Newest 'ffmpeg' Questions - Stack Overflow

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  • How to automatically cut video based on motion-less scenes ?

    18 mars 2018, par user1202136

    I recently recorded a very long video (45 minutes) using the H264 codec, with I-frames every 30 seconds.

    I would like to cut this video in smaller parts separated by "quiet" periods, i.e., parts of the video where no motion is detected for 5 seconds. I would also prefer to not re-encode the video, but rather cut around the I-frames.

    Is there a tool to automatically achieve this?

  • Ignore streams when finding stream info

    17 mars 2018, par CSNewman

    I’m trying to speed up the start of ffmpeg when processing my live stream, and have narrowed down the issue to the ‘avformat_find_stream_info’ function. The source I’m trying to process seems to have a number of streams that ffmpeg is unable to determine what they are and therefore spends a while trying to find information about them (The entire analyse window). I know ahead of time that I only want to find information about stream #0:0 and #0:1, and I will be disregarding the other streams anyways.

    I managed to work around this using the API by setting the number of streams before the find information call and then restoring the value afterwards.

    inputContext->nb_streams = (uint) 2;
if (ffmpeg.avformat_find_stream_info(inputContext, null) < 0)
{
    throw new InvalidOperationException("Could not read stream information.");
}
inputContext->nb_streams = oldSize;

    However, I would prefer to use the CLI interface of ffmpeg.

    My current command

    ffmpeg -find_stream_info false -i http://192.168.1.112:5004/auto/v1 -c copy -map 0:v:0 -map 0:a:0 -ignore_unknown   -f hls -hls_flags delete_segments  -segment_list playlist.m3u8 -segment_list_type hls -segment_list_size 10 -segment_list_flags +live -segment_time 10 -f segment stream%%05d.ts

    Giving the following input (Unneeded logging removed)

    [mpeg2video @ 000001ce79423440] Invalid frame dimensions 0x0.
    Last message repeated 9 times
[mpegts @ 000001ce7941b740] Could not find codec parameters for stream 5 (Unknown: none ([11][0][0][0] / 0x000B)): unknown codec
Consider increasing the value for the 'analyzeduration' and 'probesize' options
[mpegts @ 000001ce7941b740] Could not find codec parameters for stream 6 (Unknown: none ([11][0][0][0] / 0x000B)): unknown codec
Consider increasing the value for the 'analyzeduration' and 'probesize' options
[mpegts @ 000001ce7941b740] Could not find codec parameters for stream 7 
(Unknown: none ([5][0][0][0] / 0x0005)): unknown codec
Consider increasing the value for the 'analyzeduration' and 'probesize' options
[mpegts @ 000001ce7941b740] Could not find codec parameters for stream 8 
(Unknown: none ([5][0][0][0] / 0x0005)): unknown codec
Consider increasing the value for the 'analyzeduration' and 'probesize' options
Input #0, mpegts, from 'http://192.168.1.112:5004/auto/v1':
  Duration: N/A, start: 91296.182311, bitrate: N/A
  Program 4165
    Stream #0:0[0x65]: Video: mpeg2video (Main) ([2][0][0][0] / 0x0002), yuv420p(tv, top first), 704x576 [SAR 16:11 DAR 16:9], 25 fps, 25 tbr, 90k tbn, 50 tbc
    Stream #0:1[0x66](eng): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, s16p, 256 kb/s
    Stream #0:2[0x6a](eng): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, mono, s16p, 64 kb/s (visual impaired) (dependent)
    Stream #0:3[0x69](eng): Subtitle: dvb_subtitle ([6][0][0][0] / 0x0006)
    Stream #0:4[0x98]: Audio: mp2 ([6][0][0][0] / 0x0006), 48000 Hz, stereo, s16p, 128 kb/s
    Stream #0:5[0x1c21]: Unknown: none ([11][0][0][0] / 0x000B)
    Stream #0:6[0x1c33]: Unknown: none ([11][0][0][0] / 0x000B)
    Stream #0:7[0x1bbf]: Unknown: none ([5][0][0][0] / 0x0005)
    Stream #0:8[0x1bc1]: Unknown: none ([5][0][0][0] / 0x0005)

    I’m unsure if there’s a way to achieve the same functionality with the CLI, however I’m open changing how my setup works.

