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The Slip - Artworks
26 septembre 2011, par
Mis à jour : Septembre 2011
Langue : English
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Sur d’autres sites (13307)
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c++ - using FFmpeg encode and UDP with a Webcam
14 mars, par RendresI'm trying to get frames from a Webcam using OpenCV, encode them with FFmpeg and send them using UDP.



I did before a similar project that instead of sending the packets with UDP, it saved them in a video file.



My code is.



#include 
#include 
#include 
#include 

extern "C" {
#include <libavcodec></libavcodec>avcodec.h>
#include <libavformat></libavformat>avformat.h>
#include <libavutil></libavutil>opt.h>
#include <libavutil></libavutil>imgutils.h>
#include <libavutil></libavutil>mathematics.h>
#include <libswscale></libswscale>swscale.h>
#include <libswresample></libswresample>swresample.h>
}

#include <opencv2></opencv2>opencv.hpp>

using namespace std;
using namespace cv;

#define WIDTH 640
#define HEIGHT 480
#define CODEC_ID AV_CODEC_ID_H264
#define STREAM_PIX_FMT AV_PIX_FMT_YUV420P

static AVFrame *frame, *pFrameBGR;

int main(int argc, char **argv)
{
VideoCapture cap(0);
const char *url = "udp://127.0.0.1:8080";

AVFormatContext *formatContext;
AVStream *stream;
AVCodec *codec;
AVCodecContext *c;
AVDictionary *opts = NULL;

int ret, got_packet;

if (!cap.isOpened())
{
 return -1;
}

av_log_set_level(AV_LOG_TRACE);

av_register_all();
avformat_network_init();

avformat_alloc_output_context2(&formatContext, NULL, "h264", url);
if (!formatContext)
{
 av_log(NULL, AV_LOG_FATAL, "Could not allocate an output context for '%s'.\n", url);
}

codec = avcodec_find_encoder(CODEC_ID);
if (!codec)
{
 av_log(NULL, AV_LOG_ERROR, "Could not find encoder.\n");
}

stream = avformat_new_stream(formatContext, codec);

c = avcodec_alloc_context3(codec);

stream->id = formatContext->nb_streams - 1;
stream->time_base = (AVRational){1, 25};

c->codec_id = CODEC_ID;
c->bit_rate = 400000;
c->width = WIDTH;
c->height = HEIGHT;
c->time_base = stream->time_base;
c->gop_size = 12;
c->pix_fmt = STREAM_PIX_FMT;

if (formatContext->flags & AVFMT_GLOBALHEADER)
 c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;

av_dict_set(&opts, "preset", "fast", 0);

av_dict_set(&opts, "tune", "zerolatency", 0);

ret = avcodec_open2(c, codec, NULL);
if (ret < 0)
{
 av_log(NULL, AV_LOG_ERROR, "Could not open video codec.\n");
}

pFrameBGR = av_frame_alloc();
if (!pFrameBGR)
{
 av_log(NULL, AV_LOG_ERROR, "Could not allocate video frame.\n");
}

frame = av_frame_alloc();
if (!frame)
{
 av_log(NULL, AV_LOG_ERROR, "Could not allocate video frame.\n");
}

frame->format = c->pix_fmt;
frame->width = c->width;
frame->height = c->height;

ret = avcodec_parameters_from_context(stream->codecpar, c);
if (ret < 0)
{
 av_log(NULL, AV_LOG_ERROR, "Could not open video codec.\n");
}

av_dump_format(formatContext, 0, url, 1);

ret = avformat_write_header(formatContext, NULL);
if (ret != 0)
{
 av_log(NULL, AV_LOG_ERROR, "Failed to connect to '%s'.\n", url);
}

