Skip to content

Commit

Permalink
Update ffmpeg encoding examples to directly encode with video.
Browse files Browse the repository at this point in the history 
- Provide examples to directly encode wav files and mux them with video.
- Provide a concrete example for muxing a pre-encoded 3OA+stereo IAMF file
  with video to MP4.
- No longer provide examples that encode wav files to an intermediate audio-only
  IAMF file.
- Drop the helper script that builds an ffmpeg command to merge pre-encoded IAMF
  and video files.

PiperOrigin-RevId: 715880388
  • Loading branch information
@felicialim @jwcullen
felicialim authored and jwcullen committed Jan 15, 2025
1 parent 0d69169 commit 064e5b4
Showing 1 changed file with 60 additions and 98 deletions.
158 changes: 60 additions & 98 deletions docs/external/encoding_with_external_tools.md
View file
Original file line number Diff line number Diff line change
Expand Up @@ -5,11 +5,7 @@ wav files to IAMF and merge with a video file into an MP4 file. Some example
commands are listed below. See the [official ffmpeg
documentation](https://www.ffmpeg.org/ffmpeg.html) for more details.

## Encode wav files to IAMF with ffmpeg

The [FFmpeg](https://www.ffmpeg.org/) CLI can be used to encode a set of
input wav files into a standalone IAMF Sequence (`.iamf`) file or IAMF
encapsulated in MP4.
## Encode IAMF audio and merge with video using ffmpeg

The examples below encode input wav files to IAMF using Opus to encode the
underlying audio elements at 64 kbps per channel.
Expand Down Expand Up @@ -48,87 +44,92 @@ Usage notes:

### Encoding stereo wav to IAMF

Replace `/path/to/input.wav` and `/path/to/output_iamf_or_mp4`.
Replace `/path/to/input.wav`, `/path/to/video.mp4` and `/path/to/output.mp4`.

```shell
ffmpeg -i /path/to/input.wav \
-i /path/to/video.mp4 -c:v copy \
-filter_complex "[0:a]channelmap=0|1:stereo[FRONT]" \
-map "[FRONT]" \
-map "[FRONT]" -map 1:0 \
-stream_group "type=iamf_audio_element:id=1:st=0:audio_element_type=channel,layer=ch_layout=stereo" \
-stream_group "type=iamf_mix_presentation:id=3:stg=0:annotations=en-us=default_mix_presentation,submix=parameter_id=100:parameter_rate=48000:default_mix_gain=0.0|element=stg=0:headphones_rendering_mode=binaural:annotations=en-us=stereo:parameter_id=101:parameter_rate=48000:default_mix_gain=0.0|layout=sound_system=stereo:integrated_loudness=0.0:digital_peak=0.0" \
-streamid 0:0 \
-c:a libopus -b:a 64000 /path/to/output_iamf_or_mp4
-streamid 0:0 -streamid 1:1 \
-c:a libopus -b:a 64000 /path/to/output.mp4
```

### Encoding 5.1 wav to IAMF

Replace `/path/to/input.wav` and `/path/to/output_iamf_or_mp4`.
Replace `/path/to/input.wav`, `/path/to/video.mp4` and `/path/to/output.mp4`.

```shell
ffmpeg -i /path/to/input.wav \
-i /path/to/video.mp4 -c:v copy \
-filter_complex "[0:a]channelmap=0|1:stereo[FRONT];[0:a]channelmap=4|5:stereo[BACK];[0:a]channelmap=2:mono[CENTER];[0:a]channelmap=3:mono[LFE]" \
-map "[FRONT]" -map "[BACK]" -map "[CENTER]" -map "[LFE]" \
-map "[FRONT]" -map "[BACK]" -map "[CENTER]" -map "[LFE]" -map 1:0 \
-stream_group "type=iamf_audio_element:id=1:st=0:st=1:st=2:st=3:audio_element_type=channel,layer=ch_layout=5.1" \
-stream_group "type=iamf_mix_presentation:id=3:stg=0:annotations=en-us=default_mix_presentation,submix=parameter_id=100:parameter_rate=48000:default_mix_gain=0.0|element=stg=0:headphones_rendering_mode=binaural:annotations=en-us=5.1:parameter_id=101:parameter_rate=48000:default_mix_gain=0.0|layout=sound_system=stereo:integrated_loudness=0.0:digital_peak=0.0" \
-streamid 0:0 -streamid 1:1 -streamid 2:2 -streamid 3:3 \
-c:a libopus -b:a 64000 /path/to/output_iamf_or_mp4
-streamid 0:0 -streamid 1:1 -streamid 2:2 -streamid 3:3 -streamid 4:4 \
-c:a libopus -b:a 64000 /path/to/output.mp4
```

