1 files changed, 313 insertions, 0 deletions
diff --git a/internal/media/ffmpeg.go b/internal/media/ffmpeg.go
new file mode 100644
index 000000000..eb94849f0
--- /dev/null
+++ b/internal/media/ffmpeg.go
@@ -0,0 +1,313 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package media
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"os"
+	"path"
+	"strconv"
+	"strings"
+
+	"codeberg.org/gruf/go-byteutil"
+
+	"codeberg.org/gruf/go-ffmpreg/wasm"
+	_ffmpeg "github.com/superseriousbusiness/gotosocial/internal/media/ffmpeg"
+
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/tetratelabs/wazero"
+)
+
+// ffmpegClearMetadata generates a copy (in-place) of input media with all metadata cleared.
+func ffmpegClearMetadata(ctx context.Context, filepath string, ext string) error {
+	// Get directory from filepath.
+	dirpath := path.Dir(filepath)
+
+	// Generate output file path with ext.
+	outpath := filepath + "_cleaned." + ext
+
+	// Clear metadata with ffmpeg.
+	if err := ffmpeg(ctx, dirpath,
+		"-loglevel", "error",
+		"-i", filepath,
+		"-map_metadata", "-1",
+		"-codec", "copy",
+		"-y",
+		outpath,
+	); err != nil {
+		return err
+	}
+
+	// Move the new output file path to original location.
+	if err := os.Rename(outpath, filepath); err != nil {
+		return gtserror.Newf("error renaming %s: %w", outpath, err)
+	}
+
+	return nil
+}
+
+// ffmpegGenerateThumb generates a thumbnail jpeg from input media of any type, useful for any media.
+func ffmpegGenerateThumb(ctx context.Context, filepath string, width, height int) (string, error) {
+	// Get directory from filepath.
+	dirpath := path.Dir(filepath)
+
+	// Generate output frame file path.
+	outpath := filepath + "_thumb.jpg"
+
+	// Generate thumb with ffmpeg.
+	if err := ffmpeg(ctx, dirpath,
+		"-loglevel", "error",
+		"-i", filepath,
+		"-filter:v", "thumbnail=n=10",
+		"-filter:v", "scale="+strconv.Itoa(width)+":"+strconv.Itoa(height),
+		"-qscale:v", "12", // ~ 70% quality
+		"-frames:v", "1",
+		"-y",
+		outpath,
+	); err != nil {
+		return "", err
+	}
+
+	return outpath, nil
+}
+
+// ffmpegGenerateStatic generates a static png from input image of any type, useful for emoji.
+func ffmpegGenerateStatic(ctx context.Context, filepath string) (string, error) {
+	// Get directory from filepath.
+	dirpath := path.Dir(filepath)
+
+	// Generate output static file path.
+	outpath := filepath + "_static.png"
+
+	// Generate static with ffmpeg.
+	if err := ffmpeg(ctx, dirpath,
+		"-loglevel", "error",
+		"-i", filepath,
+		"-codec:v", "png", // specifically NOT 'apng'
+		"-frames:v", "1", // in case animated, only take 1 frame
+		"-y",
+		outpath,
+	); err != nil {
+		return "", err
+	}
+
+	return outpath, nil
+}
+
+// ffmpeg calls `ffmpeg [args...]` (WASM) with directory path mounted in runtime.
+func ffmpeg(ctx context.Context, dirpath string, args ...string) error {
+	var stderr byteutil.Buffer
+	rc, err := _ffmpeg.Ffmpeg(ctx, wasm.Args{
+		Stderr: &stderr,
+		Args:   args,
+		Config: func(modcfg wazero.ModuleConfig) wazero.ModuleConfig {
+			fscfg := wazero.NewFSConfig()
+			fscfg = fscfg.WithDirMount(dirpath, dirpath)
+			modcfg = modcfg.WithFSConfig(fscfg)
+			return modcfg
+		},
+	})
+	if err != nil {
+		return gtserror.Newf("error running: %w", err)
+	} else if rc != 0 {
+		return gtserror.Newf("non-zero return code %d (%s)", rc, stderr.B)
+	}
+	return nil
+}
+
+// ffprobe calls `ffprobe` (WASM) on filepath, returning parsed JSON output.
+func ffprobe(ctx context.Context, filepath string) (*ffprobeResult, error) {
+	var stdout byteutil.Buffer
+
+	// Get directory from filepath.
+	dirpath := path.Dir(filepath)
+
+	// Run ffprobe on our given file at path.
+	_, err := _ffmpeg.Ffprobe(ctx, wasm.Args{
+		Stdout: &stdout,
+
+		Args: []string{
+			"-i", filepath,
+			"-loglevel", "quiet",
+			"-print_format", "json",
+			"-show_streams",
+			"-show_format",
+			"-show_error",
+		},
+
+		Config: func(modcfg wazero.ModuleConfig) wazero.ModuleConfig {
+			fscfg := wazero.NewFSConfig()
+			fscfg = fscfg.WithReadOnlyDirMount(dirpath, dirpath)
+			modcfg = modcfg.WithFSConfig(fscfg)
+			return modcfg
+		},
+	})
+	if err != nil {
+		return nil, gtserror.Newf("error running: %w", err)
+	}
+
+	var result ffprobeResult
+
+	// Unmarshal the ffprobe output as our result type.