Mat image(Size(HEIGHT, WIDTH), CV_8UC3);
SwsContext *swsctx = sws_getContext(WIDTH, HEIGHT, AV_PIX_FMT_BGR24, WIDTH, HEIGHT, AV_PIX_FMT_YUV420P, SWS_BILINEAR, NULL, NULL, NULL);
int frame_pts = 0;

while (1)
{
 cap >> image;

 int numBytesYUV = av_image_get_buffer_size(STREAM_PIX_FMT, WIDTH, HEIGHT, 1);
 uint8_t *bufferYUV = (uint8_t *)av_malloc(numBytesYUV * sizeof(uint8_t));

 avpicture_fill((AVPicture *)pFrameBGR, image.data, AV_PIX_FMT_BGR24, WIDTH, HEIGHT);
 avpicture_fill((AVPicture *)frame, bufferYUV, STREAM_PIX_FMT, WIDTH, HEIGHT);

 sws_scale(swsctx, (uint8_t const *const *)pFrameBGR->data, pFrameBGR->linesize, 0, HEIGHT, frame->data, frame->linesize);

 AVPacket pkt = {0};
 av_init_packet(&pkt);

 frame->pts = frame_pts;

 ret = avcodec_encode_video2(c, &pkt, frame, &got_packet);
 if (ret < 0)
 {
 av_log(NULL, AV_LOG_ERROR, "Error encoding frame\n");
 }

 if (got_packet)
 {
 pkt.pts = av_rescale_q_rnd(pkt.pts, c->time_base, stream->time_base, AVRounding(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX));
 pkt.dts = av_rescale_q_rnd(pkt.dts, c->time_base, stream->time_base, AVRounding(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX));
 pkt.duration = av_rescale_q(pkt.duration, c->time_base, stream->time_base);
 pkt.stream_index = stream->index;

 return av_interleaved_write_frame(formatContext, &pkt);

 cout << "Seguro que si" << endl;
 }
 frame_pts++;
}

avcodec_free_context(&c);
av_frame_free(&frame);
avformat_free_context(formatContext);

return 0;
}



The code compiles but it returns Segmentation fault in the function av_interleaved_write_frame(). I've tried several implementations or several codecs (in this case I'm using libopenh264, but using mpeg2video returns the same segmentation fault). I tried also with av_write_frame() but it returns the same error.



As I told before, I only want to grab frames from a webcam connected via USB, encode them to H264 and send the packets through UDP to another PC.



My console log when I run the executable is.



