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Sur d’autres sites (14752)

  • 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<avpacket>::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, &amp;n);
    
    av_packet_unref(&amp;n);
    
}
    

    
ret = av_write_trailer(outputFormatCtx);
    
</avpacket>

    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.

  • Does this FFMPEG command create videos compatible with ABR playback on video.js player ?

    16 mars 2018, par alchemical

    We’re working on a site that will allow users to upload videos. It then encodes these videos into 4 bitrates. The initial version just lets the user manually select which of the 4 version they would like to play. However, the final version should allow for adaptive bitrate ABR using video.js player. Ideally, we should not need to re-encode the videos again for them to stream with ABR.

    I’m trying to understand if the current FFMPEG statement will support ABR :

    -i \"0\" -i \"1\" -threads 5 -filter_complex \"
    [0:v]scale=-2 :2[bg] ;[1:v]scale=-2:40*2/1080[watermark_scaled] ;[bg]
    [watermark_scaled]overlay=x=main_w-overlay_w-(10*
    2/1080):10*2/1080\" -acodec copy -vcodec libx264 -b:v
    3 \"4\"

  • ffmpeg : concat and encode with one command

    15 mars 2018, par Massimo Vantaggio

    I have a script that automates encode and concat a series of input video files.
    I’m trying to get encode and concat in a single command.

    At the moment it does not work causing immense empty pauses in the final video output.

    I would like to get the result with concat demux instead of concat protocol because it is much harder to automate in a script

    Do you know if it is possible to archive this result with concat demux ?
    Thanks a lot !

    Massimo

    ENCODE / CONCAT 1080p

    for f in ./*.mp4; do echo "file '$f'" >> list.txt; done
    

    
ffmpeg -f concat -safe 0 -y -i list.txt -i ../logo/logo.png -c:a aac -b:a 384k -ar 48000 -ac 2 -af aresample=async=1000 -c:v libx264 -x264opts keyint=50:min-keyint=50:no-scenecut -bf 0 -r 25 -b:v 4800k -maxrate 4800k -bufsize 3000k -profile:v main -crf 22 -filter_complex "[0:v][1:v]overlay=main_w-overlay_w-10:10,scale=1920:1080,setsar=1" ../buffer/1080set.mp4

    It seems to add long pause at low frame-rate :

    [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fb03f05e600] Auto-inserting h264_mp4toannexb bitstream filter

    frame= 9745 fps= 13 q=27.0 size= 186368kB time=00:18:52.56 bitrate=1348.0kbits

    frame= 9745 fps= 13 q=27.0 size= 186368kB time=00:18:56.57 bitrate=1343.3kbits/

    frame= 9745 fps= 13 q=27.0 size= 186368kB time=00:19:00.65 bitrate=1338.5kbits/

    frame= 9745 fps= 13 q=27.0 size= 186368kB time=00:19:02.29 bitrate=1336.5kbits/

    More than 1000 frames duplicated

    Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '1.mp4':
    
  Metadata:
    
    major_brand     : mp42
    
    minor_version   : 512
    
    compatible_brands: isomiso2avc1mp41
    
    creation_time   : 2016-02-27T22:25:49.000000Z
    
    encoder         : HandBrake 0.10.5 2016021100
    
  Duration: 00:06:29.87, start: 0.000000, bitrate: 3447 kb/s
    
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 768x432, 3282 kb/s, 25 fps, 25 tbr, 90k tbn, 180k tbc (default)
    
    Metadata:
    
      creation_time   : 2016-02-27T22:25:49.000000Z
    
      handler_name    : VideoHandler
    
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 159 kb/s (default)
    
    Metadata:
    
      creation_time   : 2016-02-27T22:25:49.000000Z
    
      handler_name    : Stereo
    

    
Input #1, mov,mp4,m4a,3gp,3g2,mj2, from '2.mp4':
    
  Metadata:
    
    major_brand     : M4V 
    
    minor_version   : 1
    
    compatible_brands: M4V mp42isom
    
    creation_time   : 2016-02-27T18:52:37.000000Z
    
  Duration: 00:07:16.93, start: 0.000000, bitrate: 1184 kb/s
    
    Stream #1:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, smpte170m), 768x432, 991 kb/s, 25 fps, 25 tbr, 25k tbn, 50 tbc (default)
    
    Metadata:
    
      creation_time   : 2016-02-27T18:52:37.000000Z
    
      handler_name    : Mainconcept MP4 Video Media Handler
    
      encoder         : AVC Coding
    
    Stream #1:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 189 kb/s (default)
    
    Metadata:
    
      creation_time   : 2016-02-27T18:52:37.000000Z
    
      handler_name    : Mainconcept MP4 Sound Media Handler
    

    
Input #2, mov,mp4,m4a,3gp,3g2,mj2, from '3.mp4':
    
  Metadata:
    
    major_brand     : mp42
    
    minor_version   : 0
    
    compatible_brands: mp42mp41
    
    creation_time   : 2017-06-27T17:58:17.000000Z
    
  Duration: 00:05:05.05, start: 0.000000, bitrate: 2622 kb/s
    
    Stream #2:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, smpte170m), 768x432, 2301 kb/s, 25 fps, 25 tbr, 25k tbn, 50 tbc (default)
    
    Metadata:
    
      creation_time   : 2017-06-27T17:58:17.000000Z
    
      handler_name    : Alias Data Handler
    
      encoder         : AVC Coding
    
    Stream #2:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 317 kb/s (default)
    
    Metadata:
    
      creation_time   : 2017-06-27T17:58:17.000000Z
    
      handler_name    : Alias Data Handler
    

    
Input #3, mov,mp4,m4a,3gp,3g2,mj2, from '4.mp4':
    
  Metadata:
    
    major_brand     : mp42
    
    minor_version   : 0
    
    compatible_brands: mp42mp41
    
    creation_time   : 2017-06-27T17:53:32.000000Z
    
  Duration: 00:06:47.36, start: 0.000000, bitrate: 3144 kb/s
    
    Stream #3:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, smpte170m), 768x432, 2819 kb/s, 25 fps, 25 tbr, 25k tbn, 50 tbc (default)
    
    Metadata:
    
      creation_time   : 2017-06-27T17:53:32.000000Z
    
      handler_name    : Alias Data Handler
    
      encoder         : AVC Coding
    
    Stream #3:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 317 kb/s (default)
    
    Metadata:
    
      creation_time   : 2017-06-27T17:53:32.000000Z
    
      handler_name    : Alias Data Handler

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