Ffmpeg pts timestamp. dts and pts, and maybe a few other things I can't remember.

Ffmpeg pts timestamp 25*PTS - quadruple the speed; setpts=2. For bash you need to use bc to evaluate expressions with decimals, but in zsh -ss 00:00:$[$(ffnearest input. So I calculated the DTS using current time information. With ffprobe it is like following. 5 seconds from the keyframe's actual timestamp does the trick. 9k次。本文围绕FFmpeg展开，介绍了每帧图像的pts用于多路流同步。阐述了时间基转换及相关函数，列举常用时间戳类型，解释pts初始为负的原因。还讲述推流时rtcp、rtp时间戳的编码，以及ffmpeg rtsp、rtp解码流程和pts的计算方法，分多路和单路情况。 PTS/DTS issues are my primary source of anger when dealing with video. ffmpeg 4. About August 15, 2018 · ffmpeg 音画同步 时间戳 pts ffmpeg中时间戳调整参数setpts PTS（Presentation Time Stamp）：即显示时间戳，这个时间戳用来告诉播放器该在什么时候显示这一帧的数据。 文章浏览阅读2. ts When examining the output1. mp4 While the difference in the end timestamp is only 0. 2666666666666666:end=4. See here. Fortunately, FFMpeg supplies us with a "best effort" timestamp, which you can get via, av_frame_get_best_effort_timestamp() I'm not able to display current timestamp like described in this post using text='%{pts\:hms}'. It is used to synchronize the playback of different media streams and ensure that they are presented in the correct order. user3533414. mp4 -select_streams v -show_entries frame=coded_picture_number,pkt_pts_time -of csv=p=0:nk=1 -v 0 . 000000 duration_ts=N/A duration=N/A bit_rate=N/A The generated file loogs like this : Video : start_pts=133508 start_time=1. ts -vf showinfo reveals that start timestamp under pts_time is not equal to zero. 435. -fps_mode passthrough - Each frame is passed with its timestamp from the demuxer to the muxer (prevents frame duplication and dropping). frame. 5. 265 -c:v copy video. For what it is worth, the DTS time seems to be correct. There is not much documentation, but I think that in newer versions of FFmpeg AVFrame::pkt_pts was declared deprecated, so ffprobe doesn't show 'pkt_pts_time' entries. So, in this case, our ffmpeg -i 0. h264 -vcodec copy output. 5*PTS - double the speed; setpts=0. webm There is a gmtime option for pts described in the documentation: > pts > The timestamp of the current frame. ts -vf "select=gte(n\, [FRAME_INDEX])" -show_entries frame=pkt_pts_time -v quiet -of csv="p=0" -stats -y output. 8k次，点赞3次，收藏14次。本文详细介绍了FFmpeg中PTS(time stamp)的计算方法及转换流程，包括有输入流地址和无输入流地址两种情况下的具体实现步骤。重点讨论了自变量frame_index的使用、时基转换函数av_rescale_q的应用以及延时处理等关键技术点。 这就是pts的转换。 根据pts来计算一桢在整个视频中的时间位置： timestamp(秒) = pts * av_q2d(st->time_base) duration和pts单位一样，duration表示当前帧的持续时间占多少格。或者理解是两帧的间隔时间是占多少格，一定要理解单位。 pts：格子数 av_q2d(st->time_base): 秒/格 The pts function will just use the stored timestamp. 48. Can ffmpeg do this? Providing additional details, When I run the above command i get around 100 JPEGs, I guess there is a 1 to 1 (or many to 1) correspondence between these JPEGS and frames of the video. How do I drawtext video playtime (“elapsed time”) on a video, with FFmpeg's --filter_complex option?. txt 文章浏览阅读1. 00 1 0. I have tried the following command ( I have replaced the [FRAME_INDEX] with 5), but it was nothing happend: ffmpeg -i 0. I packaged the raw video into mp4 file ffmpeg -i video. txt I would like to see the simple $ ffprobe -i input. Learned that the proper term for it is Burnt-in timecode, and found a post that was close. mp4 The code creates H264 synthetic video stream using ffmpeg, and then converts the stream The bug might be that the decoder is giving the first frame a dts of 1 instead of 0, while still keeping the pts at 0, and so later frames are also one timestamp late. /TB - Dividing by the timebase is used for converting the PTS to seconds. 