[100%] Built target display
[OpenH264] this = 0x0x244b4f0, Info:CWelsH264SVCEncoder::SetOption():ENCODER_OPTION_TRACE_CALLBACK callback = 0x7f0c302a87c0.
[libopenh264 @ 0x244aa00] [OpenH264] this = 0x0x244b4f0, Info:CWelsH264SVCEncoder::InitEncoder(), openh264 codec version = 5a5c4f1
[libopenh264 @ 0x244aa00] [OpenH264] this = 0x0x244b4f0, Info:iUsageType = 0,iPicWidth= 640;iPicHeight= 480;iTargetBitrate= 400000;iMaxBitrate= 400000;iRCMode= 0;iPaddingFlag= 0;iTemporalLayerNum= 1;iSpatialLayerNum= 1;fFrameRate= 25.000000f;uiIntraPeriod= 12;eSpsPpsIdStrategy = 0;bPrefixNalAddingCtrl = 0;bSimulcastAVC=0;bEnableDenoise= 0;bEnableBackgroundDetection= 1;bEnableSceneChangeDetect = 1;bEnableAdaptiveQuant= 1;bEnableFrameSkip= 0;bEnableLongTermReference= 0;iLtrMarkPeriod= 30, bIsLosslessLink=0;iComplexityMode = 0;iNumRefFrame = 1;iEntropyCodingModeFlag = 0;uiMaxNalSize = 0;iLTRRefNum = 0;iMultipleThreadIdc = 1;iLoopFilterDisableIdc = 0 (offset(alpha/beta): 0,0;iComplexityMode = 0,iMaxQp = 51;iMinQp = 0)
[libopenh264 @ 0x244aa00] [OpenH264] this = 0x0x244b4f0, Info:sSpatialLayers[0]: .iVideoWidth= 640; .iVideoHeight= 480; .fFrameRate= 25.000000f; .iSpatialBitrate= 400000; .iMaxSpatialBitrate= 400000; .sSliceArgument.uiSliceMode= 1; .sSliceArgument.iSliceNum= 0; .sSliceArgument.uiSliceSizeConstraint= 1500;uiProfileIdc = 66;uiLevelIdc = 41
[libopenh264 @ 0x244aa00] [OpenH264] this = 0x0x244b4f0, Warning:SliceArgumentValidationFixedSliceMode(), unsupported setting with Resolution and uiSliceNum combination under RC on! So uiSliceNum is changed to 6!
[libopenh264 @ 0x244aa00] [OpenH264] this = 0x0x244b4f0, Info:Setting MaxSpatialBitrate (400000) the same at SpatialBitrate (400000) will make the actual bit rate lower than SpatialBitrate
[libopenh264 @ 0x244aa00] [OpenH264] this = 0x0x244b4f0, Warning:bEnableFrameSkip = 0,bitrate can't be controlled for RC_QUALITY_MODE,RC_BITRATE_MODE and RC_TIMESTAMP_MODE without enabling skip frame.
[libopenh264 @ 0x244aa00] [OpenH264] this = 0x0x244b4f0, Warning:Change QP Range from(0,51) to (12,42)
[libopenh264 @ 0x244aa00] [OpenH264] this = 0x0x244b4f0, Info:WELS CPU features/capacities (0x4007fe3f) detected: HTT: Y, MMX: Y, MMXEX: Y, SSE: Y, SSE2: Y, SSE3: Y, SSSE3: Y, SSE4.1: Y, SSE4.2: Y, AVX: Y, FMA: Y, X87-FPU: Y, 3DNOW: N, 3DNOWEX: N, ALTIVEC: N, CMOV: Y, MOVBE: Y, AES: Y, NUMBER OF LOGIC PROCESSORS ON CHIP: 8, CPU CACHE LINE SIZE (BYTES): 64
[libopenh264 @ 0x244aa00] [OpenH264] this = 0x0x244b4f0, Info:WelsInitEncoderExt() exit, overall memory usage: 4542878 bytes
[libopenh264 @ 0x244aa00] [OpenH264] this = 0x0x244b4f0, Info:WelsInitEncoderExt(), pCtx= 0x0x245a400.
Output #0, h264, to 'udp://192.168.100.39:8080':
Stream #0:0, 0, 1/25: Video: h264 (libopenh264), 1 reference frame, yuv420p, 640x480 (0x0), 0/1, q=2-31, 400 kb/s, 25 tbn
[libopenh264 @ 0x244aa00] [OpenH264] this = 0x0x244b4f0, Debug:RcUpdateIntraComplexity iFrameDqBits = 385808,iQStep= 2016,iIntraCmplx = 777788928
[libopenh264 @ 0x244aa00] [OpenH264] this = 0x0x244b4f0, Debug:[Rc]Layer 0: Frame timestamp = 0, Frame type = 2, encoding_qp = 30, average qp = 30, max qp = 33, min qp = 27, index = 0, iTid = 0, used = 385808, bitsperframe = 16000, target = 64000, remainingbits = -257808, skipbuffersize = 200000
[libopenh264 @ 0x244aa00] [OpenH264] this = 0x0x244b4f0, Debug:WelsEncoderEncodeExt() OutputInfo iLayerNum = 2,iFrameSize = 48252
[libopenh264 @ 0x244aa00] [OpenH264] this = 0x0x244b4f0, Debug:WelsEncoderEncodeExt() OutputInfo iLayerId = 0,iNalType = 0,iNalCount = 2, first Nal Length=18,uiSpatialId = 0,uiTemporalId = 0,iSubSeqId = 0
[libopenh264 @ 0x244aa00] [OpenH264] this = 0x0x244b4f0, Debug:WelsEncoderEncodeExt() OutputInfo iLayerId = 1,iNalType = 1,iNalCount = 6, first Nal Length=6057,uiSpatialId = 0,uiTemporalId = 0,iSubSeqId = 0
[libopenh264 @ 0x244aa00] 6 slices
./scriptBuild.sh: line 20: 10625 Segmentation fault (core dumped) ./display



As you can see, FFmpeg uses libopenh264 and configures it correctly. However, no matter what. It always returns the same Segmentation fault error...



