloc(30 * avpicture_get_size(AV_PIX_FMT_YUV420P, pCodecCtx_Video->width, pCodecCtx_Video->height));
return 0;
}
static char *dup_wchar_to_utf8(wchar_t *w)
{
char *s = NULL;
int l = WideCharToMultiByte(CP_UTF8, 0, w, -1, 0, 0, 0, 0);
s = (char *) av_malloc(l);
if (s)
WideCharToMultiByte(CP_UTF8, 0, w, -1, s, l, 0, 0);
return s;
}
int OpenAudioCapture()
{
//
AVInputFormat *pAudioInputFmt = av_find_input_format("dshow");
//
char * psDevName = dup_wchar_to_utf8(L"audio=virtual-audio-capturer");
if (avformat_open_input(&pFormatCtx_Audio, psDevName, pAudioInputFmt,NULL) < 0)
{
printf("Couldn't open input stream.（无法打开音频输入流）\n");
return -1;
}
if(avformat_find_stream_info(pFormatCtx_Audio,NULL)<0)
return -1;
if(pFormatCtx_Audio->streams[0]->codec->codec_type != AVMEDIA_TYPE_AUDIO)
{
printf("Couldn't find video stream information.（无法获取音频流信息）\n");
return -1;
}
AVCodec *tmpCodec = avcodec_find_decoder(pFormatCtx_Audio->streams[0]->codec->codec_id);
if(0 > avcodec_open2(pFormatCtx_Audio->streams[0]->codec, tmpCodec, NULL))
{
printf("can not find or open audio decoder!\n");
}
return 0;
}
int OpenOutPut()
{
AVStream *pVideoStream = NULL, *pAudioStream = NULL;
const char *outFileName = "test.mp4";
avformat_alloc_output_context2(&pFormatCtx_Out, NULL, NULL, outFileName);
if (pFormatCtx_Video->streams[0]->codec->codec_type == AVMEDIA_TYPE_VIDEO)
{
VideoIndex = 0;
pVideoStream = avformat_new_stream(pFormatCtx_Out, NULL);
if (!pVideoStream)
{
printf("can not new stream for output!\n");
return -1;
}
//set codec context param
pVideoStream->codec->codec = avcodec_find_encoder(AV_CODEC_ID_MPEG4);
pVideoStream->codec->height = pFormatCtx_Video->streams[0]->codec->height;
pVideoStream->codec->width = pFormatCtx_Video->streams[0]->codec->width;
pVideoStream->codec->time_base = pFormatCtx_Video->streams[0]->codec->time_base;
pVideoStream->codec->sample_aspect_ratio = pFormatCtx_Video->streams[0]->codec->sample_aspect_ratio;
// take first format from list of supported formats
pVideoStream->codec->pix_fmt = pFormatCtx_Out->streams[VideoIndex]->codec->codec->pix_fmts[0];
//open encoder
if (!pVideoStream->codec->codec)
{
printf("can not find the encoder!\n");
return -1;
}
if (pFormatCtx_Out->oformat->flags & AVFMT_GLOBALHEADER)
pVideoStream->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;
if ((avcodec_open2(pVideoStream->codec, pVideoStream->codec->codec, NULL)) < 0)
{
printf("can not open the encoder\n");
return -1;
}
}
if(pFormatCtx_Audio->streams[0]->codec->codec_type == AVMEDIA_TYPE_AUDIO)
{
AVCodecContext *pOutputCodecCtx;
AudioIndex = 1;
pAudioStream = avformat_new_stream(pFormatCtx_Out, NULL);
pAudioStream->codec->codec = avcodec_find_encoder(pFormatCtx_Out->oformat->audio_codec);
pOutputCodecCtx = pAudioStream->codec;
pOutputCodecCtx->sample_rate = pFormatCtx_Audio->streams[0]->codec->sample_rate;
pOutputCodecCtx->channel_layout = pFormatCtx_Out->streams[0]->codec->channel_layout;
pOutputCodecCtx->channels = av_get_channel_layout_nb_channels(pAudioStream->codec->channel_layout);
if(pOutputCodecCtx->channel_layout == 0)
{
pOutputCodecCtx->channel_layout = AV_CH_LAYOUT_STEREO;
pOutputCodecCtx->channels = av_get_channel_layout_nb_channels(pOutputCodecCtx->channel_layout);
}
pOutputCodecCtx->sample_fmt = pAudioStream->codec->codec->sample_fmts[0];