0001, the first attempts results in 43 frames (duration of 1. av_q2d(st->time_base): 秒/格 I am applying av_scale_q(rtpTimeStamp, codec_timebase, stream_timebase) and setting the rescaled rtpTimeStamp as pts and dts values. DTS： DTS（Decoding TimeStamp）解码时间戳，在视频packet进行解码成frame的 文章浏览阅读2. Changing the timestamps prior to encoding is risky since ffmpeg's framerate conversion method uses timestamps to check sync drift and make decisions about dropping or duplicating frames. 3k次。该博客详细介绍了在ffmpeg接收rtsp流时如何设置pts和dts。pts的设置依赖于timestamp和rtcp的ntp时间，用于音视频同步，其变化值与帧率相关。dts的设置在无B帧时与pts相同，存在B帧时会缓存并选择特定的pts作为dts。 What is a Timestamp (PTS)? A timestamp (PTS) is a value that represents the presentation time of a media sample, such as a video frame or an audio sample. Looking around I found a formula for h264 streams ( c++ - ffmpeg::avcodec_encode_video setting PTS h264 - Stack Overflow ): Question. # Extract the H264 stream from the source file to a raw H264 stream ffmpeg -i source. Since they don't have a pts, they are assigned the same value as the dts. At least not for the hms format. Today, it is a totally different program, and improvements in the ffmpeg libraries (and in ffplay. According to the documentation:. 1w次，点赞11次，收藏69次。本文深入探讨了视频编码中的I帧、P帧和B帧概念，以及在解码过程中的作用。同时，详细阐述了DTS和PTS在视频流中的差异，以及FFmpeg中时间基和时间戳的处理。内容涵盖视频帧类型、时间戳转换、FFmpeg内部时间处理和转封装、转码过程中的时间基转换等关键 PTS は必須の要素で、そのフレームが再生されるべき時間を表します。 DTS はオプショナルの要素で、そのフレームをデコードすべき時間を表します。 FFmpeg の ffprobe コマンドを使うと TS ファイルの各フレームの PTS を見ることができます。 At whatever precision. Default value is 1 I have a script to cut at exact times inserted in a text file; the timestamp of the cut point is identified overlaying the pts on every frame with drawtext filter, and/or exporting exact frame number as a pic and checking frame's timestamp with ffprobe, and/or with ffmpeg -i xxxx -ss [] (accurate seek). It is AVPacket's member pts. Frame pts_time 0 0. 200000,7 0. 7334,setpts=PTS-STARTPTS" -an output. 文章浏览阅读5. mkv The filter works by changing the presentation timestamp (PTS) of each video frame. ffmpeg -y -f lavfi -i testsrc=size=384x216 I am trying to extract the timestamps of mp4 video using ffmpeg. 有了上面 I/B/P帧的概念，我们再来理解 PTS/DTS 就非常容易了。PTS（Presentation TimeStamp）是渲染用的 时间戳 ，也就是说，我们的视频帧是按照 PTS 的时间戳来展示的。DTS（Decoding TimeStamp）解码时间戳，是用于视频解码的。 那为什么有了 PTS 还要有 av_read_frame() will give you a PTS (Presentation Time Stamp). Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. There are a lot of methods on superuser to obtain the timestamps of a frame in ffmpeg, however is it possible to get the absolute timestamp that is close to real time from a live video stream? ffmpeg rtp时间戳ffmpeg c 一、介绍在ffmpeg中，每帧都会存在一个pts用来表示该帧图像在视频流中的位置。而在多路流（比如视频、音频）时，往往需要进行多媒体的同步，使得画面和声音同步，这时便需要使用两者的pts来做同步。那么pts是如何计算得到的呢，如何使用它做 根据pts来计算一桢在整个视频中的时间位置： timestamp (秒) = pts * av_q2d(st->time_base) duration和pts单位一样，duration表示当前帧的持续时间占多少格。或者理解是两帧的间隔时间是占多少格。一定要理解单位。 pts：格子数 So, instead of recording a video as 25 fps, and thus implying that each frame should be drawn 0. h. c. Thus, we have to multiply them by 0. 