diff options
Diffstat (limited to 'vp9/decoder/vp9_decoder.c')
-rw-r--r-- | vp9/decoder/vp9_decoder.c | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/vp9/decoder/vp9_decoder.c b/vp9/decoder/vp9_decoder.c index 1a4155825..e79dcf371 100644 --- a/vp9/decoder/vp9_decoder.c +++ b/vp9/decoder/vp9_decoder.c @@ -314,3 +314,67 @@ int vp9_get_raw_frame(VP9Decoder *pbi, YV12_BUFFER_CONFIG *sd, vp9_clear_system_state(); return ret; } + +vpx_codec_err_t vp9_parse_superframe_index(const uint8_t *data, + size_t data_sz, + uint32_t sizes[8], int *count, + vpx_decrypt_cb decrypt_cb, + void *decrypt_state) { + // A chunk ending with a byte matching 0xc0 is an invalid chunk unless + // it is a super frame index. If the last byte of real video compression + // data is 0xc0 the encoder must add a 0 byte. If we have the marker but + // not the associated matching marker byte at the front of the index we have + // an invalid bitstream and need to return an error. + + uint8_t marker; + + assert(data_sz); + marker = read_marker(decrypt_cb, decrypt_state, data + data_sz - 1); + *count = 0; + + if ((marker & 0xe0) == 0xc0) { + const uint32_t frames = (marker & 0x7) + 1; + const uint32_t mag = ((marker >> 3) & 0x3) + 1; + const size_t index_sz = 2 + mag * frames; + + // This chunk is marked as having a superframe index but doesn't have + // enough data for it, thus it's an invalid superframe index. + if (data_sz < index_sz) + return VPX_CODEC_CORRUPT_FRAME; + + { + const uint8_t marker2 = read_marker(decrypt_cb, decrypt_state, + data + data_sz - index_sz); + + // This chunk is marked as having a superframe index but doesn't have + // the matching marker byte at the front of the index therefore it's an + // invalid chunk. + if (marker != marker2) + return VPX_CODEC_CORRUPT_FRAME; + } + + { + // Found a valid superframe index. + uint32_t i, j; + const uint8_t *x = &data[data_sz - index_sz + 1]; + + // Frames has a maximum of 8 and mag has a maximum of 4. + uint8_t clear_buffer[32]; + assert(sizeof(clear_buffer) >= frames * mag); + if (decrypt_cb) { + decrypt_cb(decrypt_state, x, clear_buffer, frames * mag); + x = clear_buffer; + } + + for (i = 0; i < frames; ++i) { + uint32_t this_sz = 0; + + for (j = 0; j < mag; ++j) + this_sz |= (*x++) << (j * 8); + sizes[i] = this_sz; + } + *count = frames; + } + } + return VPX_CODEC_OK; +} |