### Encoding 5.1.2 wav to IAMF

Replace `/path/to/input.wav` and `/path/to/output_iamf_or_mp4`.
Replace `/path/to/input.wav`, `/path/to/video.mp4` and `/path/to/output.mp4`.

```shell
ffmpeg -i /path/to/input.wav \
-i /path/to/video.mp4 -c:v copy \
-filter_complex "[0:a]channelmap=0|1:stereo[FRONT];[0:a]channelmap=4|5:stereo[BACK];[0:a]channelmap=6|7:stereo[TOP_FRONT];[0:a]channelmap=2:mono[CENTER];[0:a]channelmap=3:mono[LFE]" \
-map "[FRONT]" -map "[BACK]" -map "[TOP_FRONT]" -map "[CENTER]" -map "[LFE]"
\
-map "[FRONT]" -map "[BACK]" -map "[TOP_FRONT]" -map "[CENTER]" -map "[LFE]" -map 1:0 \
-stream_group "type=iamf_audio_element:id=1:st=0:st=1:st=2:st=3:st=4:audio_element_type=channel,layer=ch_layout=5.1.2" \
-stream_group "type=iamf_mix_presentation:id=3:stg=0:annotations=en-us=default_mix_presentation,submix=parameter_id=100:parameter_rate=48000:default_mix_gain=0.0|element=stg=0:headphones_rendering_mode=binaural:annotations=en-us=5.1.2:parameter_id=101:parameter_rate=48000:default_mix_gain=0.0|layout=sound_system=stereo:integrated_loudness=0.0:digital_peak:0.0" \
-streamid 0:0 -streamid 1:1 -streamid 2:2 -streamid 3:3 -streamid 4:4 \
-c:a libopus -b:a 64000 /path/to/output_iamf_or_mp4
-stream_group "type=iamf_mix_presentation:id=3:stg=0:annotations=en-us=default_mix_presentation,submix=parameter_id=100:parameter_rate=48000:default_mix_gain=0.0|element=stg=0:headphones_rendering_mode=binaural:annotations=en-us=5.1.2:parameter_id=101:parameter_rate=48000:default_mix_gain=0.0|layout=sound_system=stereo:integrated_loudness=0.0:digital_peak=0.0" \
-streamid 0:0 -streamid 1:1 -streamid 2:2 -streamid 3:3 -streamid 4:4 -streamid 5:5 \
-c:a libopus -b:a 64000 /path/to/output.mp4
```

### Encoding 7.1.4 wav to IAMF

Replace `/path/to/input.wav` and `/path/to/output_iamf_or_mp4`.
Replace `/path/to/input.wav`, `/path/to/video.mp4` and `/path/to/output.mp4`.

```shell
ffmpeg -i /path/to/input.wav \
ffmpeg -i /path/to/input.wav -i \
/path/to/video.mp4 -c:v copy \
-filter_complex "[0:a]channelmap=0|1:stereo[FRONT];[0:a]channelmap=4|5:stereo[SIDE];[0:a]channelmap=6|7:stereo[BACK];[0:a]channelmap=8|9:stereo[TOP_FRONT];[0:a]channelmap=10|11:stereo[TOP_BACK];[0:a]channelmap=2:mono[CENTER];[0:a]channelmap=3:mono[LFE]" \
-map "[FRONT]" -map "[SIDE]" -map "[BACK]" -map "[TOP_FRONT]" -map "[TOP_BACK]" -map "[CENTER]" -map "[LFE]" \
-map "[FRONT]" -map "[SIDE]" -map "[BACK]" -map "[TOP_FRONT]" -map "[TOP_BACK]" -map "[CENTER]" -map "[LFE]" -map 1:0 \
-stream_group "type=iamf_audio_element:id=1:st=0:st=1:st=2:st=3:st=4:st=5:st=6:audio_element_type=channel,layer=ch_layout=7.1.4" \
-stream_group "type=iamf_mix_presentation:id=3:stg=0:annotations=en-us=default_mix_presentation,submix=parameter_id=100:parameter_rate=48000:default_mix_gain=0.0|element=stg=0:headphones_rendering_mode=binaural:annotations=en-us=7.1.4:parameter_id=101:parameter_rate=48000:default_mix_gain=0.0|layout=sound_system=stereo:integrated_loudness=0.0:digital_peak=0.0" \
-streamid 0:0 -streamid 1:1 -streamid 2:2 -streamid 3:3 -streamid 4:4 -streamid 5:5 -streamid 6:6 \
-c:a libopus -b:a 64000 /path/to/output_iamf_or_mp4
-streamid 0:0 -streamid 1:1 -streamid 2:2 -streamid 3:3 -streamid 4:4 -streamid 5:5 -streamid 6:6 -streamid 7:7 \
-c:a libopus -b:a 64000 /path/to/output.mp4
```