08 3 0. ts -show_frames -select_streams v:0 -print_format flat | grep pkt_pts= frames. mkv -filter:v "setpts=0. I am extracting 1 frame per second using the following command: timestamp – Different PTS values in ffmpeg and MP4 CTS values obtained using ctts and stts – Stack Overflow. If a timestamp discontinuity is detected whose absolute value is greater than threshold, ffmpeg will drop the PTS/DTS timestamp value. Perhaps that value can help you decide when to stop reading. h264 # Force FFMPEG to regenerate the PTS values for the H264 stream ffmpeg -fflags +genpts -r 60 -i source-video. rtbufsize integer (input) Override teletext packet PTS and DTS values with the timestamps calculated from the PCR of the first program which the teletext stream is part of and is not discarded. 264 ffmpeg -r 10 -i test. ts using, ffplay -i output1. best_effort_timestamp, checking AVPacket. 264 -vcodec copy test. Eventually the problem was in PTS and DTS values, so lines 12-15 where added before av_interleaved_write_frame function: 1. mp4 -vf "setpts=PTS-STARTPTS" -c:a copy output. According to ffmpeg docs a frame_pts option should also be available that would use timestamps in the saved frame filenames (which would not be ideal either, as I would still have to parse filenames to get them, but it's an alternative), but I don't seem to get it to work in ffmpeg-python. mp4 I have downloaded from the internet Any pointers on how to get a pts timestamp and frame without loading the entire video file into memory? I'm able to iteratively get the frames from the Process video frame-by-frame using numpy section of the documentation, but I'm not able to Use the setpts (set presentation timestamp) video filter (-vf). ffmpeg extract single keyframe to image and get timestamp of keyframe. 5 and 1, respectively. /TB/1000 - Used for converting the PTS to milliseconds (assuming the numbers applies milliseconds). ffmpeg -i file1. 436. I can then renormalize on my computer (although the file seems to play fine without renormalization). You just need to make sure the value of -read_intervals, in seconds, is 这就是pts的转换。 根据pts来计算一桢在整个视频中的时间位置： timestamp(秒) = pts * av_q2d(st->time_base) duration和pts单位一样，duration表示当前帧的持续时间占多少格。或者理解是两帧的间隔时间是占多少格，一定 I notice that when I do this, the resulting . It's relative presentation time depends on the start_time of the file, for which use -show_entries The speed of a video stream can be changed by changing the presentation timestamp (PTS) of each video frame. 100 miliseconds is good enough for me. PTS: PTS（Presentation TimeStamp）是渲染用的时间戳，播放器会根据这个时间戳进行渲染播放. Can someone suggest the right syntax per this option? Oh, I see, then simply using ffmpeg -use_wallclock_as_timestamps 1 -i - -c:v copy out. Please help me how to set pts and dts values on the AVPacket, so as get a working webm file with proper meta info on it. hms stands for a formatted [-]HH:MM:SS. If you do a ffmpeg中常用的几个时间戳： rtcp_ntp_timestamp: 真实时间， 绝对时间，在网络传输时的时间基(1 << 32)， rtcp_timestamp: rtcp时间，一般会有一个base, 在网络传输时的时间基90000 rtp_timestamp: rtp时间，和rtcp_timestamp类似，网络时间基90000 Avpacket->pts: 通过如上计算得到，video 这就是pts的转换。 根据pts来计算一桢在整个视频中的时间位置： timestamp(秒) = pts * av_q2d(st->time_base) duration和pts单位一样，duration表示当前帧的持续时间占多少格。或者理解是两帧的间隔时间是占多少格。一定要理解单位。 pts：格子数 . mp4 PTS/DTS. -video_track_timescale 100000 - Set explicit Run. This is the command I used; ffmpeg -i & ffmpeg; timestamp; libx264; Share. I used a combination of methods: checking AVFrame. 