| // Copyright 2018 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef MEDIA_BASE_WAITING_H_ |
| #define MEDIA_BASE_WAITING_H_ |
| |
| #include "base/callback_forward.h" |
| |
| namespace media { |
| |
| // Here "waiting" refers to the state that media pipeline stalls waiting because |
| // of some reason, e.g. no decryption key. It could cause Javascript events like |
| // "waitingforkey" [1], but not necessarily. |
| // Note: this generally does not cause the "waiting" event on HTML5 media |
| // elements [2], which is tightly related to the buffering state change (see |
| // buffering_state.h). |
| // [1] https://www.w3.org/TR/encrypted-media/#dom-evt-waitingforkey |
| // [2] |
| // https://www.w3.org/TR/html5/semantics-embedded-content.html#eventdef-media-waiting |
| |
| enum class WaitingReason { |
| // The playback cannot proceed because some decryption key is not available. |
| // This could happen when the license exchange is delayed or failed. The |
| // playback will resume after the decryption key becomes available. |
| kNoDecryptionKey, |
| |
| // The playback cannot proceed because the decoder has lost its state, e.g. |
| // information about reference frames. Usually this only happens to hardware |
| // decoders. To recover from this state, reset the decoder and start decoding |
| // from a key frame, which can typically be accomplished by a pipeline seek. |
| kDecoderStateLost, |
| |
| // Must be assigned with the last enum value above. |
| kMaxValue = kDecoderStateLost, |
| }; |
| |
| // Callback to notify waiting state and the reason. |
| using WaitingCB = base::RepeatingCallback<void(WaitingReason)>; |
| |
| } // namespace media |
| |
| #endif // MEDIA_BASE_WAITING_H_ |