CoffeeKnyteandQuick
9281ae61d9
H.264 streams that redefine the same pic_parameter_set_id in-band with different content cannot be safely stream-copied into an avc1/fMP4 HLS segment: the avcC advertises a single parameter set, so VideoToolbox (Safari/Chrome on macOS) decodes with the wrong PPS and desyncs mid-GOP, surfacing as PIPELINE_ERROR_DECODE / kVTVideoDecoderBadDataErr (-12909). At playback start, a bitstream scan (DetectMultiplePPSH264) runs for H.264 files on the probe-ensure path, grouping in-band PPS by id and flagging any id carrying more than one distinct definition. The result is a runtime-only flag (VideoTrack.MultiplePPS, json:"-") memoized per process — never written to the database, no schema change, recomputed on the first play after a restart. The v3 planner and legacy resolver disqualify a copy-unsafe source from the video stream-copy / remux ladder, routing it to a real transcode. Direct play of the original container is left intact: decoders that reparse in-band parameter sets (ExoPlayer, VLC, native) handle the source fine. Part of #135.
80 lines
2.0 KiB
Go
80 lines
2.0 KiB
Go
package scanner
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import "testing"
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// annexB wraps NAL payloads with 4-byte start codes.
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func annexB(nals ...[]byte) []byte {
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var out []byte
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for _, n := range nals {
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out = append(out, 0x00, 0x00, 0x00, 0x01)
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out = append(out, n...)
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}
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return out
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}
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// pps builds a PPS NAL (header 0x68) from the given RBSP payload bytes.
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func pps(rbsp ...byte) []byte {
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return append([]byte{0x68}, rbsp...)
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}
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func TestAnnexBHasConflictingPPS(t *testing.T) {
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tests := []struct {
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name string
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data []byte
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want bool
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}{
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{
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name: "single pps repeated is safe",
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// 0xee -> pic_parameter_set_id=0
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data: annexB(pps(0xee, 0x35, 0x25), pps(0xee, 0x35, 0x25), pps(0xee, 0x35, 0x25)),
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want: false,
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},
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{
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name: "same id redefined with different content is unsafe",
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// both decode to pic_parameter_set_id=0 (leading bit set) but differ.
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data: annexB(pps(0xee, 0x35, 0x25), pps(0xe9, 0x23, 0x52, 0x50)),
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want: true,
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},
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{
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name: "distinct ids each defined once is safe",
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// 0xe8 -> id 0 ; 0x48 -> id 1 ; 0x28 -> id 4
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data: annexB(pps(0xe8), pps(0x48), pps(0x28)),
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want: false,
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},
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{
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name: "empty stream is safe",
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data: nil,
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want: false,
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},
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{
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name: "non-pps nal ignored",
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// 0x65 = IDR slice (type 5), not a PPS.
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data: annexB([]byte{0x65, 0x88, 0x84}, pps(0xee, 0x35)),
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want: false,
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},
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}
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for _, tt := range tests {
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t.Run(tt.name, func(t *testing.T) {
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if got := annexBHasConflictingPPS(tt.data); got != tt.want {
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t.Fatalf("annexBHasConflictingPPS = %v, want %v", got, tt.want)
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}
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})
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}
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}
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func TestPPSParameterSetID(t *testing.T) {
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// pic_parameter_set_id is the first ue(v) of the RBSP.
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cases := map[byte]uint{
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0xe8: 0, // 1.... -> 0
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0x48: 1, // 010.. -> 1
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0x68: 2, // 011.. -> 2
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0x20: 3, // 00100 -> 3
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0x28: 4, // 00101 -> 4
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}
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for first, want := range cases {
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if got, ok := ppsParameterSetID([]byte{first, 0x00}); !ok || got != want {
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t.Errorf("ppsParameterSetID(0x%02x) = %d (ok=%v), want %d", first, got, ok, want)
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}
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}
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}
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