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• Transcoding MPEG-1 to MPEG-H (H.265/HEVC)

  17 juin 2021, par Alexander Shukaev

  Transcoding MPEG-4 video to MPEG-H in order to reduce the size in half without losing perceivable quality is relatively easy with a 2-pass approach presented within FFMPEG documentation. The scheme that I've been using is to extract the bit_rate value from the original MPEG-4 video using ffprobe and then multiply that value by 4 / 10. Thus, that new lower value would be specified by -b:v and become the bit_rate value of the resulting MPEG-H video. This worked quite well for most of the videos, not only with MPEG-4, but also with QuickTime and Audio Video Interleave (AVI).

  


  However, now I stumbled across the issue with transcoding MPEG-1 video in such a way. Somehow, the resulting MPEG-H video is unacceptably larger than the original video by a hefty margin. A 200MB original video could easily result in 1.5GB transcoded video. When I looked for a reason for such ridiculous behavior, I found out that somehow the advertised bit_rate value in MPEG-1 videos is also ridiculously high. Take the following two videos as an example (output from ffprobe) :

  


  164MB                           15MB
[STREAM]                        [STREAM]
index=0                         index=1
codec_name=mpeg4                codec_name=mpeg1video
codec_long_name=MPEG-4 part 2   codec_long_name=MPEG-1 video
profile=Simple Profile          profile=unknown
codec_type=video                codec_type=video
codec_time_base=1/24            codec_time_base=1/25
codec_tag_string=mp4v           codec_tag_string=[0][0][0][0]
codec_tag=0x7634706d            codec_tag=0x0000
width=960                       width=640
height=540                      height=480
coded_width=960                 coded_width=0
coded_height=540                coded_height=0
closed_captions=0               closed_captions=0
has_b_frames=0                  has_b_frames=1
sample_aspect_ratio=1:1         sample_aspect_ratio=1:1
display_aspect_ratio=16:9       display_aspect_ratio=4:3
pix_fmt=yuv420p                 pix_fmt=yuv420p
level=1                         level=-99
color_range=unknown             color_range=tv
color_space=unknown             color_space=unknown
color_transfer=unknown          color_transfer=unknown
color_primaries=unknown         color_primaries=unknown
chroma_location=left            chroma_location=center
field_order=unknown             field_order=unknown
timecode=N/A                    timecode=N/A
refs=1                          refs=1
quarter_sample=false            
divx_packed=false               
id=N/A                          id=0x1e0
r_frame_rate=24/1               r_frame_rate=25/1
avg_frame_rate=24/1             avg_frame_rate=25/1
time_base=1/24                  time_base=1/90000
start_pts=0                     start_pts=9900
start_time=0.000000             start_time=0.110000
duration_ts=7451                duration_ts=3690000
duration=310.458333             duration=41.000000
bit_rate=4096346                bit_rate=104857200
max_bit_rate=9000000            max_bit_rate=N/A
bits_per_raw_sample=N/A         bits_per_raw_sample=N/A
nb_frames=7451                  nb_frames=N/A
nb_read_frames=N/A              nb_read_frames=N/A
nb_read_packets=N/A             nb_read_packets=N/A
DISPOSITION:default=1           DISPOSITION:default=0
DISPOSITION:dub=0               DISPOSITION:dub=0
DISPOSITION:original=0          DISPOSITION:original=0
DISPOSITION:comment=0           DISPOSITION:comment=0
DISPOSITION:lyrics=0            DISPOSITION:lyrics=0
DISPOSITION:karaoke=0           DISPOSITION:karaoke=0
DISPOSITION:forced=0            DISPOSITION:forced=0
DISPOSITION:hearing_impaired=0  DISPOSITION:hearing_impaired=0
DISPOSITION:visual_impaired=0   DISPOSITION:visual_impaired=0
DISPOSITION:clean_effects=0     DISPOSITION:clean_effects=0
DISPOSITION:attached_pic=0      DISPOSITION:attached_pic=0
DISPOSITION:timed_thumbnails=0  DISPOSITION:timed_thumbnails=0
[/STREAM]                       [/STREAM]


  


  Clearly, the MPEG-4 video is like 11 times larger than MPEG-1, but at the same time MPEG-4 video has like 100000000 less bit rate advertised than MPEG-1. And since my algorithm does not consider anything else to compute the final bit rate, that is how the problem facilitates itself. Now I tried to look into some other field values in search for a hint that maybe something else should also be included into the equation, and my suspicions lie in the following ones :

  


  time_base=1/24                  time_base=1/90000
start_pts=0                     start_pts=9900
start_time=0.000000             start_time=0.110000
duration_ts=7451                duration_ts=3690000
duration=310.458333             duration=41.000000


  


  I'm not an expert with MPEG and the documentation isn't very informative on these in a way that I could derive some math out of it or otherwise somehow connect them to resolving my issue in a meaningful way. Could anybody experienced please assist here ?