### Encoding 1st order Ambisonics wav to IAMF

Replace `/path/to/input.wav` and `/path/to/output_iamf_or_mp4`.
Replace `/path/to/input.wav`, `/path/to/video.mp4` and `/path/to/output.mp4`.

```shell
ffmpeg -i /path/to/input.wav \
-i /path/to/video.mp4 -c:v copy \
-filter_complex "[0:a]channelmap=0:mono[A0];[0:a]channelmap=1:mono[A1];[0:a]channelmap=2:mono[A2];[0:a]channelmap=3:mono[A3]" \
-map "[A0]" -map "[A1]" -map "[A2]" -map "[A3]" \
-map "[A0]" -map "[A1]" -map "[A2]" -map "[A3]" -map 1:0 \
-stream_group "type=iamf_audio_element:id=1:st=0:st=1:st=2:st=3:audio_element_type=scene,layer=ch_layout=ambisonic\ 1:ambisonics_mode=mono," \
-stream_group "type=iamf_mix_presentation:id=3:stg=0:annotations=en-us=default_mix_presentation,submix=parameter_id=100:parameter_rate=48000:default_mix_gain=0.0|element=stg=0:headphones_rendering_mode=binaural:annotations=en-us=FOA:parameter_id=101:parameter_rate=48000:default_mix_gain=0.0|layout=sound_system=stereo:integrated_loudness=0.0:digital_peak=0.0" \
-streamid 0:0 -streamid 1:1 -streamid 2:2 -streamid 3:3 \
-c:a libopus -b:a 64000 /path/to/output_iamf_or_mp4
-streamid 0:0 -streamid 1:1 -streamid 2:2 -streamid 3:3 -streamid 4:4 \
-c:a libopus -b:a 64000 /path/to/output.mp4
```

