diff options
Diffstat (limited to 'libavformat/rtpdec_h261.c')
-rw-r--r-- | libavformat/rtpdec_h261.c | 115 |
1 files changed, 57 insertions, 58 deletions
diff --git a/libavformat/rtpdec_h261.c b/libavformat/rtpdec_h261.c index 43244bb..9f34889 100644 --- a/libavformat/rtpdec_h261.c +++ b/libavformat/rtpdec_h261.c @@ -19,11 +19,11 @@ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ +#include "libavcodec/get_bits.h" #include "avformat.h" #include "rtpdec_formats.h" -#include "libavcodec/get_bits.h" -#define RTP_H261_PAYLOAD_HEADER_SIZE 4 +#define RTP_H261_PAYLOAD_HEADER_SIZE 4 struct PayloadContext { AVIOContext *buf; @@ -63,8 +63,6 @@ static av_cold void h261_free_context(PayloadContext *pl_ctx) static av_cold int h261_init(AVFormatContext *ctx, int st_index, PayloadContext *data) { - //av_log(ctx, AV_LOG_DEBUG, "h261_init() for stream %d\n", st_index); - if (st_index < 0) return 0; @@ -73,16 +71,18 @@ static av_cold int h261_init(AVFormatContext *ctx, int st_index, return 0; } -int ff_h261_handle_packet(AVFormatContext *ctx, PayloadContext *data, - AVStream *st, AVPacket *pkt, uint32_t *timestamp, - const uint8_t *buf, int len, uint16_t seq, int flags) +static int h261_handle_packet(AVFormatContext *ctx, PayloadContext *rtp_h261_ctx, + AVStream *st, AVPacket *pkt, uint32_t *timestamp, + const uint8_t *buf, int len, uint16_t seq, + int flags) { int sbit, ebit, gobn, mbap, quant; int res; - /* drop data of previous packets in case of non-continuous (loss) packet stream */ - if (data->buf && data->timestamp != *timestamp) { - h261_free_dyn_buffer(&data->buf); + /* drop data of previous packets in case of non-continuous (lossy) packet stream */ + if (rtp_h261_ctx->buf && rtp_h261_ctx->timestamp != *timestamp) { + h261_free_dyn_buffer(&rtp_h261_ctx->buf); + rtp_h261_ctx->endbyte_bits = 0; } /* sanity check for size of input packet: 1 byte payload at least */ @@ -92,26 +92,25 @@ int ff_h261_handle_packet(AVFormatContext *ctx, PayloadContext *data, } /* - decode the H.261 payload header according to section 4.1 of RFC 4587: - (uses 4 bytes between RTP header and H.261 stream per packet) - - 0 1 2 3 - 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - |SBIT |EBIT |I|V| GOBN | MBAP | QUANT | HMVD | VMVD | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - - Start bit position (SBIT): 3 bits - End bit position (EBIT): 3 bits - INTRA-frame encoded data (I): 1 bit - Motion Vector flag (V): 1 bit - GOB number (GOBN): 4 bits - Macroblock address predictor (MBAP): 5 bits - Quantizer (QUANT): 5 bits - Horizontal motion vector data (HMVD): 5 bits - Vertical motion vector data (VMVD): 5 bits - - */ + * decode the H.261 payload header according to section 4.1 of RFC 4587: + * (uses 4 bytes between RTP header and H.261 stream per packet) + * + * 0 1 2 3 + * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * |SBIT |EBIT |I|V| GOBN | MBAP | QUANT | HMVD | VMVD | + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * + * Start bit position (SBIT): 3 bits + * End bit position (EBIT): 3 bits + * INTRA-frame encoded data (I): 1 bit + * Motion Vector flag (V): 1 bit + * GOB number (GOBN): 4 bits + * Macroblock address predictor (MBAP): 5 bits + * Quantizer (QUANT): 5 bits + * Horizontal motion vector data (HMVD): 5 bits + * Vertical motion vector data (VMVD): 5 bits + */ sbit = (buf[0] >> 5) & 0x07; ebit = (buf[0] >> 2) & 0x07; gobn = (buf[1] >> 4) & 0x0f; @@ -123,14 +122,14 @@ int ff_h261_handle_packet(AVFormatContext *ctx, PayloadContext *data, len -= RTP_H261_PAYLOAD_HEADER_SIZE; /* start frame buffering