    One idea that I considered was running two ffmpeg instances, one to strip the unneeded streams (and not find the stream info) and then have another that takes that stripped stream and performs the rest of the functionality.

    Any insight here would be grateful, thanks in advance.

  • Piping ppm files to ffmpeg to create movie in c++

    17 mars 2018, par chasep255

    I want to create a movie of a zoom on the Mandelbrot set. To do this I want to create image data in the ppm format and then pipe it into ffmpeg using popen. The following command works if I first save the ppm to my disc and then run ffmpeg through the terminal.

    ffmpeg -i out.ppm -r 1/5 out.mp4

    Here is what I am trying to do in code.

    FILE* p = popen("ffmpeg -i /dev/stdin -r 1/5 out.mp4", "w");
ppm_pipe(p, pix_buffers[0], w, h);
fclose(p);
...
void ppm_pipe(FILE* f, unsigned char* pix, int w, int h)
{
    assert(fprintf(f, "P6 %d %d 255\n", w, h) > 0);
    size_t sz = 3 * (size_t)w * (size_t)h;
    assert(fwrite(pix, 1, sz, f) == sz);
}

    I get the following error message.

    ffmpeg version 2.5.8-0ubuntu0.15.04.1 Copyright (c) 2000-2015 the FFmpeg developers
  built with gcc 4.9.2 (Ubuntu 4.9.2-10ubuntu13)
  configuration: --prefix=/usr --extra-version=0ubuntu0.15.04.1 --build-suffix=-ffmpeg --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --shlibdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --enable-shared --disable-stripping --enable-avresample --enable-avisynth --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libschroedinger --enable-libshine --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libwavpack --enable-libwebp --enable-libxvid --enable-opengl --enable-x11grab --enable-libdc1394 --enable-libiec61883 --enable-libzvbi --enable-libzmq --enable-frei0r --enable-libvpx --enable-libx264 --enable-libsoxr --enable-gnutls --enable-openal --enable-libopencv --enable-librtmp --enable-libx265
  libavutil      54. 15.100 / 54. 15.100
  libavcodec     56. 13.100 / 56. 13.100
  libavformat    56. 15.102 / 56. 15.102
  libavdevice    56.  3.100 / 56.  3.100
  libavfilter     5.  2.103 /  5.  2.103
  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
/dev/stdin: Invalid data found when processing input

  • JW Player fails with error with wma files : Task Queue failed at step 5

    17 mars 2018, par Sabeena

    I have a JW Player which plays MP3 files but with WMA files it gives the error:

    Task Queue failed at step 5: Playlist could not be loaded: Playlist file did not contain a valid playlist

    I thought of two reasons:

    1. There is no support for WMA but please confirm me this.
    2. Somewhere I need to setup the type of file I am using in this player.

    If WMA not supported in JW Player how can I play WMA and MP3 files in my website?

    Is ffmpeg needed to convert WMA to MP3 while uploading?

  • Adjust PTS and DTS before mp4 video creation

    17 mars 2018, par Cristiano

    I'm retrieving raw h264 compressed frames from usb camera to create an mp4 video. This is my simple code:

    for(int i = 0; i<120;i++)
{
    AVPacket pkt;
    av_init_packet(&pkt);
    ret = av_read_frame(inputFormatCtx, &pkt);

    pkt.pts = pkt.dts = i;
    pkt.pts = av_rescale_q(pkt.pts, inputStream->time_base, outputStream->time_base);
    pkt.dts = av_rescale_q(pkt.dts, inputStream->time_base, outputStream->time_base);

    ret = av_interleaved_write_frame(outputFormatCtx, &pkt);
    av_packet_unref(&pkt);
} 
ret = av_write_trailer(outputFormatCtx);

    This works well. Now I would like to store these AVPackets to create the video in a second moment. I changed my code in this way

    for(int i = 0; i<120;i++){
AVPacket pkt;
av_init_packet(&pkt);
ret = av_read_frame(inputFormatCtx, &pkt);
packets.push_back(pkt);
} 

vector::reverse_iterator it;
int j = 0;
for(it = packets.rbegin(); it != packets.rend(); it++){
    AVPacket n = (*it);
    n.pts = n.dts = j;
    j++;
    n.pts = av_rescale_q(n.pts, inputStream->time_base, outputStream->time_base);
    n.dts = av_rescale_q(n.dts, inputStream->time_base, outputStream->time_base); 
    ret = av_interleaved_write_frame(outputFormatCtx, &n);
    av_packet_unref(&n);
}

ret = av_write_trailer(outputFormatCtx);

    The resulting video is not so fluid and I used ffprobe to see more details. These are the first three frame generating with the first block of code.