### Encoding 3rd order Ambisonics wav to IAMF

Replace `/path/to/input.wav` and `/path/to/output_iamf_or_mp4`.
Replace `/path/to/input.wav`, `/path/to/video.mp4` and `/path/to/output.mp4`.

```shell
ffmpeg -i /path/to/input.wav \
-i /path/to/video.mp4 -c:v copy \
-filter_complex "[0:a]channelmap=0:mono[A0];[0:a]channelmap=1:mono[A1];[0:a]channelmap=2:mono[A2];[0:a]channelmap=3:mono[A3];[0:a]channelmap=4:mono[A4];[0:a]channelmap=5:mono[A5];[0:a]channelmap=6:mono[A6];[0:a]channelmap=7:mono[A7];[0:a]channelmap=8:mono[A8];[0:a]channelmap=9:mono[A9];[0:a]channelmap=10:mono[A10];[0:a]channelmap=11:mono[A11];[0:a]channelmap=12:mono[A12];[0:a]channelmap=13:mono[A13];[0:a]channelmap=14:mono[A14];[0:a]channelmap=15:mono[A15]" \
-map "[A0]" -map "[A1]" -map "[A2]" -map "[A3]" -map "[A4]" -map "[A5]" -map "[A6]" -map "[A7]" -map "[A8]" -map "[A9]" -map "[A10]" -map "[A11]" -map "[A12]" -map "[A13]" -map "[A14]" -map "[A15]" \
-map "[A0]" -map "[A1]" -map "[A2]" -map "[A3]" -map "[A4]" -map "[A5]" -map "[A6]" -map "[A7]" -map "[A8]" -map "[A9]" -map "[A10]" -map "[A11]" -map "[A12]" -map "[A13]" -map "[A14]" -map "[A15]" -map 1:0 \
-stream_group "type=iamf_audio_element:id=1:st=0:st=1:st=2:st=3:st=4:st=5:st=6:st=7:st=8:st=9:st=10:st=11:st=12:st=13:st=14:st=15:audio_element_type=scene,layer=ch_layout=ambisonic\ 3:ambisonics_mode=mono," \
-stream_group "type=iamf_mix_presentation:id=3:stg=0:annotations=en-us=default_mix_presentation,submix=parameter_id=100:parameter_rate=48000:default_mix_gain=0.0|element=stg=0:headphones_rendering_mode=binaural:annotations=en-us=3OA:parameter_id=101:parameter_rate=48000:default_mix_gain=0.0|layout=sound_system=stereo:integrated_loudness=0.0:digital_peak=0.0" \
-streamid 0:0 -streamid 1:1 -streamid 2:2 -streamid 3:3 -streamid 4:4 -streamid 5:5 -streamid 6:6 -streamid 7:7 -streamid 8:8 -streamid 9:9 -streamid 10:10 -streamid 11:11 -streamid 12:12 -streamid 13:13 -streamid 14:14 -streamid 15:15 \
-c:a libopus -b:a 64000 /path/to/output_iamf_or_mp4
-streamid 0:0 -streamid 1:1 -streamid 2:2 -streamid 3:3 -streamid 4:4 -streamid 5:5 -streamid 6:6 -streamid 7:7 -streamid 8:8 -streamid 9:9 -streamid 10:10 -streamid 11:11 -streamid 12:12 -streamid 13:13 -streamid 14:14 -streamid 15:15 -streamid 16:16 \
-c:a libopus -b:a 64000 /path/to/output.mp4
```

### Encoding 1st order Ambisonics and stereo wavs to IAMF
Expand All @@ -137,7 +138,8 @@ This example takes 2 input wav files. Replace the following:

- `/path/to/input_FOA.wav`
- `/path/to/input_stereo.wav`
- `/path/to/output_iamf_or_mp4`
- `/path/to/video.mp4`
- `/path/to/output.mp4`

By default, the `headphones_rendering_mode` is set to `binaural` for the
ambisonics input, and `stereo` for the stereo input, with the assumption that
Expand All @@ -147,15 +149,15 @@ binauralized instead of downmixed to stereo, change both instances of

```shell
ffmpeg -i /path/to/input_FOA.wav -i /path/to/input_stereo.wav \
-i /path/to/video.mp4 -c:v copy \
-filter_complex "[0:a]channelmap=0:mono[A0];[0:a]channelmap=1:mono[A1];[0:a]channelmap=2:mono[A2];[0:a]channelmap=3:mono[A3]" \
-map "[A0]" -map "[A1]" -map "[A2]" -map "[A3]" \
-stream_group "type=iamf_audio_element:id=1:st=0:st=1:st=2:st=3:audio_element_type=scene,layer=ch_layout=ambisonic\ 1:ambisonics_mode=mono," \
-filter_complex "[1:a]channelmap=0|1:stereo[FRONT]" \
-map "[FRONT]" \
-map "[A0]" -map "[A1]" -map "[A2]" -map "[A3]" -map "[FRONT]" -map 2:0 \
-stream_group "type=iamf_audio_element:id=1:st=0:st=1:st=2:st=3:audio_element_type=scene,layer=ch_layout=ambisonic\ 1:ambisonics_mode=mono," \
-stream_group "type=iamf_audio_element:id=2:st=4:audio_element_type=channel,layer=ch_layout=stereo" \
-stream_group "type=iamf_mix_presentation:id=3:stg=0:stg=1:annotations=en-us=default_mix_presentation,submix=parameter_id=100:parameter_rate=48000:default_mix_gain=0.0|element=stg=0:headphones_rendering_mode=binaural:annotations=en-us=FOA:parameter_id=101:parameter_rate=48000:default_mix_gain=0.0|element=stg=1:headphones_rendering_mode=stereo:annotations=en-us=stereo:parameter_id=101:parameter_rate=48000:default_mix_gain=0.0|layout=sound_system=stereo:integrated_loudness=0.0:digital_peak=0.0" \
-streamid 0:0 -streamid 1:1 -streamid 2:2 -streamid 3:3 -streamid 4:4 \
-c:a libopus -b:a 64000 /path/to/output_iamf_or_mp4
-streamid 0:0 -streamid 1:1 -streamid 2:2 -streamid 3:3 -streamid 4:4 -streamid 5:5 \
-c:a libopus -b:a 64000 /path/to/output.mp4
```

