
Recherche avancée
Médias (91)
-
Spoon - Revenge !
15 septembre 2011, par
Mis à jour : Septembre 2011
Langue : English
Type : Audio
-
My Morning Jacket - One Big Holiday
15 septembre 2011, par
Mis à jour : Septembre 2011
Langue : English
Type : Audio
-
Zap Mama - Wadidyusay ?
15 septembre 2011, par
Mis à jour : Septembre 2011
Langue : English
Type : Audio
-
David Byrne - My Fair Lady
15 septembre 2011, par
Mis à jour : Septembre 2011
Langue : English
Type : Audio
-
Beastie Boys - Now Get Busy
15 septembre 2011, par
Mis à jour : Septembre 2011
Langue : English
Type : Audio
-
Granite de l’Aber Ildut
9 septembre 2011, par
Mis à jour : Septembre 2011
Langue : français
Type : Texte
Autres articles (30)
-
Le plugin : Podcasts.
14 juillet 2010, parLe problème du podcasting est à nouveau un problème révélateur de la normalisation des transports de données sur Internet.
Deux formats intéressants existent : Celui développé par Apple, très axé sur l’utilisation d’iTunes dont la SPEC est ici ; Le format "Media RSS Module" qui est plus "libre" notamment soutenu par Yahoo et le logiciel Miro ;
Types de fichiers supportés dans les flux
Le format d’Apple n’autorise que les formats suivants dans ses flux : .mp3 audio/mpeg .m4a audio/x-m4a .mp4 (...) -
Encoding and processing into web-friendly formats
13 avril 2011, parMediaSPIP automatically converts uploaded files to internet-compatible formats.
Video files are encoded in MP4, Ogv and WebM (supported by HTML5) and MP4 (supported by Flash).
Audio files are encoded in MP3 and Ogg (supported by HTML5) and MP3 (supported by Flash).
Where possible, text is analyzed in order to retrieve the data needed for search engine detection, and then exported as a series of image files.
All uploaded files are stored online in their original format, so you can (...) -
Les images
15 mai 2013
Sur d’autres sites (7388)
-
FFmpeg - MJPEG decoding gives inconsistent values
28 décembre 2016, par ahmadhI have a set of JPEG frames which I am muxing into an avi, which gives me a mjpeg video. This is the command I run on the console :
ffmpeg -y -start_number 0 -i %06d.JPEG -codec copy vid.avi
When I try to demux the video using ffmpeg C api, I get frames which are slightly different in values. Demuxing code looks something like this :
AVFormatContext* fmt_ctx = NULL;
AVCodecContext* cdc_ctx = NULL;
AVCodec* vid_cdc = NULL;
int ret;
unsigned int height, width;
....
// read_nframes is the number of frames to read
output_arr = new unsigned char [height * width * 3 *
sizeof(unsigned char) * read_nframes];
avcodec_open2(cdc_ctx, vid_cdc, NULL);
int num_bytes;
uint8_t* buffer = NULL;
const AVPixelFormat out_format = AV_PIX_FMT_RGB24;
num_bytes = av_image_get_buffer_size(out_format, width, height, 1);
buffer = (uint8_t*)av_malloc(num_bytes * sizeof(uint8_t));
AVFrame* vid_frame = NULL;
vid_frame = av_frame_alloc();
AVFrame* conv_frame = NULL;
conv_frame = av_frame_alloc();
av_image_fill_arrays(conv_frame->data, conv_frame->linesize, buffer,
out_format, width, height, 1);
struct SwsContext *sws_ctx = NULL;
sws_ctx = sws_getContext(width, height, cdc_ctx->pix_fmt,
width, height, out_format,
SWS_BILINEAR, NULL,NULL,NULL);
int frame_num = 0;
AVPacket vid_pckt;
while (av_read_frame(fmt_ctx, &vid_pckt) >=0) {
ret = avcodec_send_packet(cdc_ctx, &vid_pckt);
if (ret < 0)
break;
ret = avcodec_receive_frame(cdc_ctx, vid_frame);
if (ret < 0 && ret != AVERROR(EAGAIN) && ret != AVERROR_EOF)
break;
if (ret >= 0) {
// convert image from native format to planar GBR
sws_scale(sws_ctx, vid_frame->data,
vid_frame->linesize, 0, vid_frame->height,
conv_frame->data, conv_frame->linesize);
unsigned char* r_ptr = output_arr +
(height * width * sizeof(unsigned char) * 3 * frame_num);