280000,8 0. pkt_dts. So, instead of recording a video as 25 fps, I am trying to extract the timestamps of mp4 video using ffmpeg. Should work but several players (incl. av_q2d(st->time_base): 秒/格 The presentation timestamp (PTS) is a timestamp metadata field in an MPEG transport stream or MPEG program stream that is used to achieve synchronization of programs' separate elementary streams (for example Video, Audio, Subtitles) when presented to the viewer. The PTS is given in units related to a program's overall clock reference, either Program Clock Reference (PCR) or I am trying to mark a timestamp in a video using drawtext filter. 1. Some example values: setpts=0. DTS copied from the AVPacket that triggered returning this frame. 1. 4からはビットストリームフィルタでPTSを書き換えられるようになったので再エンコードコード不要で映像の再生速度を変更できる。 My input is a ts file. mp4" -show_frames -show_en I had fps issues when transcoding from avi to mp4(x264). I would like to embed the computer's local time in milliseconds into a stream using FFMPEG. I am trying to mux H264 encoded data and G711 PCM data into mov multimedia container. mp4 and then the command from the post above works just fine. 2进行分析 以下文档中有关音频的具体时间戳数据来自以下转码命令： . Share. 33x speed; setpts=0. pkt_pts=4205071050 And I need to pts_time=6. 文章浏览阅读7k次，点赞9次，收藏46次。ffmpeg中在不同是层（封装、编解码、数据）的采样率不同，为精确描述该其数值，使用结构AVRational来描述时基这一概念。一个时间戳在不同的时基下进行变化，获取 Options may be set by specifying -option value in the FFmpeg tools, Set max memory used for timestamp index (per stream). Quicktime) still show them as black. 50 seconds). Examples decode_audio. How to get frame number given a timestamp using ffmpeg. 04 2 0. This command will copy the audio stream and reset the video stream to start at timestamp 0. I'm also re-encoding the mp4 file for different bitrates. The same documentation: If the format is set to localtime or gmtime, a third argument may be supplied: a strftime() format string. I tried executing the following code, to check if it's a problem in my H264 stream: ffmpeg -f lavfi -i testsrc -t 3 -r 10 -pix_fmt yuv420p -c:v libx264 test. mp4 -vf "trim=start=3. You will have to modify the timestamp before the drawtext filter and restore the original value afterwards i. 433333 seconds), while the second one gives 45 frames (duration of 1. 有了PTS为什么还需要DTS DTS（解码时间戳）和PTS（显示时间戳）分别是解码器进行解码和显示帧时相对于SCR（系统参考）的时间戳。SCR可以理解为解码器应该开始从磁盘读取数据时的时间。 mpeg文件中的每一个包都有一个SCR时间戳并且这个时间戳就是读取这个数据包时的系统时间。通常情况下，解码器会在它开始读取mpeg流时 . My code - bool AudioVideoRecorder::WriteVideo(const unsigned char Because maybe the source video was generated by cutting a video, then ffmpeg can only cut on specific times, it cuts at a previous frame and tags the PTS as negative. – I came across this post from google trying to overlay time elapsed for my video. 5] works. 506000 means an absolute presentation timestamp of 6. mp4 media files. Example. command: ffprobe -v quiet -f lavfi -print_format json -i "movie=test. c, decode_video. pkt_pts=4205067450 frames. ) I decided to dig a little in the source to understand what's happening. The advisable way to do this is using the option -output_ts_offset N where N is in seconds. 音频时间戳设置 以下代码基于FFmpeg n5. c itself) have caused some strategies to change. mp4 -map 0:v -vcodec copy -bsf:v h264_mp4toannexb source-video. mp4. 506 seconds. But I'm still curious if it is possible to do FFMPEG with HLS PTS Discontinuity Support - Live HLS transmux/transcode to RTMP or MPEG-TS with PTS reclocking - jjustman/ffmpeg-hls-pts-discontinuity-reclock ffmpeg -i input. In libimxvpuapi encoded_frame->pts just copies raw_frame->pts, so I guess the raw_frame->pts needs to be calculated by the application. PTS copied from the AVPacket that was decoded to produce this frame. 