I've used commands like this.



ffmpeg -s 640x480 -f video4linux2 -i /dev/video0 -r 30 -vcodec libopenh264 -an -f h264 udp://127.0.0.1:8080



And it works perfectly, but I need to process the frames before sending them. Thats why I'm trying to use the libs.



My FFmpeg version is.



ffmpeg version 3.3.6 Copyright (c) 2000-2017 the FFmpeg developers
built with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04.3)
configuration: --disable-yasm --enable-shared --enable-libopenh264 --cc='gcc -fPIC'
libavutil 55. 58.100 / 55. 58.100
libavcodec 57. 89.100 / 57. 89.100
libavformat 57. 71.100 / 57. 71.100
libavdevice 57. 6.100 / 57. 6.100
libavfilter 6. 82.100 / 6. 82.100
libswscale 4. 6.100 / 4. 6.100
libswresample 2. 7.100 / 2. 7.100



I tried to get more information of the error using gbd, but it didn't give me debugging info.



How can I solve this problem ? I don't know what else can I try...



Thank you !


-
ffmpeg version 2.6.8 : Stream specifier ':a' in filtergraph description matches no streams
16 décembre 2020, par AshitakaI am not getting why this isn't working.. I have tried to get the video streams with [0:v]/[0:1]/[0:v:0] & the audio streams with [0:a]/[0:0]/[0:0:0].
nothing worked.


Explaining the inputs :


1.1st input stream is a video that can be of varying resolution on which the filter adds a padding on to make it 600:480.


2.2nd input is an overlay png which is already at 5:4 ratio.. just making it 600:480 before it gets overlaid in the filter.


3.3rd & 4th ones are also videos which I don't care if they get stretched.. n they are getting stretched to 600:480.


4.so finally there are 3 streams 1 overlaid video 2 stretched videos which needs to be concatenated.


here's the command :


ffmpeg 
-i '/home/vidinflux/public_html/assets/temp/2018020116464612/2018020116464612.mp4' 
-i '/home/vidinflux/public_html/assets/temp/2018020116464612/2018020116464612_overlay.png' 
-i '/home/vidinflux/public_html/assets/user/736/video/Lines1.mp4' 
-i '/home/vidinflux/public_html/assets/user/736/video/Lines11.mp4' 
-filter_complex
"[0:v]trim=0:138,setpts=PTS-STARTPTS[v0];[0:a]atrim=0:138,asetpts=PTS-STARTPTS[a0];[v0]scale='gte(iw/ih\,600/480)*600+lt(iw/ih\,600/480)*((480*iw)/ih):lte(iw/ih\,600/480)*480+gt(iw/ih\,600/480)*((600*ih)/iw)',pad='600:480:(600-gte(iw/ih\,600/480)*600-lt(iw/ih\,600/480)*((480*iw)/ih))/2:(480-lte(iw/ih\,600/480)*480-gt(iw/ih\,600/480)*((600*ih)/iw))/2:black'[x];[1:v]scale=600:480[y];[x][y]overlay=0:0[z];[2:v]scale=600:480,setsar=1:1[x0];[3:v]scale=600:480,setsar=1:1[x1];[x0][2:a][z][a0][x1][3:a]concat=n=3:v=1:a=1[v][a]" 
-map "[v]" 
-map "[a]" 
-c:v libx264 
-shortest /home/vidinflux/public_html/assets/temp/2018020116464612/2018020116464612_final.mp4


this is the complete error I am getting :