AVRational time_base={1, pAudioStream->codec->sample_rate};
pAudioStream->time_base = time_base;
//audioCodecCtx->time_base = time_base;
pOutputCodecCtx->codec_tag = 0;
if (pFormatCtx_Out->oformat->flags & AVFMT_GLOBALHEADER)
pOutputCodecCtx->flags |= CODEC_FLAG_GLOBAL_HEADER;
if (avcodec_open2(pOutputCodecCtx, pOutputCodecCtx->codec, 0) < 0)
{
//
return -1;
}
}
if (!(pFormatCtx_Out->oformat->flags & AVFMT_NOFILE))
{
if(avio_open(&pFormatCtx_Out->pb, outFileName, AVIO_FLAG_WRITE) < 0)
{
printf("can not open output file handle!\n");
return -1;
}
}
if(avformat_write_header(pFormatCtx_Out, NULL) < 0)
{
printf("can not write the header of the output file!\n");
return -1;
}
return 0;
}
int _tmain(int argc, _TCHAR* argv[])
{
av_register_all();
avdevice_register_all();
if (OpenVideoCapture() < 0)
{
return -1;
}
if (OpenAudioCapture() < 0)
{
return -1;
}
if (OpenOutPut() < 0)
{
return -1;
}
InitializeCriticalSection(&VideoSection);
InitializeCriticalSection(&AudioSection);
AVFrame *picture = av_frame_alloc();
int size = avpicture_get_size(pFormatCtx_Out->streams[VideoIndex]->codec->pix_fmt,
pFormatCtx_Out->streams[VideoIndex]->codec->width, pFormatCtx_Out->streams[VideoIndex]->codec->height);
picture_buf = new uint8_t[size];
avpicture_fill((AVPicture *)picture, picture_buf,
pFormatCtx_Out->streams[VideoIndex]->codec->pix_fmt,
pFormatCtx_Out->streams[VideoIndex]->codec->width,
pFormatCtx_Out->streams[VideoIndex]->codec->height);
//star cap screen thread
CreateThread( NULL, 0, ScreenCapThreadProc, 0, 0, NULL);
//star cap audio thread
CreateThread( NULL, 0, AudioCapThreadProc, 0, 0, NULL);
int64_t cur_pts_v=0,cur_pts_a=0;
int VideoFrameIndex = 0, AudioFrameIndex = 0;
while(1)
{
if (_kbhit() != 0 && bCap)
{
bCap = false;
Sleep(2000);//
}
if (fifo_audio && fifo_video)
{
int sizeAudio = av_audio_fifo_size(fifo_audio);
int sizeVideo = av_fifo_size(fifo_video);
//
if (av_audio_fifo_size(fifo_audio) <= pFormatCtx_Out->streams[AudioIndex]->codec->frame_size &&
av_fifo_size(fifo_video) <= frame_size && !bCap)
{
break;
}
}
if(av_compare_ts(cur_pts_v, pFormatCtx_Out->streams[VideoIndex]->time_base,
cur_pts_a,pFormatCtx_Out->streams[AudioIndex]->time_base) <= 0)
{
//read data from fifo
if (av_fifo_size(fifo_video) < frame_size && !bCap)
{
cur_pts_v = 0x7fffffffffffffff;
}
if(av_fifo_size(fifo_video) >= size)
{
EnterCriticalSection(&VideoSection);
av_fifo_generic_read(fifo_video, picture_buf, size, NULL);
LeaveCriticalSection(&VideoSection);
avpicture_fill((AVPicture *)picture, picture_buf,
pFormatCtx_Out->streams[VideoIndex]->codec->pix_fmt,
pFormatCtx_Out->streams[VideoIndex]->codec->width,
pFormatCtx_Out->streams[VideoIndex]->codec->height);
//pts = n * (（1 / timbase）/ fps);
picture->pts = VideoFrameIndex * ((pFormatCtx_Video->streams[0]->time_base.den / pFormatCtx_Video->streams[0]->time_base.num) / 15);
int got_picture = 0;
AVPacket pkt;
av_init_packet(&pkt);
pkt.data = NULL;
pkt.size = 0;
int ret = avcodec_encode_video2(pFormatCtx_Out->streams[VideoIndex]->codec, &pkt, picture, &got_picture);
if(ret < 0)
{
//
continue;
}
if (got_picture==1)
{
pkt.stream_index = VideoIndex;
pkt.pts = av_rescale_q_rnd(pkt.pts, pFormatCtx_Video->streams[0]->time_base,
pFormatCtx_Out->streams[VideoIndex]->time_base, (AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));