483422 duration_ts=450449 duration=5. c, decode_filter_video. mp4 -c:v libx265 -x265-params crf=25 -c:a copy output1. > > The first argument is the format of the timestamp; FFmpeg is the leading multimedia framework, able to decode, encode, transcode, mux, demux, stream, filter and play pretty much anything that humans and machines have created. The conversion command looks like this: ffmpeg -i file1. 240000,6 0. Made some changes and was able to get the timecode If the container allows it, you can start at non-zero PTS. 04 seconds apart, they store a timestamp for each frame e. I have been studying PTS values in . 这就是pts的转换。 根据pts来计算一桢在整个视频中的时间位置： timestamp(秒) = pts * av_q2d(st->time_base) duration和pts单位一样，duration表示当前帧的持续时间占多少格。或者理解是两帧的间隔时间是占多少格。一定要理解单位。 pts：格子数 av_q2d(st->time_base): 秒/格 First off, Use int64_t pts = av_frame_get_best_effort_timestamp(pFrame) to get the pts. The easiest way to do this is convert everything to AV_TIME_BASE_Q. Using this my rendered output looks like this: Just an info. ; Elapsed 3 seconds since I'm using ffmpeg to generate a MPEG-TS stream using the following command. And I'm trying to use FFmpeg to extract the timestamp (PTS) from the specific frame index. deprecated and will stop working in the future. FFmpeg easily marks timestamps based on localtime, gmtime or even PTS. This can be done via two methods: using the setpts To extract a specific frame index using FFmpeg's timestamp (PTS), you can use the following command: In this command, input. mp4 -vcodec copy -acodec copy -f mpegts file1. mmm timestamp with millisecond accuracy. c, and transcode. How can I overlay the captured timestamp onto a video using ffmpeg in YYYY-MM-DD HH:MM:SS format? 3 Using FFmpeg via PowerShell - Correct use of dashes and quotes in arguments [mp4 @ 000001fe0193b700] Application provided duration: 2585263321 / timestamp: 6303355764 is out of range for mov/mp4 format [mp4 @ 000001fe0193b700] pts has no value [mp4 @ 000001fe0193b700] Application provided duration: 2585443321 / timestamp: 6303535765 is out of range for mov/mp4 format [mp4 @ 000001fe0193b700] pts has no value I'm trying to split an mp4 file into segments and each segment should start with near to zero a/v pts. These videos will play back fine in ffplay, mpv, etc but stutter an extreme amount when playing through a chromium/safari. The values are not the DTS/PTS you expect, note the pkt_ prefix. But I don't know how to fix it here is my ffmpeg command (transcode to 250k bps) ===== ffmpeg -y -i sample-03. /ffmpeg_g -rw 2. ; Elapsed 2 seconds since the video started: the video displays 00:02 / 02:30. A remuxing using FFMPEGを使うことで、動画に文字入れができることを以前紹介しました。 今回はこれを応用して、下記の画像のよ 「text=”###”」の箇所に、表示したいテキストを入力します。今回は「%{pts\\:hms}」を挿入することでタイムスタンプを表示することができ My issue is that the start_pts is not 0 even if i use -copyts The original stremas looks like this : Audio & Video : start_pts=0 start_time=0. Hot Network Questions I am using ffmpeg version: ffmpeg-3. -r 1000 - set the framerate The decoding timestamp tells us when we need to decode something, and the presentation time stamp tells us when we need to display something. Visit Stack Exchange pts_time is the equivalent for pkt_pts_time. Definition at line 248 of file avutil. mkv -r 1000 -f image2 -frame_pts 1 %d. PTS for video stream can be extracted from ffmpeg CLI using. 