### Encoding 3rd order Ambisonics and stereo wavs to IAMF
Expand All @@ -164,7 +166,8 @@ This example takes 2 input wav files. Replace the following:

- `/path/to/input_TOA.wav`
- `/path/to/input_stereo.wav`
- `/path/to/output_iamf_or_mp4`
- `/path/to/video.mp4`
- `/path/to/output.mp4`

By default, the `headphones_rendering_mode` is set to `binaural` for the
ambisonics input, and `stereo` for the stereo input, with the assumption that
Expand All @@ -174,75 +177,34 @@ binauralized instead of downmixed to stereo, change both instances of

```shell
ffmpeg -i /path/to/input_TOA.wav -i /path/to/input_stereo.wav \
-i /path/to/video.mp4 -c:v copy \
-filter_complex "[0:a]channelmap=0:mono[A0];[0:a]channelmap=1:mono[A1];[0:a]channelmap=2:mono[A2];[0:a]channelmap=3:mono[A3];[0:a]channelmap=4:mono[A4];[0:a]channelmap=5:mono[A5];[0:a]channelmap=6:mono[A6];[0:a]channelmap=7:mono[A7];[0:a]channelmap=8:mono[A8];[0:a]channelmap=9:mono[A9];[0:a]channelmap=10:mono[A10];[0:a]channelmap=11:mono[A11];[0:a]channelmap=12:mono[A12];[0:a]channelmap=13:mono[A13];[0:a]channelmap=14:mono[A14];[0:a]channelmap=15:mono[A15]" \
-map "[A0]" -map "[A1]" -map "[A2]" -map "[A3]" -map "[A4]" -map "[A5]" -map "[A6]" -map "[A7]" -map "[A8]" -map "[A9]" -map "[A10]" -map "[A11]" -map "[A12]" -map "[A13]" -map "[A14]" -map "[A15]" \
-stream_group "type=iamf_audio_element:id=1:st=0:st=1:st=2:st=3:st=4:st=5:st=6:st=7:st=8:st=9:st=10:st=11:st=12:st=13:st=14:st=15:audio_element_type=scene,layer=ch_layout=ambisonic\ 3:ambisonics_mode=mono," \
-filter_complex "[1:a]channelmap=0|1:stereo[FRONT]" \
-map "[FRONT]" \
-map "[A0]" -map "[A1]" -map "[A2]" -map "[A3]" -map "[A4]" -map "[A5]" -map "[A6]" -map "[A7]" -map "[A8]" -map "[A9]" -map "[A10]" -map "[A11]" -map "[A12]" -map "[A13]" -map "[A14]" -map "[A15]" -map "[FRONT]" -map 2:0 \
-stream_group "type=iamf_audio_element:id=1:st=0:st=1:st=2:st=3:st=4:st=5:st=6:st=7:st=8:st=9:st=10:st=11:st=12:st=13:st=14:st=15:audio_element_type=scene,layer=ch_layout=ambisonic\ 3:ambisonics_mode=mono," \
-stream_group "type=iamf_audio_element:id=2:st=16:audio_element_type=channel,layer=ch_layout=stereo" \
-stream_group "type=iamf_mix_presentation:id=3:stg=0:stg=1:annotations=en-us=default_mix_presentation,submix=parameter_id=100:parameter_rate=48000:default_mix_gain=0.0|element=stg=0:headphones_rendering_mode=binaural:annotations=en-us=3OA:parameter_id=101:parameter_rate=48000:default_mix_gain=0.0|element=stg=1:headphones_rendering_mode=stereo:annotations=en-us=stereo:parameter_id=101:parameter_rate=48000:default_mix_gain=0.0|layout=sound_system=stereo:integrated_loudness=0.0:digital_peak=0.0" \
-streamid 0:0 -streamid 1:1 -streamid 2:2 -streamid 3:3 -streamid 4:4 -streamid 5:5 -streamid 6:6 -streamid 7:7 -streamid 8:8 -streamid 9:9 -streamid 10:10 -streamid 11:11 -streamid 12:12 -streamid 13:13 -streamid 14:14 -streamid 15:15 -streamid 16:16 \
-c:a libopus -b:a 64000 /path/to/output_iamf_or_mp4
-streamid 0:0 -streamid 1:1 -streamid 2:2 -streamid 3:3 -streamid 4:4 -streamid 5:5 -streamid 6:6 -streamid 7:7 -streamid 8:8 -streamid 9:9 -streamid 10:10 -streamid 11:11 -streamid 12:12 -streamid 13:13 -streamid 14:14 -streamid 15:15 -streamid 16:16 -streamid 17:17 \
-c:a libopus -b:a 64000 /path/to/output.mp4
```