+	if err := json.Unmarshal(stdout.B, &result); err != nil {
+		return nil, gtserror.Newf("error unmarshaling json: %w", err)
+	}
+
+	return &result, nil
+}
+
+// ffprobeResult contains parsed JSON data from
+// result of calling `ffprobe` on a media file.
+type ffprobeResult struct {
+	Streams []ffprobeStream `json:"streams"`
+	Format  *ffprobeFormat  `json:"format"`
+	Error   *ffprobeError   `json:"error"`
+}
+
+// ImageMeta extracts image metadata contained within ffprobe'd media result streams.
+func (res *ffprobeResult) ImageMeta() (width int, height int, err error) {
+	for _, stream := range res.Streams {
+		if stream.Width > width {
+			width = stream.Width
+		}
+		if stream.Height > height {
+			height = stream.Height
+		}
+	}
+	if width == 0 || height == 0 {
+		err = errors.New("invalid image stream(s)")
+	}
+	return
+}
+
+// VideoMeta extracts video metadata contained within ffprobe'd media result streams.
+func (res *ffprobeResult) VideoMeta() (width, height int, framerate float32, err error) {
+	for _, stream := range res.Streams {
+		if stream.Width > width {
+			width = stream.Width
+		}
+		if stream.Height > height {
+			height = stream.Height
+		}
+		if fr := stream.GetFrameRate(); fr > 0 {
+			if framerate == 0 || fr < framerate {
+				framerate = fr
+			}
+		}
+	}
+	if width == 0 || height == 0 || framerate == 0 {
+		err = errors.New("invalid video stream(s)")
+	}
+	return
+}
+
+type ffprobeStream struct {
+	CodecName    string `json:"codec_name"`
+	AvgFrameRate string `json:"avg_frame_rate"`
+	Width        int    `json:"width"`
+	Height       int    `json:"height"`
+	// + unused fields.
+}
+
+// GetFrameRate calculates float32 framerate value from stream json string.
+func (str *ffprobeStream) GetFrameRate() float32 {
+	if str.AvgFrameRate != "" {
+		var (
+			// numerator
+			num float32
+
+			// denominator
+			den float32
+		)
+
+		// Check for a provided inequality, i.e. numerator / denominator.
+		if p := strings.SplitN(str.AvgFrameRate, "/", 2); len(p) == 2 {
+			n, _ := strconv.ParseFloat(p[0], 32)
+			d, _ := strconv.ParseFloat(p[1], 32)
+			num, den = float32(n), float32(d)
+		} else {
+			n, _ := strconv.ParseFloat(p[0], 32)
+			num = float32(n)
+		}
+
+		return num / den
+	}
+	return 0
+}
+
+type ffprobeFormat struct {
+	Filename   string `json:"filename"`
+	FormatName string `json:"format_name"`
+	Duration   string `json:"duration"`
+	BitRate    string `json:"bit_rate"`
+	// + unused fields
+}
+
+// GetFileType determines file type and extension to use for media data.
+func (fmt *ffprobeFormat) GetFileType() (gtsmodel.FileType, string) {
+	switch fmt.FormatName {
+	case "mov,mp4,m4a,3gp,3g2,mj2":
+		return gtsmodel.FileTypeVideo, "mp4"
+	case "apng":
+		return gtsmodel.FileTypeImage, "apng"
+	case "png_pipe":
+		return gtsmodel.FileTypeImage, "png"
+	case "image2", "jpeg_pipe":
+		return gtsmodel.FileTypeImage, "jpeg"
+	case "webp_pipe":
+		return gtsmodel.FileTypeImage, "webp"
+	case "gif":
+		return gtsmodel.FileTypeImage, "gif"
+	case "mp3":
+		return gtsmodel.FileTypeAudio, "mp3"
+	case "ogg":
+		return gtsmodel.FileTypeAudio, "ogg"
+	default:
+		return gtsmodel.FileTypeUnknown, fmt.FormatName
+	}
+}
+
+// GetDuration calculates float32 framerate value from format json string.
+func (fmt *ffprobeFormat) GetDuration() float32 {
+	if fmt.Duration != "" {
+		dur, _ := strconv.ParseFloat(fmt.Duration, 32)
+		return float32(dur)
+	}
+	return 0
+}
+
+// GetBitRate calculates uint64 bitrate value from format json string.
+func (fmt *ffprobeFormat) GetBitRate() uint64 {
+	if fmt.BitRate != "" {
+		r, _ := strconv.ParseUint(fmt.BitRate, 10, 64)
+		return r
+	}
+	return 0
+}
+
+type ffprobeError struct {
+	Code   int    `json:"code"`
+	String string `json:"string"`
+}
+
+func (err *ffprobeError) Error() string {
+	return err.String + " (" + strconv.Itoa(err.Code) + ")"
+}