pkt.dts = av_rescale_q_rnd(pkt.dts, pFormatCtx_Video->streams[0]->time_base,
pFormatCtx_Out->streams[VideoIndex]->time_base, (AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));
pkt.duration = ((pFormatCtx_Out->streams[0]->time_base.den / pFormatCtx_Out->streams[0]->time_base.num) / 15);
cur_pts_v = pkt.pts;
ret = av_interleaved_write_frame(pFormatCtx_Out, &pkt);
//delete[] pkt.data;
av_free_packet(&pkt);
}
VideoFrameIndex++;
}
}
else
{
if (NULL == fifo_audio)
{
continue;//
}
if (av_audio_fifo_size(fifo_audio) < pFormatCtx_Out->streams[AudioIndex]->codec->frame_size && !bCap)
{
cur_pts_a = 0x7fffffffffffffff;
}
if(av_audio_fifo_size(fifo_audio) >=
(pFormatCtx_Out->streams[AudioIndex]->codec->frame_size > 0 ? pFormatCtx_Out->streams[AudioIndex]->codec->frame_size : 1024))
{
AVFrame *frame;
frame = av_frame_alloc();
frame->nb_samples = pFormatCtx_Out->streams[AudioIndex]->codec->frame_size>0 ? pFormatCtx_Out->streams[AudioIndex]->codec->frame_size: 1024;
frame->channel_layout = pFormatCtx_Out->streams[AudioIndex]->codec->channel_layout;
frame->format = pFormatCtx_Out->streams[AudioIndex]->codec->sample_fmt;
frame->sample_rate = pFormatCtx_Out->streams[AudioIndex]->codec->sample_rate;
av_frame_get_buffer(frame, 0);
EnterCriticalSection(&AudioSection);
av_audio_fifo_read(fifo_audio, (void **)frame->data,
(pFormatCtx_Out->streams[AudioIndex]->codec->frame_size > 0 ? pFormatCtx_Out->streams[AudioIndex]->codec->frame_size : 1024));
LeaveCriticalSection(&AudioSection);
if (pFormatCtx_Out->streams[0]->codec->sample_fmt != pFormatCtx_Audio->streams[AudioIndex]->codec->sample_fmt
|| pFormatCtx_Out->streams[0]->codec->channels != pFormatCtx_Audio->streams[AudioIndex]->codec->channels
|| pFormatCtx_Out->streams[0]->codec->sample_rate != pFormatCtx_Audio->streams[AudioIndex]->codec->sample_rate)
{
//
}
AVPacket pkt_out;
av_init_packet(&pkt_out);
int got_picture = -1;
pkt_out.data = NULL;
pkt_out.size = 0;
frame->pts = AudioFrameIndex * pFormatCtx_Out->streams[AudioIndex]->codec->frame_size;
if (avcodec_encode_audio2(pFormatCtx_Out->streams[AudioIndex]->codec, &pkt_out, frame, &got_picture) < 0)
{
printf("can not decoder a frame");
}
av_frame_free(&frame);
if (got_picture)
{
pkt_out.stream_index = AudioIndex;
pkt_out.pts = AudioFrameIndex * pFormatCtx_Out->streams[AudioIndex]->codec->frame_size;
pkt_out.dts = AudioFrameIndex * pFormatCtx_Out->streams[AudioIndex]->codec->frame_size;
pkt_out.duration = pFormatCtx_Out->streams[AudioIndex]->codec->frame_size;
cur_pts_a = pkt_out.pts;
int ret = av_interleaved_write_frame(pFormatCtx_Out, &pkt_out);
av_free_packet(&pkt_out);
}
AudioFrameIndex++;
}
}
}
delete[] picture_buf;
delete[]frame_buf;
av_fifo_free(fifo_video);
av_audio_fifo_free(fifo_audio);
av_write_trailer(pFormatCtx_Out);
avio_close(pFormatCtx_Out->pb);
avformat_free_context(pFormatCtx_Out);
if (pFormatCtx_Video != NULL)
{
avformat_close_input(&pFormatCtx_Video);
pFormatCtx_Video = NULL;
}
if (pFormatCtx_Audio != NULL)
{
avformat_close_input(&pFormatCtx_Audio);
pFormatCtx_Audio = NULL;
}
if (NULL != img_convert_ctx)
{
sws_freeContext(img_convert_ctx);
img_convert_ctx = NULL;
}
return 0;
}
DWORD WINAPI ScreenCapThreadProc( LPVOID lpParam )
{
AVPacket packet;/* = (AVPacket *)av_malloc(sizeof(AVPacket))*/;
int got_picture;
AVFrame *pFrame;
