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  1. 1. Data Hiding for Video-in Video by : Mitchell Swanson, Bin Zhu and Ahmed Tewfik Summarized By : Pritam Potnis
  2. 2. What did they Suggest ?? <ul><li>A scheme for hiding high bit-rate supplementary data, such as secondary video, into a digital video stream by directly modifying the pixels in the video frames. </li></ul><ul><ul><li>The technique requires no separate channel or bit interleaving to transmit the extra information. </li></ul></ul><ul><ul><li>The data is invisibly embedded using a perception based projection and quantization algorithm. </li></ul></ul><ul><ul><li>The Data Hiding algorithm supports user defined levels of accessibility and security. </li></ul></ul><ul><ul><li>Algorithm is illustrated by using Real Time Video-in-Video and Speech-in-Video examples. </li></ul></ul><ul><ul><li>Also demonstrates the robustness of data hiding procedure to video degradation and distortions. </li></ul></ul>
  3. 3. Highlights …… <ul><li>Hidden Data remains intact as the host video is compressed, stored and transmitted. </li></ul><ul><li>The Embedded data can be extracted from the video stream automatically or when the user selects a particular temporal/spatial region. </li></ul><ul><li>The embedded data is invisible within the host media </li></ul><ul><li>Hiding data directly into the video data, resolves the problems like synchronization, during playback and additional storage. </li></ul><ul><li>Hiding information in spatial or temporal regions lets the data remain in these regions if they are removed and pasted into another location. </li></ul>
  4. 4. Diagram of Video Data Hiding Algorithm
  5. 5. Diagram of Block Based Projection
  6. 6. Diagram of Embedding Data a) Quantization of projection by masking threshold T, and b) Embedding a ‘0’ by perturbing the quantized value by –T/4
  7. 7. Lets get to the Specifics…… <ul><li>The Approach is based on two steps…. </li></ul><ul><ul><li>Linear Projection </li></ul></ul><ul><ul><li>Quantization and Perturbation </li></ul></ul><ul><li>Each Frame in the video sequence is broken into small blocks and transformed into the DCT Domain. </li></ul><ul><li>Each Block is projected onto a pseudo random (to generate unique author defined signatures) author defined direction. </li></ul><ul><li>The DCT of the pseudo random sequence y is computed [Zij=dct(y)] </li></ul><ul><li>The data is embedded by modifying the projection [p] </li></ul><ul><li>Projection is quantized according the masking based threshold [T=minMij] </li></ul><ul><li>The new projection p’ contains the hidden data. </li></ul><ul><li>The new image is [v’ = v + (p’-p)z </li></ul><ul><li>To Extract Data the receiver projects v’ onto z (z is computed from x by authorized receivers), removes the integer portion of the projection, and evaluates the remainder </li></ul><ul><ul><ul><li>b = 1 If [< v’, z > -{< v’, z >} ] > 0 </li></ul></ul></ul><ul><ul><ul><li>b = 0 otherwise </li></ul></ul></ul><ul><li>The original image block v is not required to extract the embedded data </li></ul><ul><li>One or more bits per block can be inserted by projecting the block onto multiple directions. </li></ul>
  8. 8. Video-in-Video Application <ul><li>Original Broadcast News Video (b) Broadcast News Video with Embedded </li></ul><ul><li>Madonna Video. </li></ul><ul><li>The Madonna Video is the Real -Time Video </li></ul>
  9. 9. What’s Happening in the Video-in-Video Application <ul><li>A 311 frame, 120 x 160 grayscale video of Madonna  video is embedded in an equal length sequence from another movie. </li></ul><ul><li>The Madonna video is embedded for real time playback along with the host video. </li></ul><ul><li>The Madonna video is encoded using MPEG at a bit rate of 294 bytes/frame </li></ul><ul><li>The frames of the Broadcast News Video are of size 240 x 360 </li></ul><ul><li>No degradations of the video sequences are visible </li></ul>“ Unlike PIP, no separate data streams for each video are transmitted for this procedure. Only host video stream is transmitted and the embedded video stream is extracted and displayed in a window within the host video, streamed to a second display device”
  10. 10. Speech-in-Video Application <ul><li>Original Classroom Sequence (b) Classroom Sequence with Hidden Data </li></ul><ul><li>Four Embedded Speech Signals </li></ul>
  11. 11. What’s Happening in the Speech-in-Video Application ??? <ul><li>Speech is also supported by this algorithm. </li></ul><ul><ul><li>Four speech streams are embedded and played back in real time. </li></ul></ul><ul><ul><li>Video: 250 frames (Size: 360 x 240) Original Speech Stream: 8KHz </li></ul></ul><ul><ul><li>A Code Excited Linear Predication (CELP) voice compression algorithm is applied to each speech signal </li></ul></ul><ul><ul><li>Resultant compressed waveforms are coded at 2400 bits per second. </li></ul></ul><ul><li>In this way the Classroom Video can be transmitted with four language options for a multilingual audience. </li></ul>
  12. 12. This Technology …… <ul><li>Can be used to enhance video watching experience by giving viewers the capability to control and personalize what they view. </li></ul><ul><li>Can be used for interactive digital TV or Video-in-Video without a separate channel. </li></ul><ul><li>Can use private author keys, allowing only privileged users to access the data. </li></ul><ul><li>Employs a masking model to guarantee the hidden data is invisible and maximizes the strength of the hidden data </li></ul>
  13. 13. THANK YOU !!!!