## Merge an IAMF file with video into MP4 using ffmpeg

The [FFmpeg](https://www.ffmpeg.org/) CLI can be used to merge a standalone IAMF
sequence (`.iamf`) file with an existing video into an MP4 file.
The [FFmpeg](https://www.ffmpeg.org/) CLI can be used to merge an IAMF file with
another video file into an MP4 file.

To create the MP4 file, ffmpeg requires that the `stream_groups` and `streamid`s
from an input IAMF file are copied. The helper script below is an example of
how ffprobe could be used to detect the stream groups and stream ids in the
input IAMF file, and provided to ffmpeg to merge the video and IAMF file into an
output MP4 file.
from an input IAMF file are copied. The example below merges an IAMF file
containing 3rd order Ambisonics and stereo with a video file.

```shell
#!/bin/bash

# Replace the following paths
input_iamf="/path/to/input.iamf" # This may also be an MP4 with IAMF audio.
input_video="/path/to/input_video.mp4"
output_mp4="/path/to/output.mp4"

# ffmpeg needs to copy stream groups and stream ids when creating IAMF files.
# Use ffprobe to detect the stream groups and streams in the input IAMF file.
stream_groups_count=$(ffprobe \
-v error \
-select_streams a \
-show_entries stream=index \
-of json \
$input_iamf | \
jq '.stream_groups | length')

# Assumes there is at least one stream group, and that all stream groups have
# the same number of streams.
stream_count=$(ffprobe \
-v error \
-select_streams a \
-show_entries stream=index \
-of json \
$input_iamf | \
jq '.stream_groups[0]' | jq '.streams | length')

# Construct the partial commands to copy stream groups and stream IDs.
st_map=""
for (( i=0; i<$stream_count; i++ )); do
st_map="$st_map:st=$i"
done

streamid_map=""
for (( i=0; i<$stream_count; i++ )); do
streamid_map="$streamid_map -streamid $i:$i"
done

# Merge with the video file to create the final MP4 file.
ffmpeg \
-i $input_iamf \
-i $input_video \
-c:a copy -map 0:a \
-c:v copy -map 1:v:0 \
-stream_group map=0=0$st_map \
-stream_group map=0=1$st_map \
$streamid_map \
$output_mp4
ffmpeg -i /path/to/3OA_and_stereo_iamf.mp4 \
/path/to/video.mp4 \
-c:v copy -c:a copy \
-map 0:a:0 -map 0:a:1 -map 0:a:2 -map 0:a:3 -map 0:a:4 -map 0:a:5 -map 0:a:6 -map 0:a:7 -map 0:a:8 -map 0:a:9 -map 0:a:10 -map 0:a:11 -map 0:a:12 -map 0:a:13 -map 0:a:14 -map 0:a:15 -map 0:a:16 -map 1:v:0 \
-stream_group map=0=0:st=0:st=1:st=2:st=3:st=4:st=5:st=6:st=7:st=8:st=9:st=10:st=11:st=12:st=13:st=14:st=15 \
-stream_group map=0=1:st=16 \
-stream_group map=0=2 \
-streamid 0:0 -streamid 1:1 -streamid 2:2 -streamid 3:3 -streamid 4:4 -streamid 5:5 -streamid 6:6 -streamid 7:7 -streamid 8:8 -streamid 9:9 -streamid 10:10 -streamid 11:11 -streamid 12:12 -streamid 13:13 -streamid 14:14 -streamid 15:15 -streamid 16:16 \
/path/to/output.mp4
```

0 comments on commit 064e5b4

Please sign in to comment.