66*PTS - roughly 1. I would like to know the timestamp of the frame that was output as a JPEG image 'i'. Extracting a Specific Frame Index using FFmpeg's Timestamp (PTS) When we get a packet from av_read_frame(), it will contain the PTS and DTS values for the information inside that packet. . 004989 Audio : Undefined timestamp value. mp4 is the name of the input video file, Modern containers govern the time component of presentation of video (and audio) frames using timestamps, rather than framerate. mp4 | tail -1 This will print values in the form of 118231200|3600 where the first value is the pts and the second the duration of the last packet of the video stream. e. ffmpeg -vsync 0 -i video. Stack Exchange Network. DTS： DTS（Decoding TimeStamp）解码时间戳，在视频packet进行解码成frame的时候会使用到. For example, if there are two succesive frames shown at timestamps 1 and 2, and you want to speed up the video, those timestamps need to become 0. AVFormatContext* When I use ffmpeg to transcode one of the media segment (ex 800k bps to 200k bps) I guess it's the ffmpeg reset the PTS(presentation timestamp) of segment. 要想解决时间同步问题就必须要了解ffmpeg中的PTS和DTS到底是什么. When I first made this tutorial, all of my syncing code was pulled from ffplay. By default, YYYY-MM-DD ffmpeg -i input. However, I want to assign a reference time (start time) for the timestamp in order to represent the time the video was recorded (not encoded). jpg-vsync 0 - Each frame is passed with its timestamp from the demuxer to the muxer. 3. mkv 28)-0. ts files always begin at pts = 126000 pts_time = 1. pts = av_rescale_q ( pts, formatCtx->streams[videoStream]->time_base, AV_TIME_BASE_Q ); In this format, pts is in nanoseconds. setpts=PTS*10,drawtext=,setpts=PTS/10 where the factor 10 is the ratio of realtime between frames and their display interval in the timelapse video. Improve this question. Fix The timestamp correction enabled by this option is only applied to input formats not accepting timestamp discontinuity (for which the AVFMT_TS_DISCONT flag is not enabled). asked Nov 16, 2020 at 16:47. dts and pts, and maybe a few other things I can't remember. Alternatively, you can use the expression “PTS-STARTPTS+0” which will add 0 to the timestamps, effectively resetting the timestamps to 0. mkv would do most of the job, and my Android tablet can actually do this fast enough. I have found the method used by dranger's tutorial not to be sufficient. g. 4000 I've used 'ffprobe -show_packets' on both the input and the output to examine the PTS and PTS_TIME. 5*PTS" output. ffmpeg -hide_banner -i -vf "showinfo" -f null - For a sample . Second you must make sure both streams you are syncing use the same time base. The overall start_time of the program is calculated by the using the presentation time stamp(PTS) of each individual stream in the file. I am creating AVPacket from encoded data and initially the PTS and DTS value of video/audio frames is equivalent to AV_NOPTS_VALUE. 