unsigned char* g_ptr = r_ptr + (height * width * sizeof(unsigned char));
unsigned char* b_ptr = g_ptr + (height * width * sizeof(unsigned char));
unsigned int pxl_i = 0;
for (unsigned int r = 0; r < height; ++r) {
uint8_t* avframe_r = conv_frame->data[0] + r*conv_frame->linesize[0];
for (unsigned int c = 0; c < width; ++c) {
r_ptr[pxl_i] = avframe_r[0];
g_ptr[pxl_i] = avframe_r[1];
b_ptr[pxl_i] = avframe_r[2];
avframe_r += 3;
++pxl_i;
}
}
++frame_num;
if (frame_num >= read_nframes)
break;
}
}
...In my experience around two-thirds of the pixel values are different, each by +-1 (in a range of [0,255]). I am wondering is it due to some decoding scheme FFmpeg uses for reading JPEG frames ? I tried encoding and decoding png frames, and it works perfectly fine. I am sure this is something to do with the libav decoding process because the MD5 values are consistent between the images and the video :
ffmpeg -i %06d.JPEG -f framemd5 -
ffmpeg -i vid.avi -f framemd5 -In short my goal is to get the same pixel by pixel values for each JPEG frame as I would I have gotten if I was reading the JPEG images directly. Here is the stand-alone bitbucket code I used. It includes cmake files to build code, and a couple of jpeg frames with the converted avi file to test this problem. (give ’—filetype png’ to test the png decoding).
-
How to using every 5 sec generate video output File Path to Encode with RTMP Formate write data in ios ? [on hold]
16 juillet 2015, par Sandeep Joshi(void) segmentRecording:(NSTimer*)timer {
if (!shouldBeRecording) {
[timer invalidate];
}
AVAssetWriter *tempAssetWriter = self.assetWriter;
AVAssetWriterInput *tempAudioEncoder = self.audioEncoder;
AVAssetWriterInput *tempVideoEncoder = self.videoEncoder;
self.assetWriter = queuedAssetWriter;
self.audioEncoder = queuedAudioEncoder;
self.videoEncoder = queuedVideoEncoder;
NSLog(@"Switching encoders");
dispatch_async(segmentingQueue, ^{
if (tempAssetWriter.status == AVAssetWriterStatusWriting) {
@try {
[tempAudioEncoder markAsFinished];
[tempVideoEncoder markAsFinished];
[tempAssetWriter finishWritingWithCompletionHandler:^{
if (tempAssetWriter.status == AVAssetWriterStatusFailed) {
[self showError:tempAssetWriter.error];
} else {
[self uploadLocalURL:tempAssetWriter.outputURL];
}
}];
}
@catch (NSException *exception) {
NSLog(@"Caught exception: %@", [exception description]);
//[BugSenseController logException:exception withExtraData:nil];
}
}
self.segmentCount++;
if (self.readyToRecordAudio && self.readyToRecordVideo) {
NSError *error = nil;
self.queuedAssetWriter = [[AVAssetWriter alloc] initWithURL:[OWUtilities urlForRecordingSegmentCount:segmentCount basePath:self.basePath] fileType:(NSString *)kUTTypeMPEG4 error:&error];
if (error) {
[self showError:error];
}
self.queuedVideoEncoder = [self setupVideoEncoderWithAssetWriter:self.queuedAssetWriter formatDescription:videoFormatDescription bitsPerSecond:videoBPS];
self.queuedAudioEncoder = [self setupAudioEncoderWithAssetWriter:self.queuedAssetWriter formatDescription:audioFormatDescription bitsPerSecond:audioBPS];
//NSLog(@"Encoder switch finished");
}
});}
(void) uploadLocalURL:(NSURL*)url {
NSLog(@"upload local url: %@", url);
NSString *inputPath = [url path];
NSString *outputPath = [inputPath stringByReplacingOccurrencesOfString:@".mp4" withString:@".ts"];
NSString *outputFileName = [outputPath lastPathComponent];
NSDictionary *options = @{kFFmpegOutputFormatKey: @"mpegts"};
NSLog(@"%@ conversion...", outputFileName);
[ffmpegWrapper convertInputPath:[url path] outputPath:outputPath options:options progressBlock:nil completionBlock:^(BOOL success, NSError *error) {
if (success) {
if (!isRtmpConnected) {