    [FRAME]
media_type=video
stream_index=0
key_frame=1
pkt_pts=0
pkt_pts_time=0.000000
pkt_dts=0
pkt_dts_time=0.000000
best_effort_timestamp=0
best_effort_timestamp_time=0.000000
pkt_duration=512
pkt_duration_time=0.033333
pkt_pos=48
pkt_size=12974
width=1920
height=1080
pix_fmt=yuv420p
sample_aspect_ratio=N/A
pict_type=I
coded_picture_number=0
display_picture_number=0
interlaced_frame=0
top_field_first=0
repeat_pict=0
[/FRAME]
[FRAME]
media_type=video
stream_index=0
key_frame=0
pkt_pts=512
pkt_pts_time=0.033333
pkt_dts=512
pkt_dts_time=0.033333
best_effort_timestamp=512
best_effort_timestamp_time=0.033333
pkt_duration=512
pkt_duration_time=0.033333
pkt_pos=13022
pkt_size=473
width=1920
height=1080
pix_fmt=yuv420p
sample_aspect_ratio=N/A
pict_type=P
coded_picture_number=1
display_picture_number=0
interlaced_frame=0
top_field_first=0
repeat_pict=0
[/FRAME]
[FRAME]
media_type=video
stream_index=0
key_frame=0
pkt_pts=1024
pkt_pts_time=0.066667
pkt_dts=1024
pkt_dts_time=0.066667
best_effort_timestamp=1024
best_effort_timestamp_time=0.066667
pkt_duration=512
pkt_duration_time=0.033333
pkt_pos=13495
pkt_size=511
width=1920
height=1080
pix_fmt=yuv420p
sample_aspect_ratio=N/A
pict_type=P
coded_picture_number=2
display_picture_number=0
interlaced_frame=0
top_field_first=0
repeat_pict=0
[/FRAME]

    While these are the same frames created using the second block of code.

    [FRAME]
media_type=video
stream_index=0
key_frame=1
pkt_pts=14848
pkt_pts_time=0.966667
pkt_dts=14848
pkt_dts_time=0.966667
best_effort_timestamp=14848
best_effort_timestamp_time=0.966667
pkt_duration=512
pkt_duration_time=0.033333
pkt_pos=757791
pkt_size=65625
width=1920
height=1080
pix_fmt=yuv420p
sample_aspect_ratio=N/A
pict_type=I
coded_picture_number=58
display_picture_number=0
interlaced_frame=0
top_field_first=0
repeat_pict=0
[/FRAME]
[FRAME]
media_type=video
stream_index=0
key_frame=0
pkt_pts=15360
pkt_pts_time=1.000000
pkt_dts=15360
pkt_dts_time=1.000000
best_effort_timestamp=15360
best_effort_timestamp_time=1.000000
pkt_duration=512
pkt_duration_time=0.033333
pkt_pos=823416
pkt_size=29642
width=1920
height=1080
pix_fmt=yuv420p
sample_aspect_ratio=N/A
pict_type=P
coded_picture_number=60
display_picture_number=0
interlaced_frame=0
top_field_first=0
repeat_pict=0
[/FRAME]
[FRAME]
media_type=video
stream_index=0
key_frame=1
pkt_pts=30208
pkt_pts_time=1.966667
pkt_dts=30208
pkt_dts_time=1.966667
best_effort_timestamp=30208
best_effort_timestamp_time=1.966667
pkt_duration=512
pkt_duration_time=0.033333
pkt_pos=1546454
pkt_size=66021
width=1920
height=1080
pix_fmt=yuv420p
sample_aspect_ratio=N/A
pict_type=I
coded_picture_number=117
display_picture_number=0
interlaced_frame=0
top_field_first=0
repeat_pict=0
[/FRAME]

    I immediately noticed that pkt_pts_time and other fields are not starting from 0 and are not increasing linearly (respect to the 30 fps that I established). It is possible to obtain the same video writing the AVPackets in a second moment as I'm doing? Thank you.

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