9b97aedfe4
- HLSSessionConfig.StartSec (sync StreamSession.startSec): el primer ffmpeg arranca ya seekeado en el punto de resume (-ss + -output_ts_offset + -start_number, misma maquinaria que el seek-restart) en vez de encodear desde seg-0 para morir en el seek-restart inmediato del player (doble spawn, resume lento). readyMax se pre-siembra al índice de arranque; el ready-watcher compara ReadyCount() > WriterStartIdx() para no marcar "ready" antes del primer segmento real. startSec >= duración → arranque desde 0 (resume obsoleto de un fichero reemplazado). - Rate control: capped constant-quality donde el encoder lo hace bien — libx264 -crf 23, NVENC -cq 23 -b:v 0 — con el mismo -maxrate de siempre y -bufsize 2x (antes 1x estrangulaba picos). Escenas fáciles emiten muchos menos bits (menos stalls vía funnel/LTE); el peor caso no cambia. QSV/VideoToolbox/VAAPI conservan el triple de bitrate fijo probado (sus knobs de calidad tienen gotchas de vendor). - Limpieza: wrapper buildHLSFFmpegArgs y guard startIdx<0 muertos.
106 lines
3.6 KiB
Go
106 lines
3.6 KiB
Go
package engine
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import (
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"math"
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"strconv"
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)
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// TranscodeRuntime carries the resolved ffmpeg/ffprobe paths + tunables so
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// each session can decide whether to passthrough or pipe through ffmpeg.
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type TranscodeRuntime struct {
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FFmpegPath string
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FFprobePath string
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HWAccel HWAccel
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Preset string
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VideoBitrate string
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AudioBitrate string
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MaxHeight int
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// Disabled forces passthrough for every file even when codecs are not
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// browser-friendly. Useful when the user explicitly turns transcoding
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// off in config.
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Disabled bool
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// TonemapHDR enables HDR→SDR tonemapping of HDR sources during transcode.
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// Set only when the ffmpeg build has zscale (FFmpegSupportsZscale); without
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// it the tonemap filter would error and break playback, so it stays off.
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TonemapHDR bool
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// HasLibplacebo: the ffmpeg build has the libplacebo filter (GPU HDR tonemap).
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// Preferred over the zscale chain for HDR sources — one GPU pass, higher
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// quality, and present where zscale is missing.
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HasLibplacebo bool
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}
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// qualityCap maps a session's Quality label to a (MaxHeight, VideoBitrate)
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// pair. An empty label or "original" returns zero-values, signalling "no
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// override" to the caller.
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type qualityCap struct {
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MaxHeight int
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VideoBitrate string // ffmpeg -b:v string, e.g. "3500k"
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}
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func resolveQualityCap(label string) qualityCap {
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switch label {
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case "2160p":
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return qualityCap{MaxHeight: 2160, VideoBitrate: "25000k"}
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case "1080p":
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return qualityCap{MaxHeight: 1080, VideoBitrate: "6000k"}
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case "720p":
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return qualityCap{MaxHeight: 720, VideoBitrate: "3500k"}
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case "480p":
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return qualityCap{MaxHeight: 480, VideoBitrate: "1500k"}
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default:
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// "original", "auto", "" → defer to config.
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return qualityCap{}
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}
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}
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// doubleBitrate returns an ffmpeg bitrate string with twice the value of the
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// input ("6000k" → "12000k", "1.5M" → "3M", "5M" → "10M"). Used to size
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// `-bufsize` at the standard 2× of `-maxrate` for capped-CRF/CQ rate control.
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// An unparseable string falls back to the input unchanged (1× bufsize — the
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// pre-CRF behaviour, safe just suboptimal). The doubled CPB stays far below
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// every H.264 level's limit for the (level, maxrate) pairs this package emits
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// (worst case: 1080p level 4.1 → 12000k bufsize vs 62500k allowed).
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func doubleBitrate(b string) string {
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if b == "" {
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return b
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}
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num := b
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suffix := ""
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switch b[len(b)-1] {
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case 'k', 'K', 'm', 'M':
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num = b[:len(b)-1]
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suffix = string(b[len(b)-1])
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}
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v, err := strconv.ParseFloat(num, 64)
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if err != nil || v <= 0 {
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return b
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}
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d := v * 2
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if d == math.Trunc(d) {
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return strconv.FormatFloat(d, 'f', 0, 64) + suffix
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}
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return strconv.FormatFloat(d, 'f', -1, 64) + suffix
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}
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// capForHeight returns the bitrate-cap pair appropriate for an effective
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// output height. Used after clamping outputHeight to the source's resolution:
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// asking ffmpeg for "2160p" bitrate (25 Mbps) on a 1080p source overshoots
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// the H.264 level we derived from the EFFECTIVE height (4.0, max 20 Mbps) and
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// makes libx264 refuse with "VBV bitrate > level limit". This helper picks
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// the bitrate that matches the level libx264 will actually accept.
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func capForHeight(height int) qualityCap {
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switch {
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case height <= 0:
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return qualityCap{}
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case height <= 480:
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return qualityCap{MaxHeight: 480, VideoBitrate: "1500k"}
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case height <= 720:
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return qualityCap{MaxHeight: 720, VideoBitrate: "3500k"}
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case height <= 1080:
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return qualityCap{MaxHeight: 1080, VideoBitrate: "6000k"}
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case height <= 1440:
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return qualityCap{MaxHeight: 1440, VideoBitrate: "12000k"}
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default:
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return qualityCap{MaxHeight: 2160, VideoBitrate: "25000k"}
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}
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}
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