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  1. Hi all, apologies for the additional thread.

    I've been building an ffmpeg code for use with my DeckLink card and with everyone's help have slowly solved all the issues. The video is now working perfectly, and the sound is nearly there too. After thinking I was out of the woods and solved all the issues, I've discovered a weird sound problem that happens in some recordings. Since it's a totally different problem I made a new thread on it. I'm recording an EAC3 source using the EAC3 codec. Occasionally however in some recordings at segments in the video the audio has a high pitched crackling and whining that is intermittent. I can work on uploading an example. A ~2 hour video file will sound excellent, and then in random segments have this issue for a few minutes at a time before sounding perfect once again. I've had this problem before but thought I had it solved when I learned I was erroneously using AC3 in ffmpeg on an EAC3 source. When I switched my command to use EAC3 the problem went away, but now it's back. I can't think of a reason for why this is in my case but there are some threads online where people discuss such a problem with ffmpeg. My ffmpeg command is below. Any ideas are appreciated. Thanks!

    Code:
    ffmpeg -f dshow -c:v v210 -video_pin_name 1 -audio_pin_name 1 -video_size 3840x2160 -rtbufsize 2147480000 -framerate 24000/1001 -channels 6 -sample_rate 48k -sample_size 16 -i video="Decklink Video Capture":audio="Decklink Audio Capture" -filter_complex "[0:0]scale=w=iw:h=ih:interl=false:eval=init:out_v_chr_pos=-128:out_h_chr_pos=-128:flags=bilinear+accurate_rnd+print_info,format=p010le[vout];[0:1]channelmap=FL-FL|FR-FR|LFE-FC|FC-LFE|BL-BL|BR-BR:5.1[aout]" -map "[vout]" -map "[aout]" -color_range 1 -chroma_sample_location left -color_trc smpte2084 -color_primaries bt2020 -colorspace bt2020nc -strict -2 -c:a eac3 -b:a 640k -c:v hevc_nvenc -profile:v main10 -preset:v p7 -b:v 70M -minrate 50M -maxrate 90M -bufsize:v 120 M title.mkv
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  2. Member
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    Originally Posted by Boxcart View Post
    Hi all, apologies for the additional thread.

    I've been building an ffmpeg code for use with my DeckLink card and with everyone's help have slowly solved all the issues. The video is now working perfectly, and the sound is nearly there too. After thinking I was out of the woods and solved all the issues, I've discovered a weird sound problem that happens in some recordings. Since it's a totally different problem I made a new thread on it. I'm recording an EAC3 source using the EAC3 codec. Occasionally however in some recordings at segments in the video the audio has a high pitched crackling and whining that is intermittent. I can work on uploading an example. A ~2 hour video file will sound excellent, and then in random segments have this issue for a few minutes at a time before sounding perfect once again. I've had this problem before but thought I had it solved when I learned I was erroneously using AC3 in ffmpeg on an EAC3 source. When I switched my command to use EAC3 the problem went away, but now it's back. I can't think of a reason for why this is in my case but there are some threads online where people discuss such a problem with ffmpeg. My ffmpeg command is below. Any ideas are appreciated. Thanks!

    Code:
    ffmpeg -f dshow -c:v v210 -video_pin_name 1 -audio_pin_name 1 -video_size 3840x2160 -rtbufsize 2147480000 -framerate 24000/1001 -channels 6 -sample_rate 48k -sample_size 16 -i video="Decklink Video Capture":audio="Decklink Audio Capture" -filter_complex "[0:0]scale=w=iw:h=ih:interl=false:eval=init:out_v_chr_pos=-128:out_h_chr_pos=-128:flags=bilinear+accurate_rnd+print_info,format=p010le[vout];[0:1]channelmap=FL-FL|FR-FR|LFE-FC|FC-LFE|BL-BL|BR-BR:5.1[aout]" -map "[vout]" -map "[aout]" -color_range 1 -chroma_sample_location left -color_trc smpte2084 -color_primaries bt2020 -colorspace bt2020nc -strict -2 -c:a eac3 -b:a 640k -c:v hevc_nvenc -profile:v main10 -preset:v p7 -b:v 70M -minrate 50M -maxrate 90M -bufsize:v 120 M title.mkv
    try using ffmpegs Normalization Filters - https://superuser.com/questions/323119/how-can-i-normalize-audio-using-ffmpeg
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  3. Originally Posted by october262 View Post
    Originally Posted by Boxcart View Post
    Hi all, apologies for the additional thread.

    I've been building an ffmpeg code for use with my DeckLink card and with everyone's help have slowly solved all the issues. The video is now working perfectly, and the sound is nearly there too. After thinking I was out of the woods and solved all the issues, I've discovered a weird sound problem that happens in some recordings. Since it's a totally different problem I made a new thread on it. I'm recording an EAC3 source using the EAC3 codec. Occasionally however in some recordings at segments in the video the audio has a high pitched crackling and whining that is intermittent. I can work on uploading an example. A ~2 hour video file will sound excellent, and then in random segments have this issue for a few minutes at a time before sounding perfect once again. I've had this problem before but thought I had it solved when I learned I was erroneously using AC3 in ffmpeg on an EAC3 source. When I switched my command to use EAC3 the problem went away, but now it's back. I can't think of a reason for why this is in my case but there are some threads online where people discuss such a problem with ffmpeg. My ffmpeg command is below. Any ideas are appreciated. Thanks!

    Code:
    ffmpeg -f dshow -c:v v210 -video_pin_name 1 -audio_pin_name 1 -video_size 3840x2160 -rtbufsize 2147480000 -framerate 24000/1001 -channels 6 -sample_rate 48k -sample_size 16 -i video="Decklink Video Capture":audio="Decklink Audio Capture" -filter_complex "[0:0]scale=w=iw:h=ih:interl=false:eval=init:out_v_chr_pos=-128:out_h_chr_pos=-128:flags=bilinear+accurate_rnd+print_info,format=p010le[vout];[0:1]channelmap=FL-FL|FR-FR|LFE-FC|FC-LFE|BL-BL|BR-BR:5.1[aout]" -map "[vout]" -map "[aout]" -color_range 1 -chroma_sample_location left -color_trc smpte2084 -color_primaries bt2020 -colorspace bt2020nc -strict -2 -c:a eac3 -b:a 640k -c:v hevc_nvenc -profile:v main10 -preset:v p7 -b:v 70M -minrate 50M -maxrate 90M -bufsize:v 120 M title.mkv
    try using ffmpegs Normalization Filters - https://superuser.com/questions/323119/how-can-i-normalize-audio-using-ffmpeg
    Before I turned to looking into the Normalization filters I randomly tried switching my command from EAC3 to AC3, since switching from AC3 to EAC3 (on an EAC3 input that I had mistakenly designated in ffmpeg as AC3) before solved the problem. Somehow miraculously the problem was solved. It does not make any sense. The input is identified as EAC3. I tried recording the same scene 10 times using the command provided above and it had the same crackling in the same scenes the same way as indicated in the example above each and every time. But then I switched the command from EAC3 to AC3 (still on an EAC3 input) and now somehow it's solved.

    I have no idea why that fixes it, and why it's so intermittent between inputs with purportedly identical formats. At this point what it seems I have to do is try the command above and if it there's the crackling problem, switch between EAC3 and AC3 and the other one will work and vice versa. Doesn't make any sense to me.
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