Stream specifier ':a' in filtergraph description [0:v]trim=0:138,setpts=PTS-STARTPTS[v0];[0:a]atrim=0:138,asetpts=PTS-STARTPTS[a0];[v0]scale='gte(iw/ih\,600/480)*600+lt(iw/ih\,600/480)*((480*iw)/ih):lte(iw/ih\,600/480)*480+gt(iw/ih\,600/480)*((600*ih)/iw)',pad='600:480:(600-gte(iw/ih\,600/480)*600-lt(iw/ih\,600/480)*((480*iw)/ih))/2:(480-lte(iw/ih\,600/480)*480-gt(iw/ih\,600/480)*((600*ih)/iw))/2:black'[x];[1:v]scale=600:480[y];[x][y]overlay=0:0[z];[2:v]scale=600:480,setsar=1:1[x0];[3:v]scale=600:480,setsar=1:1[x1];[x0][2:a][z][a0][x1][3:a]concat=n=3:v=1:a=1[v][a] matches no streams.


also there are these warnings :


[Parsed_setsar_9 @ 0x219fba0] num:den syntax is deprecated, please use num/den or named options instead
[Parsed_setsar_11 @ 0x21a4840] num:den syntax is deprecated, please use num/den or named options instead


Complete log as requested :


[root@cloud ~]# ffmpeg -i '/home/vidinflux/public_html/assets/temp/2018020116464612/2018020116464612.mp4' -i '/home/vidinflux/public_html/assets/temp/2018020116464612/2018020116464612_overlay.png' -i '/home/vidinflux/public_html/assets/user/736/video/Lines1.mp4' -i '/home/vidinflux/public_html/assets/user/736/video/Lines11.mp4' -filter_complex \ "[0:v]trim=0:138,setpts=PTS-STARTPTS[v0];[0:a]atrim=0:138,asetpts=PTS-STARTPTS[a0];[v0]scale='gte(iw/ih\,600/480)*600+lt(iw/ih\,600/480)*((480*iw)/ih):lte(iw/ih\,600/480)*480+gt(iw/ih\,600/480)*((600*ih)/iw)',pad='600:480:(600-gte(iw/ih\,600/480)*600-lt(iw/ih\,600/480)*((480*iw)/ih))/2:(480-lte(iw/ih\,600/480)*480-gt(iw/ih\,600/480)*((600*ih)/iw))/2:black'[x];[1:v]scale=600:480[y];[x][y]overlay=0:0[z];[2:v]scale=600:480,setsar=1:1[x0];[3:v]scale=600:480,setsar=1:1[x1];[x0][2:a][z][a0][x1][3:a]concat=n=3:v=1:a=1[v][a]" -map "[v]" -map "[a]" -c:v libx264 -shortest /home/vidinflux/public_html/assets/temp/2018020116464612/2018020116464612_final.mp4
ffmpeg version 2.6.8 Copyright (c) 2000-2016 the FFmpeg developers
 built with gcc 4.4.7 (GCC) 20120313 (Red Hat 4.4.7-16)
 configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg --incdir=/usr/include/ffmpeg --libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --optflags='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic' --enable-bzlib --disable-crystalhd --enable-gnutls --enable-ladspa --enable-libass --enable-libdc1394 --enable-libfaac --enable-nonfree --disable-indev=jack --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-openal --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libv4l2 --enable-libx264 --enable-libx265 --enable-libxvid --enable-x11grab --enable-avfilter --enable-avresample --enable-postproc --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-stripping --shlibdir=/usr/lib64 --enable-runtime-cpudetect
 libavutil 54. 20.100 / 54. 20.100
 libavcodec 56. 26.100 / 56. 26.100
 libavformat 56. 25.101 / 56. 25.101
 libavdevice 56. 4.100 / 56. 4.100
 libavfilter 5. 11.102 / 5. 11.102
