Video clip loads in with no visuals (blank white)

[tjmurphy]

What is your operating system?
Ubuntu 20.04
What is your Shotcut version (see Help > About Shotcut)? Is it 32-bit?
20.09.13. No evidence of being 32 bit.

Can you repeat the problem? If so, what are the steps?
Steps to reproduce:
youtube-dl https://www.youtube.com/watch?v=370zqr5Z_4E
This produces a file titled “the world is gonna roll me-370zqr5Z_4E.mp4”
To ensure we’re looking at the same file:
md5sum ./the\ world\ is\ gonna\ roll\ me-370zqr5Z_4E.mp4 gives ea7b6c55afa281ee510426035b762fef
Now, go into a Shotcut project. In upper left, Open File. Select the file. “Good morning Hank, it’s Tuesday” can be heard, but the preview panel shows blank white (the same as what I see if I Open File to an MP3 or WAV file).
And to validate the file itself,
vlc ./the\ world\ is\ gonna\ roll\ me-370zqr5Z_4E.mp4 plays the video perfectly, visuals, audio, and everything else.

I have tried uninstalling and reinstalling Shotcut and I get the same behavior. Using youtube-dl on other videos produces a file that Shotcut can open perfectly. It is only this one video that goes to the blank white screen.

[brian]

Can you post a screenshot of the properties panel in Shotcut for the file?

[tjmurphy]

Certainly! I believe this is the panel you’re looking for? Apologies if it’s wrong; I’m happy to follow up with any other diagnostic info you’d like.

[brian]

Yes. Would be good to see what is shown in the video tab since your problem is with video.

[tjmurphy]

I can’t select the video tab, only Audio and Metadata. I click Video and nothing happens.

[brian]

That means Shotcut does not think there is a video stream. As a next step… in the properties panel hamburger menu there is an option for “More Information…” which will give the output of ffprobe. Paste that output here so we can have a look.

[tjmurphy]

Great, here you go. Interesting that it does pull out a video width and height:

ffprobe output

[streams.stream.0]

index=0

codec_name=av1

codec_long_name=Alliance for Open Media AV1

profile=unknown

codec_type=video

codec_tag_string=av01

codec_tag=0x31307661

width=3840

height=2160

has_b_frames=0

sample_aspect_ratio=N/A

display_aspect_ratio=N/A

pix_fmt=unknown

level=-99

color_range=unknown

color_space=unknown

color_transfer=unknown

color_primaries=unknown

chroma_location=unspecified

field_order=unknown

timecode=N/A

id=N/A

r_frame_rate=24000/1001

avg_frame_rate=5316000/221683

time_base=1/24000

start_pts=0

start_time=0:00:00.000000

duration_ts=5763758

duration=0:04:00.156583

bit_rate=14.066026 Mbit/s

max_bit_rate=N/A

bits_per_raw_sample=N/A

nb_frames=5759

nb_read_frames=N/A

nb_read_packets=N/A

[streams.stream.0.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

[streams.stream.0.tags]

language=und

handler_name=ISO Media file produced by Google Inc.

[streams.stream.1]

index=1

codec_name=aac

codec_long_name=AAC (Advanced Audio Coding)

profile=LC

codec_type=audio

codec_time_base=1/44100

codec_tag_string=mp4a

codec_tag=0x6134706d

sample_fmt=fltp

sample_rate=44.100000 KHz

channels=2

channel_layout=stereo

bits_per_sample=0

id=N/A

r_frame_rate=0/0

avg_frame_rate=0/0

time_base=1/44100

start_pts=0

start_time=0:00:00.000000

duration_ts=10595328

duration=0:04:00.256871

bit_rate=128 Kbit/s

max_bit_rate=128 Kbit/s

bits_per_raw_sample=N/A

nb_frames=10347

nb_read_frames=N/A

nb_read_packets=N/A

[streams.stream.1.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

[streams.stream.1.tags]

language=eng

handler_name=ISO Media file produced by Google Inc.

[format]

filename=[redacted]/the world is gonna roll me-370zqr5Z_4E.mp4

nb_streams=2

nb_programs=0

format_name=mov,mp4,m4a,3gp,3g2,mj2

format_long_name=QuickTime / MOV

start_time=0:00:00.000000

duration=0:04:00.257000

size=406.494642 Mibyte

bit_rate=14.192819 Mbit/s

probe_score=100

[format.tags]

major_brand=isom

minor_version=512

compatible_brands=isomiso2mp41

encoder=Lavf58.29.100

Completed successfully in 00:00:00

[brian]

That output is very helpful.

The clip is encoded with AV1. Shotcut uses FFMpeg for video decoding. FFMpeg does not have built-in support for AV1 decoding. FFMpeg can decode AV1 when compiled with libdav1d. We do not build libdav1d into the FFMpeg provided with Shotcut.

I have filed an issues here as a reminded for us to visit this for the next release:

Add libdav1d to FFMpeg build to support AV1 files

In the meantime, I think your best option would be to find some way to transcode the file to H.264/AVC, H.265/HEVC, or some other intermediate format.

[Austin]

Is there interest in adding libsvtav1 as well for encoding? It was incorporated into FFmpeg as of 4.3.1 and has huge optimizations for AVX2 and AVX512 processors. I was tempted to make a pull request to add it myself. AV1 has finally arrived as a usable format with libsvtav1.

[brian]

@Austin

Is there interest in adding libsvtav1 as well for encoding?

Yes. I believe so.

It should be as easy as modifying the build script:

mltframework/shotcut/blob/master/scripts/build-shotcut.sh

Keep in mind that we need the script to work for three architectures. But usually, if someone can get one architecture to work, it isn’t to hard to make the others work.