diff options
| author | Samuel Pitoiset <samuel.pitoiset@gmail.com> | 2012-09-10 21:15:09 +0200 |
|---|---|---|
| committer | Martin Storsjö <martin@martin.st> | 2012-09-11 11:53:08 +0300 |
| commit | 55e778bebd6352977eebe406b522e2e9aed7ce35 (patch) | |
| tree | 2b809d8029be59475d81373dd620ea6d5159dfcf /libavformat/rtpdec_jpeg.c | |
| parent | 1648a508fabcbdcefd091fcd7c324ba973437858 (diff) | |
rtpdec_jpeg: Add support for default quantizers
Generate quantization tables when they are not present in the
first chunk.
Signed-off-by: Martin Storsjö <martin@martin.st>
Diffstat (limited to 'libavformat/rtpdec_jpeg.c')
| -rw-r--r-- | libavformat/rtpdec_jpeg.c | 50 |
1 files changed, 47 insertions, 3 deletions
diff --git a/libavformat/rtpdec_jpeg.c b/libavformat/rtpdec_jpeg.c index c77ecbfdef..671763d289 100644 --- a/libavformat/rtpdec_jpeg.c +++ b/libavformat/rtpdec_jpeg.c @@ -33,6 +33,28 @@ struct PayloadContext { int hdr_size; ///< size of the current frame header }; +static const uint8_t default_quantizers[128] = { + /* luma table */ + 16, 11, 12, 14, 12, 10, 16, 14, + 13, 14, 18, 17, 16, 19, 24, 40, + 26, 24, 22, 22, 24, 49, 35, 37, + 29, 40, 58, 51, 61, 60, 57, 51, + 56, 55, 64, 72, 92, 78, 64, 68, + 87, 69, 55, 56, 80, 109, 81, 87, + 95, 98, 103, 104, 103, 62, 77, 113, + 121, 112, 100, 120, 92, 101, 103, 99, + + /* chroma table */ + 17, 18, 18, 24, 21, 24, 47, 26, + 26, 47, 99, 66, 56, 66, 99, 99, + 99, 99, 99, 99, 99, 99, 99, 99, + 99, 99, 99, 99, 99, 99, 99, 99, + 99, 99, 99, 99, 99, 99, 99, 99, + 99, 99, 99, 99, 99, 99, 99, 99, + 99, 99, 99, 99, 99, 99, 99, 99, + 99, 99, 99, 99, 99, 99, 99, 99 +}; + static PayloadContext *jpeg_new_context(void) { return av_mallocz(sizeof(PayloadContext)); @@ -170,6 +192,27 @@ static int jpeg_create_header(uint8_t *buf, int size, uint32_t type, uint32_t w, return put_bits_count(&pbc) / 8; } +static void create_default_qtables(uint8_t *qtables, uint8_t q) +{ + int factor = q; + int i; + + factor = av_clip(q, 1, 99); + + if (q < 50) + q = 5000 / factor; + else + q = 200 - factor * 2; + + for (i = 0; i < 128; i++) { + int val = (default_quantizers[i] * q + 50) / 100; + + /* Limit the quantizers to 1 <= q <= 255. */ + val = av_clip(val, 1, 255); + qtables[i] = val; + } +} + static int jpeg_parse_packet(AVFormatContext *ctx, PayloadContext *jpeg, AVStream *st, AVPacket *pkt, uint32_t *timestamp, const uint8_t *buf, int len, int flags) @@ -238,6 +281,7 @@ static int jpeg_parse_packet(AVFormatContext *ctx, PayloadContext *jpeg, if (off == 0) { /* Start of JPEG data packet. */ + uint8_t new_qtables[128]; uint8_t hdr[1024]; /* Skip the current frame in case of the end packet @@ -249,9 +293,9 @@ static int jpeg_parse_packet(AVFormatContext *ctx, PayloadContext *jpeg, jpeg->timestamp = *timestamp; if (!qtables) { - av_log(ctx, AV_LOG_ERROR, - "Unimplemented default quantization tables.\n"); - return AVERROR_PATCHWELCOME; + create_default_qtables(new_qtables, q); + qtables = new_qtables; + qtable_len = sizeof(new_qtables); } /* Generate a frame and scan headers that can be prepended to the |