  


• ffmpeg - Can't stably save rtsp stream to file

  20 août 2022, par André Luís

  I'm trying to save the RTSP stream of this camera to file. However, at some point I'll get the following errors, which will stop the process.

  


  


  video:331639kB audio:5199kB subtitle:0kB other streams:0kB global
headers:0kB muxing overhead : unknown

  


  


  And a bunch of these, before the previous one :

  


  


  Non-monotonous DTS in output stream 0:1 ; previous : 5439375, current :
5439283 ; changing to 5439376. This may result in incorrect timestamps
in the output file.

  


  


  Here is the command I'm running :

  


  ffmpeg "rtsp://192.168.0.100:554/cam/realmonitor?channel=1&subtype=0" -c copy -f segment -segment_time 00:01:00 -reset_timestamps 1 -segment_format mkv -strftime 1 /home/user/.camera/recordings/2022/8/19/%H_%M_%S.mkv


  


  I've tried adding each of these parameters and they all together :

  


  -fflags +autobsf+genpts -y -threads 1 -use_wallclock_as_timestamps 1 -dts_delta_threshold 0 -rtsp_transport tcp -i


  


  ffprobe :

  


  {
    "streams": [
        {
            "index": 0,
            "codec_name": "h264",
            "codec_long_name": "H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10",
            "profile": "Main",
            "codec_type": "video",
            "codec_tag_string": "[0][0][0][0]",
            "codec_tag": "0x0000",
            "width": 1920,
            "height": 1080,
            "coded_width": 1920,
            "coded_height": 1080,
            "closed_captions": 0,
            "film_grain": 0,
            "has_b_frames": 0,
            "pix_fmt": "yuvj420p",
            "level": 40,
            "color_range": "pc",
            "chroma_location": "left",
            "field_order": "progressive",
            "refs": 1,
            "is_avc": "false",
            "nal_length_size": "0",
            "r_frame_rate": "100/1",
            "avg_frame_rate": "0/0",
            "time_base": "1/90000",
            "start_pts": 9000,
            "start_time": "0.100000",
            "bits_per_raw_sample": "8",
            "extradata_size": 27,
            "disposition": {
                "default": 0,
                "dub": 0,
                "original": 0,
                "comment": 0,
                "lyrics": 0,
                "karaoke": 0,
                "forced": 0,
                "hearing_impaired": 0,
                "visual_impaired": 0,
                "clean_effects": 0,
                "attached_pic": 0,
                "timed_thumbnails": 0,
                "captions": 0,
                "descriptions": 0,
                "metadata": 0,
                "dependent": 0,
                "still_image": 0
            }
        },
        {
            "index": 1,
            "codec_name": "aac",
            "codec_long_name": "AAC (Advanced Audio Coding)",
            "profile": "LC",
            "codec_type": "audio",
            "codec_tag_string": "[0][0][0][0]",
            "codec_tag": "0x0000",
            "sample_fmt": "fltp",
            "sample_rate": "16000",
            "channels": 1,
            "channel_layout": "mono",
            "bits_per_sample": 0,
            "r_frame_rate": "0/0",
            "avg_frame_rate": "0/0",
            "time_base": "1/16000",
            "start_pts": 0,
            "start_time": "0.000000",
            "extradata_size": 2,
            "disposition": {
                "default": 0,
                "dub": 0,
                "original": 0,
                "comment": 0,
                "lyrics": 0,
                "karaoke": 0,
                "forced": 0,
                "hearing_impaired": 0,
                "visual_impaired": 0,
                "clean_effects": 0,
                "attached_pic": 0,
                "timed_thumbnails": 0,
                "captions": 0,
                "descriptions": 0,
                "metadata": 0,
                "dependent": 0,
                "still_image": 0
            }
        }
    ]
}


  


  I honestly don't know what else to do.

