On 03/03/15 00:15, Thomas Volkert wrote:
> + has_pic_id = buf[0] & 0x80;
> + has_layer_idc = buf[0] & 0x40;
> + has_ref_idc = buf[0] & 0x20;
> + first_fragment = buf[0] & 0x10;
> + last_fragment = buf[0] & 0x08;
> + has_ss_data = buf[0] & 0x04;
> + has_su_data = buf[0] & 0x02;
> +
if they are flags
flag = !!(buf[0] & mask);
might be nicer.
> + /* sanity check for markers: B should always be equal to the RTP M
> marker */
> + if (last_fragment >> 2 != flags & RTP_FLAG_MARKER) {
> + av_log(ctx, AV_LOG_ERROR, "Invalid combination of B and M marker\n");
> + return AVERROR_INVALIDDATA;
> + }
Might be night to print B and M here.
> +
> + /* pass the extensions field */
> + buf += RTP_VP9_DESC_REQUIRED_SIZE;
> + len -= RTP_VP9_DESC_REQUIRED_SIZE;
> +
> + /*
> + * decode the 1-byte/2-byte picture ID:
> + *
> + * 0 1 2 3 4 5 6 7
> + * +-+-+-+-+-+-+-+-+
> + * I: |M|PICTURE ID | (RECOMMENDED)
> + * +-+-+-+-+-+-+-+-+
> + * M: | EXTENDED PID | (RECOMMENDED)
> + * +-+-+-+-+-+-+-+-+
> + *
> + * M: The most significant bit of the first octet is an extension flag.
> + * PictureID: 8 or 16 bits including the M bit.
> + */
> + if (has_pic_id) {
> + if (len < 1) {
> + av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n");
> + return AVERROR_INVALIDDATA;
> + }
> +
> + /* check for 1-byte or 2-byte picture index */
> + if (buf[0] & 0x80) {
> + if (len < 2) {
> + av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n");
> + return AVERROR_INVALIDDATA;
> + }
> + pic_id = AV_RB16(buf) & 0x7fff;
> + buf += 2;
> + len -= 2;
> + } else {
> + pic_id = buf[0] & 0x7f;
> + buf++;
> + len--;
> + }
> + }
> +
> + /*
> + * decode layer indices
> + *
> + * 0 1 2 3 4 5 6 7
> + * +-+-+-+-+-+-+-+-+
> + * L: | T | S | Q | R | (CONDITIONALLY RECOMMENDED)
> + * +-+-+-+-+-+-+-+-+
> + *
> + * T, S and Q are 2-bit indices for temporal, spatial, and quality
> layers.
> + * If "F" is set in the initial octet, R is 2 bits representing the
> number
> + * of reference fields this frame refers to.
> + */
> + if (has_layer_idc) {
> + if (len < 1) {
> + av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet");
> + return AVERROR_INVALIDDATA;
> + }
> + layer_temporal = buf[0] & 0xC0;
> + layer_spatial = buf[0] & 0x30;
> + layer_quality = buf[0] & 0x0C;
> + if (has_ref_idc) {
> + ref_fields = buf[0] & 0x03;
> + if (ref_fields)
> + non_key_frame = 1;
> + }
> + buf++;
> + len--;
> + }
> +
> + /*
> + * decode the reference fields
> + *
> + * 0 1 2 3 4 5 6 7
> + * +-+-+-+-+-+-+-+-+ -\
> + * F: | PID |X| RS| RQ| (OPTIONAL) .
> + * +-+-+-+-+-+-+-+-+ . - R times
> + * X: | EXTENDED PID | (OPTIONAL) .
> + * +-+-+-+-+-+-+-+-+ -/
> + *
> + * PID: The relative Picture ID referred to by this frame.
> + * RS and RQ: The spatial and quality layer IDs.
> + * X: 1 if this layer index has an extended relative Picture ID.
> + */
> + if (has_ref_idc) {
> + while (ref_fields) {
> + if (len < 1) {
> + av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n");
> + return AVERROR_INVALIDDATA;
> + }
> +
> + has_ref_field_ext_pic_id = buf[0] & 0x10;
> +
> + /* pass ref. field */
> + if (has_ref_field_ext_pic_id) {
> + if (len < 2) {
> + av_log(ctx, AV_LOG_ERROR, "Too short RTP/VP9 packet\n");
> + return AVERROR_INVALIDDATA;
> + }
> +
> + /* ignore ref. data */
> +
> + buf += 2;
> + len -= 2;
> + } else {
> +
> + /* ignore ref. data */
> +
> + buf++;
> + len--;
> + }
> + ref_fields--;
> + }
> + }
> +
> + /*
> + * decode the scalability structure (SS)
> + *
> + * 0 1 2 3 4 5 6 7
> + * +-+-+-+-+-+-+-+-+
> + * V: | PATTERN LENGTH|
> + * +-+-+-+-+-+-+-+-+ -\
> + * | T | S | Q | R | (OPTIONAL) .
> + * +-+-+-+-+-+-+-+-+ -\ .
> + * | PID |X| RS| RQ| (OPTIONAL) . . - PAT. LEN.
> times
> + * +-+-+-+-+-+-+-+-+ . - R times .
> + * X: | EXTENDED PID | (OPTIONAL) . .
> + * +-+-+-+-+-+-+-+-+ -/ -/
> + *
> + * PID: The relative Picture ID referred to by this frame.
> + * RS and RQ: The spatial and quality layer IDs.
> + * X: 1 if this layer index has an extended relative Picture ID.
> + */
> + if (has_ss_data) {
> + avpriv_report_missing_feature(ctx, "VP9 scalability structure
> data\n");
> + return AVERROR_PATCHWELCOME;
> + }
> +
> + /*
> + * decode the scalability update structure (SU)
> + *
> + * spec. is tbd
> + */
> + if (has_su_data) {
> + avpriv_report_missing_feature(ctx, "VP9 scalability update structure
> data\n");
> + return AVERROR_PATCHWELCOME;
> + }
> +
should be AVERROR(ENOSYS), report_missing_feature already prints a
similar message.
lu
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