 libavresample 2. 1. 0 / 2. 1. 0
 libswscale 3. 1.101 / 3. 1.101
 libswresample 1. 1.100 / 1. 1.100
 libpostproc 53. 3.100 / 53. 3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/home/vidinflux/public_html/assets/temp/2018020116464612/2018020116464612.mp4':
 Metadata:
 major_brand : mp42
 minor_version : 0
 compatible_brands: isommp42
 creation_time : 2017-08-21 02:23:24
 Duration: 00:02:17.23, start: 0.000000, bitrate: 417 kb/s
 Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p(tv, bt709), 640x360 [SAR 1:1 DAR 16:9], 318 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
 Metadata:
 handler_name : VideoHandler
 Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 96 kb/s (default)
 Metadata:
 creation_time : 2017-08-21 02:23:24
 handler_name : IsoMedia File Produced by Google, 5-11-2011
Input #1, png_pipe, from '/home/vidinflux/public_html/assets/temp/2018020116464612/2018020116464612_overlay.png':
 Duration: N/A, bitrate: N/A
 Stream #1:0: Video: png, rgba, 600x479, 25 tbr, 25 tbn, 25 tbc
Input #2, mov,mp4,m4a,3gp,3g2,mj2, from '/home/vidinflux/public_html/assets/user/736/video/Lines1.mp4':
 Metadata:
 major_brand : mp42
 minor_version : 1
 compatible_brands: mp41mp42isom
 creation_time : 2018-01-31 22:40:09
 Duration: 00:00:04.90, start: 0.103811, bitrate: 846 kb/s
 Stream #2:0(und): Video: h264 (Baseline) (avc1 / 0x31637661), yuv420p(tv, smpte170m/bt470bg/bt709), 1920x1080, 827 kb/s, SAR 1:1 DAR 16:9, 30 fps, 30 tbr, 90k tbn, 180k tbc (default)
 Metadata:
 creation_time : 2018-01-31 22:40:10
 handler_name : Core Media Video
Input #3, mov,mp4,m4a,3gp,3g2,mj2, from '/home/vidinflux/public_html/assets/user/736/video/Lines11.mp4':
 Metadata:
 major_brand : mp42
 minor_version : 1
 compatible_brands: mp41mp42isom
 creation_time : 2018-01-31 22:40:09
 Duration: 00:00:04.90, start: 0.103811, bitrate: 846 kb/s
 Stream #3:0(und): Video: h264 (Baseline) (avc1 / 0x31637661), yuv420p(tv, smpte170m/bt470bg/bt709), 1920x1080, 827 kb/s, SAR 1:1 DAR 16:9, 30 fps, 30 tbr, 90k tbn, 180k tbc (default)
 Metadata:
 creation_time : 2018-01-31 22:40:10
 handler_name : Core Media Video
[Parsed_setsar_9 @ 0x17c8ba0] num:den syntax is deprecated, please use num/den or named options instead
[Parsed_setsar_11 @ 0x17cd840] num:den syntax is deprecated, please use num/den or named options instead
Stream specifier ':a' in filtergraph description [0:v]trim=0:138,setpts=PTS-STARTPTS[v0];[0:a]atrim=0:138,asetpts=PTS-STARTPTS[a0];[v0]scale='gte(iw/ih\,600/480)*600+lt(iw/ih\,600/480)*((480*iw)/ih):lte(iw/ih\,600/480)*480+gt(iw/ih\,600/480)*((600*ih)/iw)',pad='600:480:(600-gte(iw/ih\,600/480)*600-lt(iw/ih\,600/480)*((480*iw)/ih))/2:(480-lte(iw/ih\,600/480)*480-gt(iw/ih\,600/480)*((600*ih)/iw))/2:black'[x];[1:v]scale=600:480[y];[x][y]overlay=0:0[z];[2:v]scale=600:480,setsar=1:1[x0];[3:v]scale=600:480,setsar=1:1[x1];[x0][2:a][z][a0][x1][3:a]concat=n=3:v=1:a=1[v][a] matches no streams.