with new dynamic buffer */ - if (!data->buf) { - /* sanity check: a new frame starts with gobn=0, sbit=0, mbap=0, uqnat=0 */ - if (!gobn && !sbit && !mbap && !quant){ - res = avio_open_dyn_buf(&data->buf); + if (!rtp_h261_ctx->buf) { + /* sanity check: a new frame starts with gobn=0, sbit=0, mbap=0, quant=0 */ + if (!gobn && !sbit && !mbap && !quant) { + res = avio_open_dyn_buf(&rtp_h261_ctx->buf); if (res < 0) return res; /* update the timestamp in the frame packet with the one from the RTP packet */ - data->timestamp = *timestamp; + rtp_h261_ctx->timestamp = *timestamp; } else { /* frame not started yet, need more packets */ return AVERROR(EAGAIN); @@ -138,39 +137,39 @@ int ff_h261_handle_packet(AVFormatContext *ctx, PayloadContext *data, } /* do the "byte merging" at the boundaries of two consecutive frame fragments */ - if (data->endbyte_bits || sbit) { - if (data->endbyte_bits == sbit) { - data->endbyte |= buf[0] & (0xff >> sbit); - data->endbyte_bits = 0; + if (rtp_h261_ctx->endbyte_bits || sbit) { + if (rtp_h261_ctx->endbyte_bits == sbit) { + rtp_h261_ctx->endbyte |= buf[0] & (0xff >> sbit); + rtp_h261_ctx->endbyte_bits = 0; buf++; len--; - avio_w8(data->buf, data->endbyte); + avio_w8(rtp_h261_ctx->buf, rtp_h261_ctx->endbyte); } else { /* ebit/sbit values inconsistent, assuming packet loss */ GetBitContext gb; init_get_bits(&gb, buf, len*8 - ebit); skip_bits(&gb, sbit); - if (data->endbyte_bits) { - data->endbyte |= get_bits(&gb, 8 - data->endbyte_bits); - avio_w8(data->buf, data->endbyte); + if (rtp_h261_ctx->endbyte_bits) { + rtp_h261_ctx->endbyte |= get_bits(&gb, 8 - rtp_h261_ctx->endbyte_bits); + avio_w8(rtp_h261_ctx->buf, rtp_h261_ctx->endbyte); } while (get_bits_left(&gb) >= 8) - avio_w8(data->buf, get_bits(&gb, 8)); - data->endbyte_bits = get_bits_left(&gb); - if (data->endbyte_bits) - data->endbyte = get_bits(&gb, data->endbyte_bits) << - (8 - data->endbyte_bits); + avio_w8(rtp_h261_ctx->buf, get_bits(&gb, 8)); + rtp_h261_ctx->endbyte_bits = get_bits_left(&gb); + if (rtp_h261_ctx->endbyte_bits) + rtp_h261_ctx->endbyte = get_bits(&gb, rtp_h261_ctx->endbyte_bits) << + (8 - rtp_h261_ctx->endbyte_bits); ebit = 0; - len = 0; + len = 0; } } if (ebit) { if (len > 0) - avio_write(data->buf, buf, len - 1); - data->endbyte_bits = 8 - ebit; - data->endbyte = buf[len - 1] & (0xff << ebit); + avio_write(rtp_h261_ctx->buf, buf, len - 1); + rtp_h261_ctx->endbyte_bits = 8 - ebit; + rtp_h261_ctx->endbyte = buf[len - 1] & (0xff << ebit); } else { - avio_write(data->buf, buf, len); + avio_write(rtp_h261_ctx->buf, buf, len); } /* RTP marker bit means: last fragment of current frame was received; @@ -179,12 +178,12 @@ int ff_h261_handle_packet(AVFormatContext *ctx, PayloadContext *data, return AVERROR(EAGAIN); /* write the completed last byte from the "byte merging" */ - if (data->endbyte_bits) - avio_w8(data->buf, data->endbyte); - data->endbyte_bits = 0; + if (rtp_h261_ctx->endbyte_bits) + avio_w8(rtp_h261_ctx->buf, rtp_h261_ctx->endbyte); + rtp_h261_ctx->endbyte_bits = 0; /* close frame buffering and create resulting A/V packet */ - res = ff_rtp_finalize_packet(pkt, &data->buf, st->index); + res = ff_rtp_finalize_packet(pkt, &rtp_h261_ctx->buf, st->index); if (res < 0) return res; @@ -196,8 +195,8 @@ RTPDynamicProtocolHandler ff_h261_dynamic_handler = { .codec_type = AVMEDIA_TYPE_VIDEO, .codec_id = AV_CODEC_ID_H261, .init = h261_init, - .parse_packet = ff_h261_handle_packet, .alloc = h261_new_context, .free = h261_free_context, + .parse_packet = h261_handle_packet, .static_payload_id = 31, }; |