  


• Muxer does not support non seekable output. Could not write header for output file #0

  1er janvier 2023, par artenson.art98

  I'm using ffmpeg in an Android application, and for some files I get this error :

  


  


  muxer does not support non seekable output
Could not write header for output file #0 (incorrect codec parameters ?) : Invalid argumentError initializing output stream 0:0 — [AVIOContext @ 0xb4000071b42cd7c0] Statistics : 0 bytes written, 0 seeks, 0 writeouts[aac @ 0xb4000070f28d7400] Qavg : 65536.000[aac @ 0xb4000070f28d7400] 2 frames left in the queue on closing[AVIOContext @ 0xb400007126c5e4c0] Statistics : 403202761 bytes read, 1 seeks
Conversion failed !

  


  


  The information for the input file as fetched from FFprobe is attached below along with the output logs & command. Please help me with this issue. I'm unable to try anything since I'm not sure about the cause of the issue.
Thanks in advance.

  


  Command

  


  -y -i input.mp4 -vcodec libx264 -crf 27 -filter:v scale=640:-2 -preset veryfast -c:a aac output.mp4

  


  Input file info :

  


  {
   "streams":[
      {
         "index":0,
         "codec_name":"h264",
         "codec_long_name":"unknown",
         "profile":"100",
         "codec_type":"video",
         "codec_tag_string":"avc1",
         "codec_tag":"0x31637661",
         "width":640,
         "height":360,
         "coded_width":640,
         "coded_height":360,
         "closed_captions":0,
         "film_grain":0,
         "has_b_frames":2,
         "sample_aspect_ratio":"1:1",
         "display_aspect_ratio":"16:9",
         "pix_fmt":"yuv420p",
         "level":31,
         "chroma_location":"left",
         "field_order":"progressive",
         "refs":1,
         "is_avc":"true",
         "nal_length_size":"4",
         "id":"0x1",
         "r_frame_rate":"30000\/1001",
         "avg_frame_rate":"276451589\/9224496",
         "time_base":"1\/90000",
         "start_pts":0,
         "start_time":"0.000000",
         "duration_ts":607533927,
         "duration":"6750.376967",
         "bit_rate":"372641",
         "bits_per_raw_sample":"8",
         "nb_frames":"202304",
         "extradata_size":47,
         "disposition":{
            "default":1,
            "dub":0,
            "original":0,
            "comment":0,
            "lyrics":0,
            "karaoke":0,
            "forced":0,
            "hearing_impaired":0,
            "visual_impaired":0,
            "clean_effects":0,
            "attached_pic":0,
            "timed_thumbnails":0,
            "captions":0,
            "descriptions":0,
            "metadata":0,
            "dependent":0,
            "still_image":0
         },
         "tags":{
            "language":"und",
            "handler_name":"VideoHandler",
            "vendor_id":"[0][0][0][0]"
         }
      },
      {
         "index":1,
         "codec_name":"aac",
         "codec_long_name":"unknown",
         "profile":"1",
         "codec_type":"audio",
         "codec_tag_string":"mp4a",
         "codec_tag":"0x6134706d",
         "sample_fmt":"fltp",
         "sample_rate":"48000",
         "channels":2,
         "channel_layout":"stereo",
         "bits_per_sample":0,
         "id":"0x2",
         "r_frame_rate":"0\/0",
         "avg_frame_rate":"0\/0",
         "time_base":"1\/48000",
         "start_pts":0,
         "start_time":"0.000000",
         "duration_ts":324014080,
         "duration":"6750.293333",
         "bit_rate":"96352",
         "nb_frames":"316420",
         "extradata_size":2,
         "disposition":{
            "default":1,
            "dub":0,
            "original":0,
            "comment":0,
            "lyrics":0,
            "karaoke":0,
            "forced":0,
            "hearing_impaired":0,
            "visual_impaired":0,
            "clean_effects":0,
            "attached_pic":0,
            "timed_thumbnails":0,
            "captions":0,
            "descriptions":0,
            "metadata":0,
            "dependent":0,
            "still_image":0
         },
         "tags":{
            "language":"und",
            "handler_name":"SoundHandler",
            "vendor_id":"[0][0][0][0]"
         }
      }
   ],
   "chapters":[
      
   ],
   "format":{
      "filename":"input.mp4",
      "nb_streams":2,
      "nb_programs":0,
      "format_name":"mov,mp4,m4a,3gp,3g2,mj2",
      "start_time":"0.000000",
      "duration":"6750.377000",
      "size":"403137225",
      "bit_rate":"477765",
      "probe_score":100,
      "tags":{
         "major_brand":"isom",
         "minor_version":"512",
         "compatible_brands":"isomiso2avc1mp41",
         "encoder":"Lavf59.30.101"
      }
   }
}


  


  Full output log :