isRtmpConnected = [rtmp openWithURL:HOST_URL enableWrite:YES];
}
isRtmpConnected = [rtmp isConnected];
if (isRtmpConnected) {
NSData *video = [NSData dataWithContentsOfURL:[NSURL URLWithString:outputPath]];
NSUInteger length = [video length];
NSUInteger chunkSize = 1024 * 5;;
NSUInteger offset = 0;
NSLog(@"original video length: %lu \n chunkSize : %lu", length,chunkSize);
// Let's split video to small chunks to publish to media server
do {
NSUInteger thisChunkSize = length - offset > chunkSize ? chunkSize : length - offset;
NSData* chunk = [NSData dataWithBytesNoCopy:(char *)[video bytes] + offset
length:thisChunkSize
freeWhenDone:NO];
offset += thisChunkSize;
// Write new chunk to rtmp server
NSLog(@"%lu", (unsigned long)[rtmp write:chunk]);
sleep(1);
} while (offset < length);
}else{
[rtmp close];
}
} else {
NSLog(@"conversion error: %@", error.userInfo);
}
}];}This code use for live streaming for send data using RTMP Wrapper.
Not write in Socket properly because every 5 second to generate different file output file.This is proper way ?
I have no idea how to get NSData in proper way.
Please help me .
-
Compiling ffmpeg for iOS and gas-preprocessor.pl
16 mai 2017, par user500I want to compile ffmpeg for iOS. I did it a few times before. But now I’m on clean new Mavericks and on configure I’m always getting
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
GNU assembler not found, install gas-preprocessor
If you think configure made a mistake, make sure you are using the latest
version from Git. If the latest version fails, report the problem to the
ffmpeg-user@ffmpeg.org mailing list or IRC #ffmpeg on irc.freenode.net.
Include the log file "config.log" produced by configure as this will help
solving the problem.I have current Xcode installed. Also brews. And current
gas-preprocessor.pl
(https://github.com/yuvi/gas-preprocessor) inusr/bin
and also inusr/local/bin
.
On
perl /usr/bin/gas-preprocessor.pl gcc
I’m gettingUnrecognized input filetype at /usr/bin/gas-preprocessor.pl line 33.
This config works :
./configure \
--extra-cflags='-arch arm64 -mios-version-min=7.0 -mthumb' \
--extra-ldflags='-arch arm64 -mios-version-min=7.0' \
--enable-cross-compile \
--arch=arm64 \
--target-os=darwin \
--cc=/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang \
--sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk \
--prefix=arm64 \
--disable-doc \
--disable-shared \
--disable-everything \
--enable-static \
--enable-pic \
--disable-muxers \
--enable-muxer=flv \
--disable-demuxers \
--enable-demuxer=h264 \
--enable-demuxer=pcm_s16le \
--disable-devices \
--disable-parsers \
--enable-parser=h264 \
--disable-encoders \
--enable-encoder=aac \
--disable-decoders \
--enable-decoder=h264 \
--enable-decoder=pcm_s16le \
--disable-protocols \
--enable-protocol=rtmp \
--disable-filters \
--disable-bsfs
This config throws error above (GNU assembler not found, install gas-preprocessor) :
./configure \
--cpu=cortex-a8 \
--extra-cflags='-arch armv7 -mios-version-min=7.0 -mthumb' \
--extra-ldflags='-arch armv7 -mios-version-min=7.0' \
--enable-cross-compile \
--arch=armv7 \
--target-os=darwin \
--cc=/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang \
--sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk \
--prefix=armv7 \
--disable-doc \
--disable-shared \
--disable-everything \
--enable-static \
--enable-pic \
--disable-muxers \
--enable-muxer=flv \
--disable-demuxers \
--enable-demuxer=h264 \
--enable-demuxer=pcm_s16le \
--disable-devices \
--disable-parsers \
--enable-parser=h264 \
--disable-encoders \
--enable-encoder=aac \
--disable-decoders \
--enable-decoder=h264 \
--enable-decoder=pcm_s16le \
--disable-protocols \
--enable-protocol=rtmp \
--disable-filters \
--disable-bsfs