Method to preserve video data obfuscation for video frames
A method and video decoder system using the method are provided for identifying video frames in an encoded or encrypted video stream without performing decoding or decryption. The method includes: receiving a video data stream comprised of a plurality of transport stream (TS) packets; detecting a first video frame in the video data stream, wherein detection of the first video frame includes registering a last checked position at the start of the video data stream, examining bytes in a next TS packet to identify a predetermined pattern indicating a network abstraction layer (NAL) unit, repeating the examining step until two TS packets have been identified that include an NAL unit, wherein the last checked position is updated after each examining step, and identifying a video frame based on a position of the NAL unit identified in the two TS packets; and repeating the detecting step for a plurality of additional video frames in the video data stream.
1. A method for identifying video frames in an encoded or encrypted video stream without performing full decoding or decryption, comprising:
receiving, by a receiver of a computing device, a video data stream, wherein the video data stream is comprised of a plurality of obfuscated transport stream packets;
classifying, by the computing device, a plurality of sequential obfuscated transport stream packets as together comprising both boundaries of only a first identified video frame in the video data stream, without de-obfuscating any portion of the sequential obfuscated transport stream packets, and wherein classification of the first video frame includes
registering, by the computing device, a last checked position at the start of the video data stream,
examining, by the computing device, bytes in a next transport stream packet of the plurality of transport stream packets to identify a predetermined pattern indicating a network abstraction layer (NAL) unit,
repeating, by the computing device, the examining step until two transport stream packets have been identified that each include an NAL unit, wherein the last checked position is updated after each examining step, and
identifying, by the computing device, a video frame based on a position of the NAL units identified in the two transport stream packets; and
repeating, by the computing device, the classification step for a plurality of additional video frames in the video data stream.
2. The method of claim 1 , wherein each transport stream packet includes a data alignment indicator bit indicating that the transport stream packet is unaligned.
3. The method of claim 1 , wherein the bytes in the next transport stream packet are examined without decoding or decrypting the video data stream.
4. The method of claim 1 , wherein classifying the first video frame further includes extracting, by the computing device, the identified video frame.
5. The method of claim 4 , wherein extracting the identified video frame includes transmitting, by a transmitter of the computing device, the identified video frame to a demuxer.
6. The method of claim 4 , wherein extraction of the identified video frame is performed by a plug-in of a browser application program executed by the computing device.
7. A system for identifying video frames in an encoded or encrypted video stream without performing full decoding or decryption, comprising:
a receiver of a computing device configured to receive a video data stream, wherein the video data stream is comprised of a plurality of obfuscated transport stream packets; and
the computing device, wherein the computing device is configured to
classify a plurality of sequential obfuscated transport stream packets as together comprising both boundaries of only a first identified video frame in the video data stream, without de-obfuscating any portion of the sequential obfuscated transport stream packets, and wherein classification of the first video frame includes
registering, by the computing device, a last checked position at the start of the video data stream,
examining, by the computing device, bytes in a next transport stream packet of the plurality of transport stream packets to identify a predetermined pattern indicating a network abstraction layer (NAL) unit,
repeating, by the computing device, the examining step until two transport stream packets have been identified that each include an NAL unit, wherein the last checked position is updated after each examining step, and
identifying, by the computing device, a video frame based on a position of the NAL units identified in the two transport stream packets; and
repeat the classification step for a plurality of additional video frames in the video data stream.
8. The system of claim 7 , wherein each transport stream packet includes a data alignment indicator bit indicating that the transport stream packet is unaligned.
9. The system of claim 7 , wherein the bytes in the next transport stream packet are examined without decoding or decrypting the video data stream.
10. The system of claim 7 , wherein classifying the first video frame further includes extracting, by the computing device, the identified video frame.
11. The system of claim 10 , wherein extracting the identified video frame includes transmitting, by a transmitter of the computing device, the identified video frame to a demuxer.
12. The system of claim 10 , wherein extraction of the identified video frame is performed by a plug-in of a browser application program executed by the computing device.
13. A non-transitory computer readable media having instructions operable to cause one or more processors to perform the operations comprising:
receiving, by a receiver of a computing device, a video data stream, wherein the video data stream is comprised of a plurality of obfuscated transport stream packets;
classifying, by the computing device, a plurality of sequential obfuscated transport stream packets as together comprising both boundaries of only a first identified video frame in the video data stream, without de-obfuscating any portion of the sequential obfuscated transport stream packets, and wherein detection of the first video frame includes
registering, by the computing device, a last checked position at the start of the video data stream,
examining, by the computing device, bytes in a next transport stream packet of the plurality of transport stream packets to identify a predetermined pattern indicating a network abstraction layer (NAL) unit,
repeating, by the computing device, the examining step until two transport stream packets have been identified that each include an NAL unit, wherein the last checked position is updated after each examining step, and
identifying, by the computing device, a video frame based on a position of the NAL units identified in the two transport stream packets; and
repeating, by the computing device, the classification step for a plurality of additional video frames in the video data stream.
14. The non-transitory computer readable media of claim 13 , wherein each transport stream packet includes a data alignment indicator bit indicating that the transport stream packet is unaligned.
15. The non-transitory computer readable media of claim 13 , wherein the bytes in the next transport stream packet are examined without decoding or decrypting the video data stream.
16. The non-transitory computer readable media of claim 13 , wherein classifying the first video frame further includes extracting, by the computing device, the identified video frame.
17. The non-transitory computer readable media of claim 16 , wherein extracting the identified video frame includes transmitting, by a transmitter of the computing device, the identified video frame to a demuxer.