320000,5 where presented frame n is on line n (annoyingly, telling ffmpeg to seek to exactly to the timestamp of the keyframe seems to make ffmpeg exclude that keyframe in the output, but subtracting 0. it shows 1. Assuming I have a video whose duration is 150 seconds: Elapsed 1 second since the video started: the video displays 00:01 / 02:30. If my tablet crashes during recording, the MKV file would still be readable with the correct Is there an easy way to do this using the ffmpeg libraries? I've looked at av_frame_get_best_effort_timestamp as well as codec_context->time_base, but that seems to give the answers in seconds since the beginning of the video, and I don't necessarily know when the video started. ffmpeg -i input. EDIT : Which ffmpeg command should I use to extract each frame number associated with its timestamp (time in ms from the starting of the video) ? ffprobe video. 首先介绍下概念： PTS：Presentation Time Stamp。PTS主要用于度量解码后的视频帧什么时候被显示出来 DTS：Decode Time Stamp。DTS主要是标识读入内存中的bit流在什么时候开始送入解码器中进行解码 也就是pts反映帧什么时候开始显示，dts反映数据流什么时候开始解码 怎么理解这里的“什么时候”呢？ 【该文章，是属于ffmpeg的细枝末节，会写的比较啰嗦】 【不同的转码环境，会有代码流程的不同】 首先普及下： 时间戳，DTS(decoding time stamp)，PTS(presention time stamp)，CTS（current time stamp）。ffmepg中的时间戳，是以微秒为单位，关乎timebase变量，它是作为dts、pts的时间基准粒度，数 uint64_t v; // this is a 64bit integer, lowest 36 bits contain a timestamp with markers uint64_t pts = 0; pts |= (v >> 3) & (0x0007 << 30); // top 3 bits, shifted left by 3, other bits zeroed out pts |= (v >> 2) & (0x7fff << 15); // middle 15 bits pts |= (v >> 1) & (0x7fff << 0); // bottom 15 bits // pts now has correct timestamp without Previous message: [FFmpeg-user] dshow: Multi channel Video Capture Cards for FFmpeg Next message: [FFmpeg-user] box=1" -c:a copy out. mp4" I am attempting to extract frames with their timestamps from videos using the command line, but I am struggling to relate both the output of the showinfo filter to the actual frames outputted by the command, and the corresponding output file names from the -frame_pts option. And there's no way to customize this timestamp format. It can take up to three arguments. Note that PTS and DTS are not equivalent. c CAVEAT. But what we really want is the PTS of our newly decoded raw frame, so we know when to display it. 12 How ffmpeg knows, what should be set with the resulting number of expression 'PTS-2/TB' or '0. PTS/DTS（时间戳） 要想解决时间同步问题就必须要了解ffmpeg中的PTS和DTS到底是什么. 46*PTS'? And why video playing speed and offsetting is called presentation timestamp? I barely can understand, how presentation timestamp can be interpreted as offset, okay, but what's the deal with the speed? It took me a while to narrow down the issue but I think it is due to the pts/pts_timestamp having an incorrect value. pkt_pts. 有SR包时，计算一个RTP包的pts实际上是三段相加，第一段是首个RTCP SR包的timestamp减去首个RTP包的timestamp，第二段是最后一个SR包的NTP timestamp减去首个SR包的NTP timestamp，第三段是要计算的这个RTP包的timestamp减去最后一个SR包中的timestamp. Usually reported by demuxer that work on containers that do not provide either pts or dts. I can embed the local time in seconds using drawtext like so: ffmpeg -i &lt;input&gt; -vf "drawtext=tex I am a bit new to ffmpeg, apart from that I have a question. 0*PTS - half the speed; For example, to double the speed of a 这就是pts的转换。 根据pts来计算一桢在整个视频中的时间位置： timestamp(秒) = pts * av_q2d(st->time_base) duration和pts单位一样，duration表示当前帧的持续时间占多少格。或者理解是两帧的间隔时间是占多少格。一定要理解单位。 pts：格子数. ffprobe -v 0 -show_entries packet=pts,duration -of compact=p=0:nk=1 -read_intervals 999999 -select_streams v video. My guess is my way of setting pts and dts is wrong. Follow edited Nov 16, 2020 at 16:56. The argument to the setpts filter is a formula for how to set the timestamp. 2-win64. ts -f mpegts -acodec libfaac -ar 48000 -ab 64k -vcodec libx264 -b 250k Tutorial 05: Synching Video Code: tutorial05. jfhq qpwuthe xrgoxxg zii fuzj hmki xokqggk joyal fwg wzann cilay rfvwxll ysgubgh mlwuvi dwnf