pFrame= av_frame_alloc();
AVFrame *picture = av_frame_alloc();
int size = avpicture_get_size(pFormatCtx_Out->streams[VideoIndex]->codec->pix_fmt,
pFormatCtx_Out->streams[VideoIndex]->codec->width, pFormatCtx_Out->streams[VideoIndex]->codec->height);
//picture_buf = new uint8_t[size];
avpicture_fill((AVPicture *)picture, picture_buf,
pFormatCtx_Out->streams[VideoIndex]->codec->pix_fmt,
pFormatCtx_Out->streams[VideoIndex]->codec->width,
pFormatCtx_Out->streams[VideoIndex]->codec->height);
// FILE *p = NULL;
// p = fopen("proc_test.yuv", "wb+");
av_init_packet(&packet);
int height = pFormatCtx_Out->streams[VideoIndex]->codec->height;
int width = pFormatCtx_Out->streams[VideoIndex]->codec->width;
int y_size=height*width;
while(bCap)
{
packet.data = NULL;
packet.size = 0;
if (av_read_frame(pFormatCtx_Video, &packet) < 0)
{
av_free_packet(&packet);
continue;
}
if(packet.stream_index == 0)
{
if (avcodec_decode_video2(pCodecCtx_Video, pFrame, &got_picture, &packet) < 0)
{
printf("Decode Error.（解码错误）\n");
continue;
}
if (got_picture)
{
sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0,
pFormatCtx_Out->streams[VideoIndex]->codec->height, picture->data, picture->linesize);
if (av_fifo_space(fifo_video) >= size)
{
EnterCriticalSection(&VideoSection);
av_fifo_generic_write(fifo_video, picture->data[0], y_size, NULL);
av_fifo_generic_write(fifo_video, picture->data[1], y_size/4, NULL);
av_fifo_generic_write(fifo_video, picture->data[2], y_size/4, NULL);
LeaveCriticalSection(&VideoSection);
}
}
}
av_free_packet(&packet);
//Sleep(50);
}
av_frame_free(&pFrame);
av_frame_free(&picture);
//delete[] picture_buf;
return 0;
}
DWORD WINAPI AudioCapThreadProc( LPVOID lpParam )
{
AVPacket pkt;
AVFrame *frame;
frame = av_frame_alloc();
int gotframe;
while(bCap)
{
pkt.data = NULL;
pkt.size = 0;
if(av_read_frame(pFormatCtx_Audio,&pkt) < 0)
{
av_free_packet(&pkt);
continue;
}
if (avcodec_decode_audio4(pFormatCtx_Audio->streams[0]->codec, frame, &gotframe, &pkt) < 0)
{
av_frame_free(&frame);
printf("can not decoder a frame");
break;
}
av_free_packet(&pkt);
if (!gotframe)
{
continue;//
}
if (NULL == fifo_audio)
{
fifo_audio = av_audio_fifo_alloc(pFormatCtx_Audio->streams[0]->codec->sample_fmt,
pFormatCtx_Audio->streams[0]->codec->channels, 30 * frame->nb_samples);
}
int buf_space = av_audio_fifo_space(fifo_audio);
if (av_audio_fifo_space(fifo_audio) >= frame->nb_samples)
{
EnterCriticalSection(&AudioSection);
av_audio_fifo_write(fifo_audio, (void **)frame->data, frame->nb_samples);
LeaveCriticalSection(&AudioSection);
}
}
av_frame_free(&frame);
return 0;
} -
Use FFSERVER's C API to receive feed at an Android Client
17 mai 2016, par user3159395I want to stream live feed of a device like PC to an Android Client using RTSP protocol. Now I know this can be achieved using "ffmpeg" and "ffserver". But I wish to receive the stream frame by frame becuase I have process ( some image processing ) each frame. Thus, I am guessing I need to use ffserver’s C API to get frame one by one.
- Does ffserver have a C API ?
- If answer to 1. was yes, please support your answer with a concise example, perhaps simple C program to get frames from a URL feed.
- Is any special configuration needed for RTSP protocol ?
Please help me as I have already searched thoroughly.
Syndiquer tout le site