-
Why does ffmpeg report different durations ?
18 mai 2012, par kenitechSource videos : http://www.artworknotavailable.com/tmp/ffmpegtest
Quicktime Pro 7.7.1 Inspector (Win 7) reports the following for the file 2398.mov
4.19MB
H.264
Movie FPS : 23.98
Data Rate : 2.35 mbits/Sec
Duration 14:97ffmpeg reports the following (see full ffmpeg version info at bottom of post)
ffmpeg -i 2398.mov
Seems stream 1 codec frame rate differs from container frame rate : 47952.00 (47952/1) -> >23.98 (2997/125)
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '2398.mov' :
Metadata :
major_brand : qtminor_version : 537199360
compatible_brands : qt
Duration : 00:00:15.97, start : 0.-963005, bitrate : 2210 kb/s
Stream #0.0(eng) : Audio : aac, 48000 Hz, stereo, s16, 152 kb/s
Stream #0.1(eng) : Video : h264, yuv420p, 848x480, 2060 kb/s, 23.98 fps, 23.98 tbr, 23976 tbn, 47952 tbcOne second longer than what Quicktime reports.
As an experiment I exported this file from Quicktime Pro using the following settings :
Frame Rate : Current
Key Frames : Every 24 frames
Frame Reordering On
Quality : High
Encoding Best
Data Rate : Automatic
Optimized for Download
Output file : qtime-export-2398.movQuicktime Inspector reports :
5.62 MB
H.264
Movie FPS : 23.98
Data Rate : 3.15 mbits/Sec
Duration 14:97ffmpeg now reports :
ffmpeg -i qtime-export-2398.mov
Seems stream 1 codec frame rate differs from container frame rate : 1200.00 (1200/1) -> 23.98 (24000/1001)
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'qtime-export-2398.mov' :
Metadata :
major_brand : qt
minor_version : 537199360
compatible_brands : qt
Duration : 00:00:14.96, start : 0.000000, bitrate : 3153 kb/s
Stream #0.0(eng) : Audio : pcm_s16le, 44100 Hz, 2 channels, s16, 1411 kb/s
Stream #0.1(eng) : Video : h264, yuv420p, 678x384, 1738 kb/s, 23.98 fps, 23.98 tbr, 600 tbn, 1200 tbcffmpeg's report on duration went from 15.97 to 14.96 (I can live with .1)
Is this duration calculated from the bitrate ?
I need to accurately report the duration of uploaded videos as well as convert them to FLV. Can somebody tell me what is going on here and how I might get around this ?
ffmpeg info below. I've tried this on 2 completely different installs/versions of ffmpeg. Same result.
FFmpeg version 0.6.5, Copyright (c) 2000-2010 the FFmpeg developers
built on Jan 29 2012 23:55:02 with gcc 4.1.2 20080704 (Red Hat 4.1.2-51)
configuration : —prefix=/usr —libdir=/usr/lib64 —shlibdir=/usr/lib64 —mandir=/usr/share/man —incdir=/usr/include —disable-avisynth —extra-cflags='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector —param=ssp-buffer-size=4 -m64 -mtune=generic -fPIC' —enable-avfilter —enable-avfilter-lavf —enable-libdirac —enable-libfaac —enable-libfaad —enable-libfaadbin —enable-libgsm —enable-libmp3lame —enable-libopencore-amrnb —enable-libopencore-amrwb —enable-libx264 —enable-gpl —enable-nonfree —enable-postproc —enable-pthreads —enable-shared —enable-swscale —enable-vdpau —enable-version3 —enable-x11grab
libavutil 50.15. 1 / 50.15. 1
libavcodec 52.72. 2 / 52.72. 2
libavformat 52.64. 2 / 52.64. 2
libavdevice 52. 2. 0 / 52. 2. 0
libavfilter 1.19. 0 / 1.19. 0
libswscale 0.11. 0 / 0.11. 0
libpostproc 51. 2. 0 / 51. 2. 0
FFmpeg 0.6.5
libavutil 50.15. 1 / 50.15. 1
libavcodec 52.72. 2 / 52.72. 2
libavformat 52.64. 2 / 52.64. 2
libavdevice 52. 2. 0 / 52. 2. 0
libavfilter 1.19. 0 / 1.19. 0
libswscale 0.11. 0 / 0.11. 0
libpostproc 51. 2. 0 / 51. 2. 0
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